This was a tough article to write back in 2016 when we first published it, and it’s a tough one to update, too:
- It was no fun to reverse ourselves from our long-term recommendation of the Rocna anchor.
- The article resulted in more angry personal attacks on me than any other we have ever published, at least since we restricted comments to members.
However, we are dealing with a particularly dangerous dragging modality that could result in lost boats, or even lost lives, so publishing, and republishing, this is worth the aggro. Particularly since being aware of the weakness can go a long way to managing it.
Just wanted you to know I don’t enjoy calling gear that is much loved by many into question.
With that out of the way, on to the meat of it.
Many of you will be aware of the excellent work Steve of S/V Panope has done by rigging up a waterproof video camera in such a way that it allows the viewer to see exactly how an anchor sets, or not, in the real world.
As part of that testing, Steve subjected each anchor to a true resetting torture test by motoring across the position of the set anchor and coming up on the rode at 180 degrees to the original line of set, in order to simulate what happens in a radical wind-shift.
This part of Steve’s testing confirmed that many modern anchors reset amazingly well, even after a radical and sudden pull-angle change.
A Scary Problem
That is, with the exception of the repeated reset failures with the Rocna, which you can see in the video above. To really understand what’s going on here, you need to watch the entire 11-minute video.
Real World, Too
That said, given my general scepticism about anchor testing, I probably would not have written on this if it were not for the reports of sudden and inexplicable dragging of Rocna anchors that we have been receiving over the last few years.
Put the two together, and I’m convinced that there’s a real problem with the Rocna, and that concern extends to the Manson Supreme, since it is so close in design and Steve’s testing shows the same failure.
I have only recently started to use a Vulcan on a small power boat in Bermuda. I expected great things from this anchor in terms of setting ability, but in my limited experience so far, it often takes several attempts to get a good initial set, so I would sincerely doubt that it would do well in a reset test.
James
Hi James,
That’s disturbing and does not bode well. As we both know the hard sand of Bermuda can often be a challenging setting environment, but I have never had even a single setting failure with my SPADE there, albeit in a much larger sizes.
As I type this, we’re on anchor with our 33kg Rocna in a 180 reversing tidal creek with sticky mud. I’ve heard reports from other cruisers about sticky grass/mud in Mexico fouling the fluke/tip after several shifts. That said, most people we see are still convinced an undersized Danforth or CQR is more than adequate…
Hi Lee,
Now that’s a good point.
Based on AC’s recommendation, I started using the Rocna two years ago. All of my sailing experiences so far has been on the coastal waters of Maine. Tidal shifts are pretty normal, especially in a number of river influenced anchorages. I have never had an issue with the Rocna failing to set or reset. That’s a good thing, but to be honest, it has also led me to become overly comfortable and trusting of the set. The two key questions I have from watching the testing relate to scope and anchor weight. The tester makes mention that the 33 lb anchor is probably a tad light for the boat under test. How does this factor mesh with your recommendation to oversize the anchor? I chose the 44 lb Rocna for a 34-foot full keel boat. Second, the anchor was set with a scope of 3.5 to 1, which seems a poor choice given the expected “extreme weather” conditions of the test. I always set with as much scope as possible and then pull back up onto the anchor if I have to reduce the swing radius. I still retain full confidence in the Rocna, but based on your comments, I will be returning to more deliberate measures for monitoring performance.
Hi Jeffrey,
A lot of good observations and thoughts, thank you. The influence anchor weight will have on this is obviously very important and the answer is we simply don’t know. That said, I think the issue here is that the mud unbalances the anchor to the point that the tip no longer comes down properly on the sea bottom surface, the first step to a reliable set.
If that is indeed the case, then I would not expect anchor size to fix the problem. The point being that as the anchor gets bigger so too does the area for the mud to sit on, and therefore it would seem logical that the problem would scale.
The other issue is that we are not just dealing with the above video. We also have several credible reports of this failure in the field, and the Practical Sailor reset tests that also indicated a problem.
Add it all up and I think you cautious observation and monitoring strategy is absolutely the smartest approach.
Since bending our old Bugel type a month ago we bought a Spade on Colin’s recommendation even though he currently uses a Rocna. Anyhow a friend simultaneously took delivery of a Vulcan. Two observations are that mine new 30kg spade looks small compared to his Vulcan even though his is rated for a smaller boat. Secondly the Vulcan does, by all accounts, look higher quality. The welds, colour of material etc.
Point 2 is neither here nor there, let’s face it, so I’ll leave that alone but a lot of people might not like spending that sort of money on a spade when it looks reasonably rough and ready.
Point 1 comes down to manufacturers sizing recommendations. I mean where do we stand on this? Who gets to say what size or weight is correct and is Rocna just way over sizing their recommendations to make its competitors look small or are spades sizings a little on the tiny side?
We’re a 17t displacement so went for the 30kg. Correct size as per their recommendations but it does look small compared to similar Rocnas and especially the Vulcan “equivalent”.
As for performance I can only say that the Spade has been bomb proof up in the Outer Hebrides in what has been regarded the most windy August on record. Happy so far!
Hi Tim
the difference in apparent size is probably easily explained. The Spade is ballasted with lead to make the anchor adopt the correct plane to penetrate the substrate and dig in fast. The Rocna and other roll bar anchors use the roll bar to do the same job, with no ballast. This allows them to move the weight of the ballast into other areas of the anchor, notably the fluke area – so they are bigger.
As far as sizing is concerned, I don’t think there’s much difference in the advice given – A Rocna or Spade of the same weight would do the job. What is different is the anchor sizes – and in my estimation the Rocna 33 (73lbs.) and the Spade S160 (77lbs) are the two to compare, as close to like for like as possible.
Where we all struggle is the old formula trotted out as a general rule of thumb of 1lb of anchor for 1ft LOA. So a 45lb anchor for a 45ft boat. This is/was based around a windspeed of (from memory) 35 knots, which, as we know is nothing in the real world of cruising in remote areas.
So scale up accordingly and sleep soundly!
Best wishes
Colin
Hi Tim,
Added to Colin’s excellent analysis. I address the size issue in this chapter: https://www.morganscloud.com/category/anchoring-mooring/online-book-anchoring/
Dear John
Interesting and scary article about Rocna anchors. I’m using a 33 kg Rocna anchor for our 45′ catamaran and was considering buying a Spade anchor as an extra for our comming circumnavigation, as it is dismantable and therefore easy to store in a locker. But now we might have to change our mind and change to the Spade as our main anchor! I mis a 100% similar test of the Spade anchor, who know if the Spade acts in the same way as the Rocna. Will there come such a test and done at the same location to ensure the test is comparable?
Thank you for many informative articles which we are studying carefully during our preparation for our big adventure next year
Best regards
Kjeld
Kjeld,
Later in the video Steve (who made it) points out that he did exsactly the same test on the SPADE in the same place and it passed every time, together with three other anchors. You will also find a video of those tests on Steve’s YouTube site: https://www.youtube.com/watch?v=l59f-OjWoq0
If it were me, I would buy a spade as best bower and keep the Rocna as a spare. You will find a complete step by step set of recommendations to build a good offshore voyaging anchor inventory in this online book (chapters 2-4): https://www.morganscloud.com/category/anchoring-mooring/online-book-anchoring/
On our previous boat, a Baba 30. We had anchored many seasons on a 35lb CQR that was original to the boat. After hearing all the talk of the new anchors we purchased a 33lb Vulcan (roll bar anchors will not fit on our bow). We only used it last summer before selling the boat this May, but my experience was very similar to the video. It would set beautifully in nearly all conditions; however some of our anchoring was in the Hood Canal, in an area with about a 2.5 knot tidal current. When we were anchored there; 33% of the time the anchor would drag on the tide change. We got in the habit of always being on the boat during the flop and if we felt like we hadn’t gotten a good reset we’d power set the anchor often dragging for a bit. I began to think that it’s actually a balance problem, once anything (mostly sand up here) weights the back side of the fluke down where all the area is, the tip is no longer heavy enough to bite. Unfortunately, our new boat, a N447, has a brand new 73 lb Rocna on the bow … I guess I’ll need to start budgeting for a Spade.
Hi Dartanyon,
Thanks very much for the very useful information. I think you are exactly right in your theory on the cause of the problem. For me that rather settles it. Without fabricated construction and lead in the tip, like the SPADE, it’s simply not possible to get a high enough percentage of the anchor’s weight onto the tip to insure re-setting when there is mud on the fluke.
The late Alain Poiraud, designer of the SPADE said as much 25 years ago, and it seems that he was, and still is, right.
While I think this sort of test is informative to a point, I always marvel at the idea that 3.5:1 is anything better than a “lunch-hook” ratio. It’s not something I would seriously attempt. Even in calm-10 knot air with a known ground, I lay out 5:1 (often on a oversized Fortress for “lunch” purposes or if we wish to swim from the boat).
What *is* helpful is seeing the setting behaviour. I saw Steve’s 4:1 SPADE test (#27: https://www.youtube.com/watch?v=KvVITS3nHHQ) and that shows very convincingly the weighted tip advantage. Even if I would never close my eyes at less than 6:1 even if the forecast was benign. One of the most distressing aspects of “new model anchor” marketing is the promise of “you have the holding power of 7:1 at a scope of 5:1!” Well, that implies the same old scope of 7:1 gives you close to the hold of 10:1…why wouldn’t you just keep the old conservative habit, which allows shock loading and a proper catenary?
Thanks, John, for wading (again) into this. We’re getting a SPADE. It’s less that 1% the cost to replace our boat, not counting every improvement and thousands of hours of labour. Why does price even enter into that equation?
Hi Marc,
I agree with you on the benefits of scope, although I have never found that any more than 5:1 was beneficial. In fact I think it likely that excessive scope may actually be detrimental since the boat can get going faster and further when being thrown around by multi-directional gusting. (See Christopher’s comment.)
Also, there is no good engineering to support the idea that excessive scope provides more catenary, or that catenary provides any shock damping. This is an old myth and often repeated one, but it’s simply not true. In fact engineer Eric Klem has shared in the past that there is actually more shock amelioration due to stretch in the chain than catenary!
Bottom line, we should always use a snubber.
Very good point that even an expensive SPADE is cheap when compared to the boat it protects.
Re: snubber/bridle: Sorry, I thought that was implied, John. Only in the “benign lunch hook” scenario (which implies a rope rode with a chain leader, little wind or tide and a known, decent ground) do I anchor without a waterline snubber or a bridle.
As for catenary, I think it’s been shown that you can get away with less scope in deeper waters without penalty, but the anchor tests shown were done in shallow (9-15 feet) of water, which is where I would not consider 3.5: 1 or 4:1 to be realistic for overnight.
As for price, the SPADE “S” Steel S140 (30 kilos/66 pounds) is $1,175.00 (U.S.) on the U.S. distributor’s site, whereas the most comparable Rocna (73 lbs.) is $859.00 (U.S.) at West Marine. So, less than one third of a boat buck. Everything’s relative.
Hi John,
Is there a citation to Eric Klem’s observation that there is more shock absorption in chain stretch than in catenary?
Thanks, Dick
Hi Dick,
Not that I know of, but if he says it’s true, I believe him. Off hand I can’t remember where the comment is, but I pretty sure that he said he had calculated that.
Hi Dick,
Sorry for jumping in here so late, we just got back from a few weeks off the grid on the boat.
Let me start by clarifying the statement slightly. Going from a “reasonably high load” all the way up to the yield strength of the chain, the difference in the distance of the endpoints of the chain will vary more due to the chain deforming (elastically meaning it is not permanent) than due to the catenary. For reasonable load, I am talking something on the order of 1/10th the tensile strength depending on the specific situation. If you start at a really low load, then catenary obviously is a major factor until you get into higher loads.
The way I came to this conclusion was by calculating it out one night when someone pointed out to me that I always ignored link deformation. I don’t have the calculation in front of me but I believe I was using 200′ of 3/8″ HT chain with an ideal catenary curve (2 attachment points horizontal to each other with no ground in between) and a starting load of 1000 lbs. I then recalculated at a few other loads like 2000,3000, 5000 lbs and found that the difference from 1000 lbs was greater for link deformation than catenary. For anyone interested in learning more about catenary, I highly recommend googling something like “catenary calculator” and plugging in numbers. The most interesting thing to look at is the distance between the cable/chain length and the distance between the attachment points, they are almost the same for any reasonably high load meaning that taking out additional catenary will dissipate very little energy.
I hope this helps.
Eric
Hi Eric,
Thanks for a very interesting comment. I think I need to do more research along the lines you suggest, improve my own understanding (I hope) and then write a chapter about this that we can reference going forward.
Hi Eric,
Yes, it does help. Every little bit helps me to wrap my head around the various elements that contribute to keeping Alchemy struck to the bottom and which are likely to make the most difference when things heat up a bit.
Thanks, Dick
I differ on one several facts, and this is almost certainly because I think anchoring in 5 feet of water is a normal thing (catamaran, mud bottom, little tide range) and I use outboards for power (weak in reverse). I’m pretty sure you would have a foot of boot top showing in some of my favorite places. Though I’ve not voyaged, I’ve done enough instrumented testing to pretty sure of a few things. Engineering.
In that sort of thin water, a 3:1 scope is only 24′ of chain (including an allowance for freeboard). First, with a bridle or any decent snubber, that is practically no chain. Setting is nearly impossible, because even on all chain (remember that you have almost no chain in the system–catamarans rig the bridle before setting, or we would be backing down against the windlass), it doesn’t take but 20 pounds or so to lift the chain off the bottom. So the “no engineering basis” comment requires a caveat stating “for depths over 15 feet.” Otherwise you need more rode to set.
Second, although after setting I agree that scope has less impact than commonly thought (the chain is at a different angle underground), that is not true during the initial set, and with over-size anchors, most sail boats cannot set the anchors deeply with reverse. I know I can’t. With any large anchor in good sand, the shank will still be on the surface and the scope is what the anchor will feel. We rely on the storm to provide the real setting force, and that means we will need longer scope for a while, during this extended setting. I think that math is defensible.
Finally, I’ve never seen my cat sail at anchor at all (long bridle). I also have more limited mass. Thus surging is a non-issue for me. However, watching some boats zig through what must be their tacking angle, I agree that is a MAJOR issue. And it would drive me crazy being on board.
In deeper water, and after the anchor is set, we are on the same page. I broke a load cell testing with no snubber (just for background info) when a 2-foot wake came through in only 10 knots. Bam. I was sitting right next to it and was jolted. Felt like we hit something.
Drew, interesting and (to me, even with a heavy displacement monohull) relevant observations, especially on the suggestion that there’s a lower limit of chain rode out that could be considered “enough”. Your difficulties with power sets in reverse would indeed make for different techniques by which you could compensate for that tricky period before your anchor “self-buries”. As for surging, veering and hunting at anchor, there are means to lessen this, such as riding sails, that just aren’t as common as one might think.
I’ve always wondered how much a dinghy lashed to the foredeck impacts sailing at anchor. I have a large hardtop and davits (plenty of windage aft) and a bridle. On the other hand, it seems to me that some of the most nervous boats are those with a dinghy up front. Sort of a reverse riding sail.
The corollary is what advise should be given for storms. Deflate the dingy? Take it ashore? I’ve heard of dinghies flipping in high winds when left floating; I always wonder how long the painter was and if the boat was sailing a lot. Otherwise, how did the dinghy get out into the wind stream? Would it have been OK on a very short, properly centered tether? I suppose this depends on how much the boat surges, causing it to get sideways once in a while.
Still, the foredeck seems wrong, even for a strong squall.
Hi Drew,
I have never noticed that having the dinghy on the foredeck makes a lot of difference, either way. But them we have a big boat that does not sail at the anchor badly and a small dinghy.
Here is our standard high wind preparation check list: https://www.morganscloud.com/2009/09/01/gale-and-storm-preparation/
Note that we deflate the dinghy and put it below at the higher end of the wind range. One the the many reasons we won’t have a RIB.
On the other hand, I think your concern would be absolutely valid in the case of a large dinghy on a small boat. When I see 15′ RIBs upturned on the fordeck of 40′ boats I absolutely cringe for a whole bunch of reasons, and you concern is just one more.
Hi Drew,
I agree 100%. What I was referring to was the effect, or rather lack thereof, of excessive scope on ultimate holding (once set) and shock absorption.
I was not referring to setting, where the dynamics are different and with most anchors (except Danforth types) more scope pretty much equals an easier set, at least as long as the skipper is gentle on the throttle when backing down to get the initial set, particularly in difficult bottom types such as very soft mud.
Hi Marc,
I would encourage you not to get too hung up on one specific scope number. If you are unable to sleep at anything less than 6:1, you will miss an awful lot of good anchorages and take up more room than is courteous in many more. I just got back from anchoring in a place where tides are greater than 20′ and most of the anchorages are around 20′ MWL so we would have >45′ between the bottom and bow roller often and we often could only put out 150′ or we would hit something. In our most common cruising grounds, I would estimate that I would have to bypass a full third of the harbors we go into if I had a 6:1 rule and I don’t think of myself as particularly adventurous. In the Pacific Northwest, I would guess that the number would be above half, some people there anchor at insanely short scope although it can also be ridiculously deep, there are many anchorages there that I refuse to go in.
I always refer to my scope as what I find at high tide. If there is going to be greater than 30′ of water, I shoot for 3.5:1 or greater with a normal forecast because I have tried to torture test our anchor at shorter scopes than that and been unable to generate a failure until much shorter scope. As the water gets shallower, I slowly increase the scope until I hit the point where I never let out less than 50′ and rarely less than 70′. By using at least 50′ at all times, I don’t have to worry about the anchor struggling to set because of the chain pulling up too much on it. If you are sailing in clear waters, I like to make sure that there are always at least a few links of chain sitting on the bottom even in the big gusts.
Like John, I shoot for 5:1 in poor weather as long as the water is relatively deep. We carry 225′ of chain because it equates to 5:1 in 40′ of water for us. I have not experimented on our current boat but on other boats, I have found that excessive scope leads to excess yawing.
Eric
Thanks for your comments, Eric. I do take tidal factors into account and hope to anchor in both Nova Scotia and Brittany (again, but in our own boat) in the reasonably close future. All my comments regarding scope can be taken to be idealized rather than a hard and fast (pun unintended) viewpoint. Of course, crowding, state of the ground and weather forecasts, currents, tidal range/time of the month, etc. all play a role. Let’s face it, a lot of people who grasp little or none of these things never drag, just as people who carry drogues never see more than 40 knots. Preparedness goes in two directions in that respect.
Spade 160 anchor on a 47′ aluminium boat, 3 years live aboard experience to a few remote places. We dragged exactly twice:
1) Anegada in the BVI, user error (idiocy comes to mind actually) combining anchoring in 1.2 meter depth, tight anchorage, short scope (3:1), and forgetting the height off the water of the bow (1.5m)… 36 hours later + 20 cm of tide and she was off to visit the other boats in the anchorage. Can’t blame that on the manufacturer or design.
2) We were in Elephant Cove on South Georgia, anchored in a 5-6m depth with 40+ m rode in significant williwaws for 8+ hours with 40 knots from one side and then 45 knots from the other a minute later. Tacked briskly back and forth on the rode all day and finally we noticed (needed radar over several minutes to confirm) we were very slowly easing back – figured we had literally plowed and furrowed the ground around the anchor. Ground was pink mud (Krill in the local Fur and Elephant seal diet) and pretty slick stuff. Always wondered if we might have been better off on less scope that day. A small sea anchor on the rode would have helped a lot. Never doubted, nor dragged once set, the Spade at other times when it really blew hard.
Hi Christopher,
Your second experience highlights one of the huge advantages of the SPADE: even if it does drag due to a poor seabed it does so very slowly.
In over 20 years of SPADE use, we have never dragged once set, but we have noticed the same behaviour on the few occasions that the anchor has not fully set under the assault of our large engine at 3/4 power: a very slow and steady drag back with no jumping or skipping.
For those that don’t know Christopher, it’s worth knowing that his endorsement is based on an incredible voyage to some really tough places: https://www.morganscloud.com/2015/07/02/boreal-47-an-owners-experience/
Also, I would expect, the continued hard pulls side to side have to allow at least a few inches of movement before reset: like wiggling a spade shovel in the earth to get it a bit lower when digging. These have to add up over time, but likely not in any problematic way.
Dick Stevenson, s/v Alchemy
Hi John,
Once again thank you for your very useful site.
My experience with anchors is limited to CQR.
I had a 45lb on the 45ft 20t yacht and dragged on several occasions .
After anchoring badly in 50 knts and a big swell I ripped the chain through the timber bowsprit after demolishing the roller set up/
In the repair I changed to a 60lb CQR and upped the chain from 10mm to 13mm and never dragged again.
Now on the 80 ft Lloyds require a 100 kg CQR and I have upped that to 130kg .
I also calculated the angle of a 5: 1 scope from the bow roller to the ancor set in 10m.
By leading the snubber through a block attached at the waterline I found that a scope of 3:1 gave me the same angle. I believe this angle is the critical factor rather than the scope.
Lloyds required a 16mm chain and this has a break of 12t.
I consider that inadequate on a 58t yacht taking into account snatch loads, as in a large swell, and went to a 16mm stud link chain which did not increase the weight a great deal but increased the break to 19t.
As my spare anchor, I will follow your advice and get a 165lb (72 kg ) Spade and an alloy Spade for my stern anchor. These will also be much easier to sow and deploy. The large CQR was not a lot of fun to manouver in and out of the sail locker even with 2 cranes and 2 people. Would have been fun with a jockey pole and electric winch by myself.
I also worried about a large size and weight on the bow in a seaway and built a box that turns over the same axle as the roller which then moves the weight forward allowing the anchor to self launch while holding the anchor tightly in the stowed position both vertically and from side to side. This box also encloses the chain so it cannot jump the roller cheeks.
Finally a word of warning re hi tensile and load rated shackles.
These are not to be used underwater as they will suffer from hydrogen embrittlement leading to sudden failure.
Kind Regards,
Bill Koppe.
Hi Bill,
If it were me, I would simply get rid of the CQR and replace it with a SPADE SQ240 at 165 pounds, or even a SQ380. You will have much, much, better holding and setting than with the CQR. I can say this with some certainty since I too anchored for years with a CQR before switching to a SPADE.
See more on our recommendations for anchors, chain, and shackles in our anchoring online book: https://www.morganscloud.com/category/anchoring-mooring/online-book-anchoring/
It’s 0338 hrs in Newport harbor RI. A couple hours ago a squall came through with 180 degree wind shift. Estimate 0 kts to around 25-30 kts. Our 55lb Rocna pulled and we drug into a cat anchored too close. I estimate a 100 meter drag before we reset. Had 100′ of chain out. We’re a 18000 lb sailboat. Muck bottom. Several other boats drug. We’ll pull at first light and see what’s up. Time for a quick nap.
Hi Clarence,
Yikes, talk about realtime real world testing. I’m really sorry to hear that. Being awoken by dragging is always a horrible event. Thanks for taking the time to share at the end of it all. I will be very interested to hear what you find on the anchor.
Hi John,
We have corresponded before on anchors, and you did indeed recommend me to use a Spade over a Rocna. I am due to make a final decision on this shortly (as the boat is currently under construction). This has now got me over the line for a spade ! Now I need to go and figure out sizing. I noticed on the spade web site that their anchors are offered in three different types of material…can you give me a steer. My yacht will be 47 feet and built from aluminium.
Many thanks
Tim
Hi Tim,
We have complete sizing recommendations in our Online Book. Definitely worth reading right through chapters before you buy any anchors or related gear: https://www.morganscloud.com/category/anchoring-mooring/online-book-anchoring/
this is a film from carib, showing the Spade not doing what it is made for ? https://www.youtube.com/watch?v=-v6ws82gMF8&feature=youtu.be
i think the setting of the anchor is more important, and Rockne and spade are good anchors.
My comment is about the methodology of this powered reversal test.
I assume that the two lines which appear attached to the roll bar are for the camera. When the reversal takes place I see the two lines billowing. Because of the apparent attachment to the roll bar there is a leverage on the anchor which is reducing the tips downward force. How much?
When the speed is slowed the force on the camera lines is reduced and the tip has more downward force.
But, this does not account for failures to reset where there are no lines attached to, presumably, the roll bar.
We upgraded (?) from 45 lbs Delta to 45 lbs Vulcan last year and so far no problems. Our boat is 35 ft Cape Vicker made in South Africa to B. Roberts design. We are currently in Mexico …relatively easy cruising grounds. Either sand or rocks….I will keep you posted.
Marek
Hi Marek,
Thanks very much, we will look forward to your ongoing reports.
Thanks again for a helpful article. Because of extreme paranoia I’m ready to switch out my Rocna (which has never dragged, but then I mostly cruise on the Chesapeake and occasional forays down the ICW to Miami). My simple minded question is what do I do with the Rocna. There doesn’t seem to be much of a market for used anchors unless I really mark it down. If I want to keep it as a spare, where do I store it on my Island Packet 380?
Hi Reuben,
I feel your pain. We went through the same thing when we junked our CQR, which is now a lawn ornament in Norway. I’m sticking my neck out here, but given your cruising grounds I think you could get away with keeping the Rocna as long as you remain aware of the problem and check the set after any 180 degree wind or current shift.
These videos are hugely helpful but it is fascinating to note that there really hasn’t been a definitive comparative scientific study of anchors done by a neutral party to really answer the questions of holding power, scope requirements and resetting capabilities (in a variety of substrates) for the major anchors on the market.
This thread on cruisers forum is very informative: http://www.cruisersforum.com/forums/f118/photos-of-anchors-setting-126073.html
But, it really only represents a series of anecdotal reports.
The definitive study has yet to be done.
-evan
Hi Evan,
I agree, no definitive study exists. However, I take it a step further, I don’t think a definitive study is even possible, or certainly not at the level of funding available to the sailing community. Given that, I believe that actually anecdotal reports from credible and experienced sources are the best answer. More here:https://www.morganscloud.com/2015/10/09/anchor-tests-the-good-the-bad-and-the-downright-silly/
I also think that the S/V Panope Videos in conjunction with the reports we have of Rocnas failing are pretty convincing.
Hi John,
A little more clear headed. A little more about our dragging event last evening. Island Packet 35 anchored in 15ish water. Rocna 25 with 100 ft of chain out. We hard set the anchor every time. We’ve been here a week and have ridden out several squalls without any issue. Last night, a squall line passed close. The outflow from the line blew approx 180 degrees from our resting heading. In hind site, what woke us up was a windscoop on a hatch inverted due to high winds making a loud racket. I then felt the boat surge forward. Not sure if we initially swung 180 or simply road over our anchor on our original resting heading. In any event, we dragged around 25 meters not my original estimate. A cat was anchored a short distance away. He may have also dragged a bit. We swung beam to beam without any noticible damage. The anchor did reset on it’s own and has held fine. The cat moved to a more open spot. From prior experience here, it is think mud. We usually need to use a boat hook to remove the mud, a pressure hose is not enough. We’re full time cruisers and this is the first time we have had an issue with our Rocna. While the initial gust was high and short lived, we’ve ridden out storms with much higher winds in similar bottoms. We carry a large Fortress as a spare. We see far too many boats drag. Biggest issue we’ve experienced in these waters is the mix of full keel, fin keel, motor boats and cats anchored too close, not understanding they all swing a bit different. We always ask our neighbors how much rode they have out. Too many don’t know or think if they have all chain, they can break the ratio rule significantly. Too many boats are not using snubbers on their short scope.
Hi Clarence,
Really glad to hear that there was no damage done. Thanks very much for the update, all very useful stuff.
I worry about a couple of factors in this testing.
1) he is testing a 33lb Rocna anchor rather than 40-50 class of the others. As he bounces back on the anchor the boat weight will have a greater effect on the lighter anchor putting the Rocna at a disadvantage. (since the boat force is similar but the Rocna is the smallest anchor)
2) he is setting the anchors at 3.5:1 and even 2.5:1 scopes and backing up at 3 knots
The test is worthwhile but does seem to be mainly testing one dramatic scenario. Resetting at a high speed with short scope. All round performance of any anchor is important, not just one scenario.
Aboard Distant Shores II a 49 foot Southerly we have a Rocna 33 (73lb) as our main anchor and it has been quite reliable. In our 7 years and 30,000 miles the Rocna has been excellent. From The Baltic to Northern UK and Norway, The Bahamas Caribbean and in between it has slipped only twice. (once in extremely soupy mud in St Martin Lagoon, the other time in grass in Denmark). Just recently our Rocna held both our 49 foot monohull PLUS also a 51 foot monohull that dragged on top of us in sustained 30-35 knots gusts. I would want to see more tests before giving up on this excellent anchor.
Hi Paul,
I agree that the testing in the video is far from perfect and if that was all we had to go on I would never have written this post. But given that we have more and more reports from the field of this failure and that we were recommending the Rocna as best bower, something had to be said.
Incidentally, some testing done by a deeply experienced AAC reader we trust yielded the same failure to reset on a much larger anchor and with more scope. His theory, which I support, is that weight of the adhered mud on the fluke near and under the roll bar unbalances the anchor to the point that it skates along the bottom on the flat underside of the fluke. As soon as the mud washes off balance is restored and it resets. A really close look at the video seems to support this view. Assuming this is the true modality, then it seems likely that weight and scope will make little difference.
As you say, a best bower must work in a the widest possible selection of scenarios. In my view, the anchor that does best in this regard is the SPADE. That does not make the Rocna a bad anchor but it does mean that Rocna users need to be aware of the problem.
Here is a link to our recent anchoring video showing the 33kg Rocna 50 feet down with short scope. We were testing shock loads banging back on the anchor.
https://youtu.be/w4qO_dIegaM
I would like to be able to test the Spade sometime. They look like a good anchor. You have obviously had good luck with yours.
Hi Paul,
Yes, we have had very good service from the SPADE from Grenada to Greenland over some two decades. Bottom line, it has never in all that time dragged once set,
Having said that, as I have written before, I don’t think the SPADE is quite as good as the Rocna on very short scope, but I could be wrong about that.
As to testing a SPADE, you might try writing to Alex at the SPADE NA distributor to see if you can set that up: https://www.spadeanchorusa.com/
Hi,
It should be noted that the test was done at 3.5:1 scope. On the Rocna site 3:1 is stated to be the minimum, with 5:1 considered “appropriate”. Perhaps you would get different results if the designers recommendations were followed? That said, if another type of anchor will consistently reset at 3.5:1 is would be preferable. Maybe Rocna needs to teflon coat their anchors so mud won’t stick?
Hi Steve A,
My guess is that more scope will not make much, if any difference. See my answer to Paul Shard for my thinking on that.
More questions
If the mud washes off and this allows the anchor to reset, what conditions promote washing off the mud: time, speed, angle to bottom, teflon ? And if reset occurs when the flukes near the roll bar are clean, then how do we understand the resetting at much slower speeds? Did the mud come off? When did the mud come off? Was the speed over the bottom a factor in resetting? Was time dragging a factor in resetting?
Revelations: 47 feet mono, ~50,000 pounds, 40Kg/88Lb Rocna
Hi Doug,
If the Rocna is like the Spade, and I assume it is with regard to the loading up of bottom material, then it can be very hard to remove, often impossible without raising the anchor and manually cleaning it. We have a good wash down pump and still often need a boat hook to loosen the muck (possibly the only down side of these anchors). I suspect that it is quite unlikely either anchor would clean self-clean itself on the bottom.
Dick Stevenson, s/v Alchemy
Hi Doug,
All good questions, however, as I have written above, none of this is, unfortunately, that well defined.
Having said that, I think that you are right to bring up the reseting at slower speeds and I do think that this failure is dependant on the speed of the boat, when she comes up against the anchor after the wind or current shift, being quite fast. And my guess is that this is the reason that the failure is quite rare.
Hi
Started this year with upgrading our 20 kg Delta to a 25 kg Vulcan. We are now for 16 months full time cruisers.
The performance so far of the Vulcan has been excellent. We had however a situation where our fellow sailors quick action saved the day. Not onboard, sudden strong gust and the Vulcan failed to reset after dragging. It was well set and 4:1 scoop. We can’t however absorb this as the Vulcans fault since it happens in notorious Nidri bay in Greece, where the ground is so plowed up making it unreliable. Have however made us more on the watch.
Can so far recommend the Vulcan since it in many other situations have been proving itself when others have had problems.
Hi Dennis,
Thanks very much for the report. One question: when the Vulcan dragged had you set it hard with the engine when you anchored and did you have any trouble getting it to set when initially dropped?
Anchor was set with 2/3 throttle and set directly.
However when reanchoring we had to have several tryouts in different spots before it was holding. Found out after that the ground was “broken” due to frequent anchoring.
Haven’t had that problem before or after and others did also have problems. So for now I consider it a exception. Will revert with updates if any.
Need however to say that the Vulcan have “saved” us from problems many times when others had problems.
And as someone wrote, there is no perfect all around anchor which is why your spare should be of another “kind”
This is my takeaway, too. We are thinking a SPADE (upped two sizes) and a big Fortress as the most “opposite mode of action” anchors we could have at the bow, but I will likely keep the real Bruce I have for the few types of bottom in which it seems to have a good track record. We may be approaching “peak anchor” in terms of all-arounder designs, and I still don’t buy a test that doesn’t include the full suite of variables. I don’t find them uninformative, just not comprehensive. Heck, Panope’s test of his child yanking a Bruce around a beach on a rope rode did demonstrate how it works.
Hi Marc,
If it were me, I would ditch the Bruce and replace it with a spare SPADE or Rocna. I’m pretty sure there is no bottom type or anchoring situation in which a Bruce will be better than pretty much any of the new design anchors. Bottom line, the Bruce was once a good alternative, just as the CQR was, but it is now obsolete. Also, the Bruce’s drag modality is scary: it skips along the bottom allowing the boat to drag very quickly.
Hi Marc
sorry – I missed your question.
We were anchored further out than many of the boats on both occasions, as if it’s busy and we can’t find plenty of swinging room we’ll move into deeper water to find it. We (almost) never anchor with less than 5:1 scope to an all chain (10mm) rode. We have 80m of chain spliced to 30m of 20mm octoplait in our main rode.
If we think the wind will get up we’ll veer more cable to say 7:1 and on the first occasion (from memory) that’s certainly what we had out. The second occasion came out of nowhere and we may have had 5:1 out. Otherwise, it’s a case of veering more cable in a hurry and we go to about the same scope. We have at least one snubber attached to a specially sited cleat in our bow locker that passes out through the starboard roller. We carry three of these, all with chain hooks.
These are all 18mm 3 strand nylon of 20m length.
We have anchored using the same basic set-up thousands of times with no problem.
But the conditions when we dragged were really extreme – sudden 180 degree wind shifts as the squalls rolled down off the hills. That was what caught us out on both occasions. The first time could have been really bad – we actually clipped the anchor cable of the boat we were on top of with our rudder while we were getting the engine going and preparing to haul the cable – a very close run thing. We motored upwind in blinding rain and anchored again – the Rocna bit first time, no problem. The second time we had loads of room and it was simply the case that we dragged for some distance, then held.
So we now always get up at a big shift and dig in again for the new direction. And very occasionally we’ve had to get the anchor up and clear the mud and set it again. We know the issue, so we deal with it practically.
And we’re ultra careful if we expect a front going through to move to the best spot to be ready for the shift. In fact we’ve just done so where we’re at anchor here in Nova Scotia. And we’ll be watching out when the shift comes through overnight. This isn’t difficult stuff – just the kind of sensible precaution that’s required.
Compared with the shenanigans I used to face before these ‘new generation’ anchors were available, it’s absolutely nothing at all….
Best wishes
Colin
Thanks for the informative reply, Colin. Anchors aren’t miracle machines, and you clearly have a Plan B for when the miracle doesn’t stick. Unfortunately, some of the most beautiful anchorages are often nestled between the sort of hills the wind likes to sledge down. Twenty metre snubbers? That’s impressive!
Hi Dennis,
Sorry to keep bugging you with questions, but I have one more and it’s important.
When you went to re-anchor and had trouble, had you cleaned the anchor off of mud back to bare metal before the first attempt and between attempts?
Hi Marc & Dennis,
As to your comments as to the “spare” anchor being of a different kind to cover different bottoms, I am not sure I agree. A Fortress on the bow certainly can be used as a spare anchor, but I believe that most think of it not as a bower or even as a spare for the bower but rather as a kedge, for which it is ideal. Or as a spare anchor to dinghy out if needed, again an ideal anchor. But I would never consider it as a spare for the bower.
For years I had a spare anchor of a different type, a Luke, which I considered a storm anchor and (under duress) a spare for the bower. I sold the Luke a few years back and now have 2 Spades: one taken apart in the bilge and one as a bower. I no longer think of different design anchors being a wise strategy as bottoms differ. The Spade has worked better than any other anchor in a wide variety of bottoms I have used it on than any other anchor and if I lose an anchor I have a spare I trust. The Fortress is for easy transport in trouble shooting situations and (I believe) should not be considered a spare for a bower.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
I agree, in fact we have a whole article on just that: https://www.morganscloud.com/2015/06/10/third-anchors-storm-anchors-and-spare-anchores/
Having said that, were I starting from scratch, I might consider a Rocna as a spare to a SPADE because I do think that the Rocna has some advantages over the SPADE including a bit better short scope performance and a larger fluke area for a given weight, which should be useful in very soft seabeds.
Of course if I then lost the SPADE I would be faced with managing the re-set risk of the Rocna until I could buy another SPADE, but I think that risk is perfectly manageable with a bit of vigilance, at least on a temporary basis.
Dick/John: Sorry if I misled with my comment: I don’t consider the Fortress at the bow as a “spare” so much as a lunch hook due to its ease of deployment and good holding with a mixed rode, a easier proposition for a stop ‘n’ go in appropriate conditions. I haven’t tested mine in anything tougher than straight-line winds of 20 knots or so, and it’s fine for that. Part of the issue in conversations of this type is the unsteady nature of the terminology; what has been deemed a “spare”, I would call a “secondary”, the anchor I would deploy were I to a) lose the primary or hit an unexpected bottom it didn’t like at all, or b) a second anchor for a two anchor set or a Bahamian moor. In the latter case, I’m not sure it makes a difference whether the second anchor is at the bow or the stern.
Hi Dick, John, Marc
on Pelerin we carry four anchors. Two Rocna’s (33 & 25kgs) a 30kg fisherman and a Fortress FX-23. The two Rocna’s are our bower and second anchor/bower back up. The fisherman we keep for kelp but quite honestly we think we might as well do away with it. The Fortress is a bit small, but is used as a stern anchor alone – where it works very well.
We have used Rocna anchors exclusively as bower anchors for over ten years now, both on my old working boat and now with Pelerin. We have spent literally thousands of nights at anchor with a Rocna. We have sat out storms at anchor in conditions where we would have been really nervous with an old generation anchor and have blessed the thing many, many times. During that time we have dragged twice, both times in extreme thunderstorms in the Ilha Grande area of Brazil. On both occasions this occurred after 180 degree wind shifts in 40-50 knots + and prolonged squalls. On both occasions we didn’t drag far, but the first time we ended up on top of another boat and had to shift and re-anchor. The second time was less serious, as we had more room. As a result we now have a policy of starting the motor and digging in the anchor again after a big wind shift. 99% of the time this works fine, but occasionally we have simply dragged the anchor with little resistance – and no, we haven’t been heavy handed with the throttle, either.
My guess is that when the plough of the anchor and roll bar are choked with solid mud the balance of the anchor is affected. I think that’s the most likely cause because there is little resistance to the boat’s movement, it feels almost like the anchor is simply sliding along on the base of the flukes. If that’s so, then surely the point is not in the correct alignment to dig in again rapidly. Of course, it might also be the case that the anchor is so choked with mud that there is some form of resistance to the passage of the anchor into ‘new’ mud. Without watching this underwater it would be hard to know.
I’d point out that in both cases where we dragged conditions were really extreme. I have no way of knowing how another similar ‘new generation’ anchor would have coped, but we’re glad that the Rocna coped as well as it did. I would never go back to any of the ‘old generation’ anchors if you paid me, as I know from many years experience that they are nothing like as good as the Rocna.
I agree with John that there are times when the Rocna may have an edge over the Spade – short scope, better holding power (perhaps) in soft mud, due to the huge fluke area. But equally there are times when the Spade (from all I have learned) will have an edge, too, notably in big wind shifts. Other anchors of the same style may have their advantages, too. But all of them can drag if thrown the wrong combination of circumstances – of that I’m sure. There is probably no perfect anchor.
Ultimately, the choice of a bower anchor should be down to being the best all-rounder. My guess today is that anchor may be the Spade. If we ever change our bower anchor it would only be to a Spade of the (approximate) same size. But we wouldn’t write off the Rocna which is an amazing anchor, and we’d certainly keep it as our back-up and number two, maybe number one in the right circumstances. For the moment, we know that we must take the extra precaution and dig it in again after a big wind shift, and we’d recommend the same procedure to anyone else who relies on one. Forewarned is forearmed.
Best wishes
Colin
Hi Colin,
Thanks for the well balanced and insightful analysis from a long time Rocna user. I agree with all points.
Hi Colin, John and all,
As to this discussion, I consider the short scoping attributes of a Rocna as far from compelling and in my anchoring world generally not an issue. I can think of no times this season where I would have wished for shorter scope nor did I reject any anchorage because I felt it would be too tight. In general, I suspect I would reject an anchorage that demanded short scope (either caused by land close at hand or a proximity of other vessels), because of the limitations on options if things heated up during the night. I think short scope is even less of an attribute if you have sized your bower to also be your storm anchor.
The other issue that would concern me is my mild, but palpable, anxiety when we leave the boat for long hikes or other excursions. Coming over the rise and seeing Alchemy bobbing safely at anchor after being gone all day is always a bit of a relief, especially when the weather has been unsettled. I rarely worry about the anchoring choices/situations if I am to stay on the boat, but know I am more concerned about the possibilities if I plan to be gone for long periods. It is then that I would really want an anchor that re-set without need for personal attendance.
Finally, I have been thinking and reviewing in my head, John’s comment that scope greater than 5-1 may be contraindicated because of the longer run-in distances possible in gusts and wind shifts. Although we have weather gale conditions on a 5-1 scope, I am clear that, given the opportunity, I let out more scope and have slept better for it. I suspect we “hunted” around a bit more with the additional length of leash, but not so I worried about it or even had it caught my attention. This may be as I use a very long and small diameter snubber (35 feet x 7/16 inch), but one could also argue such a light long snubber would contribute to flailing about. Bottom line, I like an increased scope and have noticed no drawbacks that concern me.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Thanks for a lot of good insights, as always.
On reflection, I think you are probably right that my 5:1 max scope thinking is a bit short. Having said that, I’m reasonably sure that with scope once you get past say about 7:1, more is not necessarily better.
Hi John,
Bear with me. When I disagree with someone who I know to be thoughtful and experienced, I always like to clarify the details and usually learn something. My take has been that more scope is always better when it comes to keeping a boat attached to the seabed.
My experience in gale conditions with 7-1 scope is that when seas and gusts combine to rear the boat back, the chain gets pretty close to 2-blocked: stretched link to link, with some degree of regularity. This translates to the anchor receiving a tug. Many times, anchorage circumstances dictate that I do not have the option of more scope and I have been always been fine (knock wood). When the option is there, however, I have always let out more chain (maybe 10-1 or more) and felt like the boat was more secure. I have the sense that there is significant chain near the anchor that is never off the seabed anymore. Therefore, the anchor is little disturbed and what tugs it receives are at the best angle of attack, anchor to seabed. At this increased scope, the chain is never (at least in gale conditions) 2-blocked and so is providing catenary dampening of the forces as well as the averaging of forces provided by the snubber.
I believe the argument against higher ratios of scope is that the boat is on a long leash and can therefore have longer run-ins till it fetches up against the leash/rode and making a more forceful tug on the rode when it comes to the end of the tether. I believe this to be the case, but, it is my take that the added security of more scope far outweighs the added pressure on the rode as the boat has more latitude as it thrashes around. My memory is that with a longer scope, there was much less likelihood of the chain becoming 2-blocked when the boat fetched up and that the catenary (along with the snubber) softened the forces. Moreover, and maybe telling in itself, we were not at all bothered by any increased movement on the boats part as we lived our life belowdecks. On the contrary, I believe us to be more comfortable at longer scopes and more secure in general.
Now I realize that one can’t always find an anchorage that allows for longer scopes, nor are all blows predictable, but when planning for a forecast blow and the choice seems to be a coin flip between a more protected spot where scope would be limited vs a spot with a bit more exposure, but scope can be added on, I opt for the latter.
I look forward to your thoughts.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
I guess, as we sometimes do, we will have to agree to disagree. All the data and calculation I have seen indicated that there is no appreciable shock absorption from catenary, at least at the normal chain weights carried by yachts. And my practical observation seems to support that. Therefore, my thinking, backed up by quite a bit of experience is that letting out more chain past a certain optimal point just adds to shock loads because the boat gets more momentum before she comes up short when a gust comes from a new direction.
Now of course the question then comes what is the optimal point? And I guess that depends on a whole bunch of variables, but generally I have not found any benefit in setting more than about 7:1.
Hi Dick,
Added to my above, I would say that we agree entirely on choosing an anchorage with more room when a big blow is on the way: https://www.morganscloud.com/2011/11/04/choosing-a-storm-anchorage-part-one/
This is a most fruitful discussion for us. Dick, you’ve said better than I could why 7:1 in a blow seems right to me in a way that 5:1 might (and I’m being careful here with the use of “might”) not. Our inclination is to avoid being too close to land and other boats and if the anchorage seems too tight on either score, or we know heavy weather and wind shifts might make it so, we would be inclined to stand out to sea rather than compromise on this point.
Colin, you can’t argue with success, and you’ve had mostly that, save for the two situations you cited. No doubt all credit to the Rocna on that score. You don’t write the nature of your rode (chain or mixed), the scope out in those extreme conditions, nor whether you have a waterline snubber or bridle on the rode , all factors I think, as Dick has pointed out, play important roles in that chimera of “ultimate holding power”. I would welcome your thoughts on Dick’s comment on those factors.
Hi Dick, John,
As a Rocna owner, I have been following this chapter with interest and this sub-discussion on scope. I believe you are both right guys, “it depends”. If I may relate a long story (apologies in advance) to illustrate why:
Many moons ago I was a young Navigating Officer, on a 1200 foot ship anchored on a calm night in Wellington harbour (NZ), plenty of scope. I was writing up the log just before the change of watch at midnight. I observed the wind was getting up, maybe 15 knots. Nothing alarming, but never-the-less knowing the reputation of Cook Straight and Windy Wellington, I rang the engine room for immediate standby and the captain under his standing orders, but no answer from either – strange! I checked my anchor bearings. We were fine, but I noticed the bows starting to sheer-off in some building gusts. I rang the Saloon for the Captain, in case he was there. No reply – stranger still. By then the ship was skating around her anchor, the swings getting greater with every oscillation. Mild concern set in (or maybe a bit more)… I rang the ship’s general alarm bells 7 times rapidly… nothing. RANG AGAIN… still nothing. Ship’s alarms are really loud, at least 75dB(A) by law, usually much more. Was I suddenly on a ghost ship?
The wind was gusting harder, perhaps 30 knots and my anchor bearings were changing, slowly at first and then I didn’t need the compass to tell me. Still no captain, still no engine! Relief, the second officer arrived on the bridge wide-eyed. I thrust a radio in his hand with few words, one of which was “dragging” and the others unprintable. He disappeared towards the bow. I sounded the ship’s main fog horn, 3 short blasts – “I am going astern”…nothing! THEN SEVEN OR MORE BLASTS FOLLOWED BY ONE LONG (I should have been seeing people scrambling into lifejackets, or lifeboats even by then) – still nothing! We were dragging in a remarkably rapid and straight line astern towards an ugly lee shore – I didn’t have time to calculate our ETA.
Finally, finally, a white faced captain, 1st officer and half the crew arrived on the bridge together (no lifejackets). The engine room phone buzzed and I called for main engine power – took an absolute age. The second officer called on the radio from the bow, “do we want the second anchor”? Too late – the stern of the ship was now inside Evans Bay (lucky the wind knocks were more frequent than the lifts or we would have come aground on the point). We can see from the bridge directly along Oriental parade towards the city (have a look on Google Maps if you are interested). At long last the Telegraph buzzes, we plant it full ahead and motor over the anchor, no time for niceties and drag the anchor across the harbour to its previous position.
It turns out everyone was in the officer’s bar watching a loud movie – they didn’t hear the phone, nor the alarms (the alarm speaker having failed). The engineers were handing over their watch in the changing room – less said on that the better! How lucky was I? Maybe why I never win raffles.
But what I observed has stayed vividly imprinted in my mind, as is often the case in times of emotion (positive or negative). The wind gusts were veering and backing by 30+ degrees as they came out of distant and different steep-to valleys to windward of us (perhaps 50 knot gusts by the time we got control again, relatively normal for Wellington). This preceded the anchor break-out, as the ship sailed off its anchor following successive swings, each more violent. Even though we had anchored many times in similar wind strengths, I believe on this occasion we didn’t have the right setup for the combination of sudden load with repeated change of direction, working the anchor out of the bottom like a hook out of a snapper’s mouth. With hindsight I believe the scope was too short (there is no snubber on a ship and the chain catenary is the only shock absorber), but hey, I wasn’t making very scientific observations at the time.
From this experience, I see our priority is to avoid the situation where the boat/ship can shock load our anchor from repeated and different directions. For some boats this may be mitigated by increasing scope, for some it may be limiting scope – I suspect each boat / ship will be different and even alter with conditions. Our current yacht seems to respond well to increased scope of chain (even 10:1) and a bridle from both bow fairleads (rather than single line snubber), but we haven’t been in any extreme anchorages.
Rob
Hi Rob,
What a great story, and so well told too, I was riveted and could feel my stomach knotting in sympathy.
And I think you nailed the scope issue: it depends: boat, location, gusting direction and strength, chain size, sea bottom type, and on it goes. I guess my worry was, and is, that the “more scope equals better” rule is, I think, too simplistic.
The other point I wanted to make was that I think too many cruisers over-rely on the shock absorption from chain catenary. In my experience, once the wind gusts are greater than about 35-40 knots, that benefit is illusionary.
Hi Rob and John,
Fascinating story, Rob. Especially with the good ending. Thanks for sharing.
As an aside, what a good example of how often it is a confluence of small events: broken alarm, loud movie, change of watch, which contribute to the making (almost) of a single disaster.
More to the topic; clearly the veering about in gusts was deemed to contribute in some large measure to the breaking out of the anchor and subsequent travels along the harbor. I think those with too short scope (as you felt was the case for your ship) for conditions often have their anchor break out in just the way you describe when a combination of seas, gusts and veering- about yank the anchor loose from the seabed. On the other hand, I have yet to hear reports of recreational vessels who felt that an anchor break out was attributed to scope that was too long (allowing for increased shock loads as there is more momentum built up because of greater distances traveled between gusts). I do believe that there is an increase in shock loads and momentum, but believe that the increased scope more than compensates, much more. Bottom line for me, with all the data and calculations you mention, I just do not hear, read or find reports of recreational vessels breaking out their anchor with greater scope ratios and attributing it to the increased loads referred to. Breaking out with short scope., for sure, longer scope break out is just not on my radar screen.
I very much agree, with usual anchoring scope ratios (5-1 to 7-1 or so), that chain catenary is an illusion when it comes to weathering gales. And I also agree, Rob, that boats lying to a 10-1 scope behave quite well (designs good for ocean passages probably do better in this regard), even when things get boisterous. When increasing scope to 10-1, it has been my observation that chain catenary does play a role in dampening forces (in gale conditions and along with the snubber) and as the ratio increases, the more of a role chain catenary plays in averaging forces. And this is one reason I increase scope over 7-1 when conditions warrant and opportunity allows.
I think it is always an issue being too formulaic and simplistic: ie, more scope is better. That said I look to reported evidence that more scope causes/contributes to anchor break out in either my own experience, reports in the media or shooting the breeze on the docks, and have yet to find any. Quite the contrary, most sailors, experienced or otherwise, first reaction to things heating up is to veer more rode. Now, I am far from saying that one’s first reactions are always the best, but there is a lot of history and experience behind this reaction.
My best to all, Dick Stevenson, s/v Alchemy
Hi Dick – Your last comment on first reactions and scope reminds me of the apocryphal story of a young trainee up for Maritime Board oral examination: Examiner (usually a “grey-bearded” Extra-Master Mariner) – “You are at anchor young man, the wind backs and increases to force 6. What would you do”? Trainee – “Why, I would let out more scope sir”. Says the examiner – “Ok good, the wind is now force 8, what will you do”? Trainee – “let out more scope sir”. Examiner “Ha, you are running out of options lad. It’s now storm force 9-10, you are dragging, what to do eh?’ Trainee – “Let out more scope sir”. Examiner – “where are you getting all this blasted chain from young man”? Trainee – “same place you’re getting all the wind from sir”!!
Rob
Because my bowsprit wouldn’t accomodate the rollbar of a rocna, I chose a SPADE on your recommendation for my Dana 24. Glad I did. It cost less than 1% the price of my boat, so I find it amusing that anyone would consider the price factor when buying an anchor. It’s not like you’re going to buy it many times, right?
I had a rocna on my previous boat (catalina 30) and was satisfied with it (inshore sailing east coast US). Only once did I drag, and then very slowly: because I was foolish to anchor off saquish neck in at the entrance of Plymouth harbor, an area with very strong current in a deeper channel. I’m assuming the current moves the soft sand. The anchor was fighting good and the dragging was slow. Not sure a SPADE would have been behaving better in these circumstances.
That said, it seems the body of evidence points to the SPADE being the best choice these days. IMO you should always select the best ground tackle, even if you’re not a full time voyager.
Hi Richard,
I too can never understand why cruisers give as much weight to price when selecting anchors as they do. And to make it even more perplexing, I often see a lot of expensive electronics on the same boat with a cheap and/or obsolete anchor.
Other people have mentioned it, but this important point should be emphasized!
The Rocna 33lb is being compared to the 33 PERCENT HEAVIER Spade 44lb. Thirty Three Percent!!! In John’s own words in a previous chapter, “bigger is not just better, it’s a LOT better.”
To me, it seems discriminatory, to allow such a biased test between anchors to radically change the recommendations of the author (whom I have a ton of respect for and love learning from).
Just looking at the Mason Supreme and Rocna tests, we see evidence that supports the theory that mass is critical in these tests. They are nearly identical, except the Supreme is 36 percent HEAVIER than the tested Rocna. It sets every time. Coincidence, maybe, superior engineering, maybe, but definitive test, certainly not.
And if you ever needed evidence of the spade failing, look at the earlier comment from Geir ove, who posted a video of a spade sliding in the mud. Proof that perhaps all anchors can and do fail at some point.
Although you have stated you have heard reports from other sailors of their Rocna failing, it seems that this video is the catalyst to change your recommendation, and to me, that seems unfair, until a proper test with equal weighted anchors, is performed.
Conor, while I certainly acknowledge the validity of comparing “like with like”, please consider that with its lead-weighted tip, the SPADE isn’t “like” in that sense. My understanding is that in terms of fluke area, it’s smaller than the Rocna. The lead in the tip has to form some of that extra weight.
Were a Rocna versus a Manson or even a CQR being discussed, the “like with like” equation would be satisfied. The SPADE’s lead tip, however, would seem to be key to its ability to orient well and bury quickly. That’s a qualitatively different approach than the quantitatively different observation you’ve made. The now-old-news Rocna metal-grade issue aside, I have no doubt it’s a very good design, and one that is now largely proven in the field. But that doesn’t make it without potential flaws, none of which may ever arise in your own sailing grounds or anchoring style. But some of us are looking for as comprehensive an anchor as we can discern, even while acknowledging that it, too, may drag under unusual conditions of ground, wind or current. Discussions like this one, particularly where there’s a high degree of offshore and distant anchorage experience, get us closer to that sweet spot.
Hi Marc,
I think you are right about the importance of lead in the tip to the SPADES’ all round performance, although I would take that a step further and say that the key is percentage tip weight, which is a result of the overall fabricated design, not just the lead in the tip. Anyway, as you say, the key to choosing a best bower is all around performance.
Hi All,
Several people have pointed out that the Rocna being tested was lighter than the other anchors. I totally get that. So does that mean a heavier Rocna would not fail? Who can say for sure?
But the key point is, as I write in the post, we are not dealing with just this video. If we were I never would have written this post or withdrawn our recommendation of the Rocna as a best bower.
This video is just one of three indicators that there may be a problem. The other two are the Practical Sailor testing that indicated a fail to reset problem and about 10 credible reports from people I trust of Rocnas dragging after a radical windshift. And some of these reports were with anchors that were substantially larger than any tested by SV Panope.
Does any of this mean that I’m absolutely certain that there’s a problem? No, of course not.
But the evidence is compelling enough, and the consequences of the problem potentially dangerous enough, that it would be irresponsible of me not to publish.
And I assure you that telling thousands of fellow sailors that there may be a problem with their anchor brings me no pleasure. In fact, I have been dreading this post for weeks.
And that brings me to another point. Thanks to all of you for the well reasoned and civilized way you have approached this discussion. To use a charming old fashioned expression, you are all true gentlefolk, in the most literal sense of the word.
John, Marc,
I think I under-appreciated how much you put your neck on the line, in the first instance, making a gear reccomendation to readers. So I understand more that, out of prudence, you want to remove any recommendations while contrary reports are starting to filter in.
I think we can all agree we would love to see a 44lb Rocna tested by Panope in the same conditions.
Hi Conor,
Thanks very much for your understanding. And yes, I would like to see a heavier Rocna tested in the same way. That said, as I say in the article, a reader that we trust implicitly has independently verified the failure with a much heavier Rocna, albeit without the camera that makes the Panope testing so useful.
I know that comparing a Rocna to a Manson Supreme will provoke bun fights, but I found this Panope test interesting: equal-weight Manson vs. SPADE. The phrase “ridiculous scope” comes up: https://www.youtube.com/watch?v=giDsoDHxG_c
John-
In the anecdotal, FWIW Dept., I would agree with Dick Stevenson above regarding scope. I would also agree that price should not be a deciding factor in ground tackle selection. We switched from a marginally effective 110lb CQR to an 88lb Rocna on our Able Apogee 58 (8′ draft, 52,000lb+/-). We consistently use 7-8:1 scope when initially anchoring and have never suffered any adverse issues with more rather than less scope and a 25′ snubber. (Often, after a power set with our normal scope, tight anchorages have required a more courteous 3:1 scope.) While I respect your video results, 2.5 -3.5kt speeds with much less than recommended scope represent the typical bareboat charterer anchoring method, not the seasoned cruiser’s approach (amusing until they anchor near you). We tend to deploy our all chain rode at approx. 1-1.2kts, allow the anchor to settle for a minute or so, then hard set to 3000rpm for a min. of 30 seconds. In over 150 nights on the hook with the 88lb Rocna in New England, Florida and the Caribbean (and hundreds more on a 46′ sloop with a 66lb Rocna from the Great Lakes to Nova Scotia and the Florida Keys) , including reversals in 40+ knot frontal passages and in many areas between islands where a 180 degree 2-3kt tidal current reversal is the norm, we have only dragged twice. In both cases it was “user error” as a result of being in a hurry. I have dived on the anchor many times after a CF passage or tidal reversal and been amazed that, in a variety of bottoms, the Rocna has reset in just a few feet without breaking free. While the Spade is a great anchor, the tests haven’t convinced me that a properly set Rocna with maximum allowable scope and a good snubber isn’t just as effective. Anchoring technique, inattention to the composition of the bottom and failure to visually verify the set (visibility permitting, we often use our dinghy and a clear bottom bucket) appear to be the largest contributing factors to boats dragging, even in relatively benign conditions.
Regards,
John Lubimir
s/v Patriot
Thank you John.
I appreciate your insights and you sharing your experience.
This whole issue has had me feeling a little spooked & it’s good to know that with decent technique the Rocna may still be a viable option for our primary anchor. We are not offshore cruisers but in our home ‘turf’ of the West Coast around Vancouver Island and North Coast, many of the anchorages are subject to significant tidal currents and reversals. Mud bottoms in waters not conducive to diving mean that we are always left wondering as to what our set really looks like and whether a reversal will result in a sudden drag. I don’t like the thought that we cannot rely on a well-set anchor to stay that way. We have a Rocna 25 kg on a Nordic Tug 37 (40′ LOA & 22000lb displacement). We have not yet had it drag even in some rather stormy / reversing conditions but with rocky inhospitable lee shores as the norm, there isn’t much room for a sudden loss of holding.
I would be willing to swap out the Rocna if necessary but probably need to do some of our own experimentation before we consider it to be an unreliable bower.
– evan
Hi Evan,
I think that’s a very good approach: observe carefully, do some testing, and make your own call.
I realize that this is an old thread now but thought I might report back on our experience…
I had one occasion when anchoring with our Rocna 25 Kg anchor in Prideaux Haven in Desolation Sound. I chose a very scenic location in a channel between some small islets with fairly strong tidal currents. Overnight, strong winds in the 25 + knots sprang up and supplemented the force of a 180 degree tidal current change. Out of the blue, the anchor alarm started sounding at 0200h. I jumped up to see that we had indeed moved a good distance from our original set; but, over the subsequent tense couple of hours in the streaming rain and wind I was reassured to see that we were no longer moving. We were nevertheless uncomfortably close to some rocky bluffs. The next morning, we moved the boat to a slightly less scenic but more sheltered location.
In this case, I am quite sure that the anchor had dragged and reset with the tide change.
The SV Panope videos would seemingly support the possibility that the Rocna may release and have trouble re-setting. Thankfully it re-set for us but it took something like 25 – 40 meters to do that. We were close enough to the rocks when it re-set that any more movement would have been disastrous.
We subsequently replaced the Rocna with a Spade 120 and have noticed that the Spade definitely sets more quickly and reliably. (My wife, a nervous soul, often comments on how reassured she is by the hard definitive set with the Spade.) A number of local anchorages where we could not get a set with the Rocna (weed bottoms and thin mud) have been no issue with the Spade.
We also find that when raising the anchor the distribution of the mud on the Spade is on the tip and not the back of the flukes as it was on the Rocna.
My only criticism of the Spade would be that much of the yellow paint was peeling off when new and after ~ 75 – 100 anchor sets, the galvanizing is abraded off in a few places: on the tip, one spot on the dorsal surface of the shank and at the eye where the shackle attaches to the anchor. We are seeing rust blooming where the galvanizing has been lost. (I plan to spray these areas with galvanizing paint.) I do think that the galvanizing could be better applied than it is…
That quibble aside, we are very happy with the Spade and happy that we made the switch.
-evan
Hi Evan,
Thanks for the report, really useful. There is still a lot of love for the Rocna out there, much of it blind, and the more of these reports we have the more likely it is that at the very least Rocna users will be aware of this rare and dangerous weakness.
And yes, I agree on the SPADE galvanizing, they definitely need to do a better job. On the bright side, it does not seem that the rusting affects the anchors utility, even over years, but it is annoying.
As to the yellow paint, I think it’s a pretty silly “feature” since it does not last long, and anyway the SPADE always buries the whole fluke, so what’s the point.
Hi All,
In rereading through this fantastically useful series of comments, as well as those on Facebook—I don’t answer FB comments due to lack of time, but I do read them—something had jumped out at me. Almost every Rocna owner loves their anchor, which is perfectly understandable, it’s a great anchor.
But almost every Rocna owner also says it’s never dragged on me…except when, and then gone on to list a couple of drag events and then excuse them with extenuating circumstances: poor set, poor bottom, chewed up bottom…
But here’s the thing. Phyllis and I have been anchoring with a SPADE for nearly two decades. Thousands of sets in some very hostile places with multi-directional gusting. And also in places that have been all churned up by other anchors. Places as diverse as it gets: Greenland, Baffin Island, Bahamas, UK, Chesapeake Bay, and on it goes.
And in all that time, the SPADE has never dragged once set, not even once. Now of course that’s not definitive proof of anything, but it is an indicator.
My own theory—shamelessly stolen from Colin Speedie—is that when the Rocna loads up with mud it then skates across the bottom on the large flat area on the fluke because the percentage tip weight has been grossly reduced by the mud.
On the other hand the SPADE has nearly double the percentage tip weight than the Rocna when both anchors are clean and I think this advantage gets hugely bigger when both are muddy due to the basic geometry of the two anchors.
A quick glance at this shot shows graphically the large flat area on the Rocna contrasted to the V’d back of the SPADE https://etugri87v3i.exactdn.com/wp-content/uploads/2011/11/JHH5-13426-Edit.jpg
The other aspect to this is that when the Rocna is unbalanced and skating across the bottom the dragging is very quick. On the other hand, on the few occasions when the SPADE has refused to set for us, it has only dragged very slowly with a great deal of resistance, even under the assault of our large engine and three blade prop and 3/4 power.
Does any of this make the Rocna a bad anchor? Absolutely not. But I do think that it makes the SPADE a better choice for Best Bower, where reliability when set is, in my opinion, the most important selection criteria.
Hi John
I just heard of an interesting trick that the schooners in Maine sometimes use for storm anchoring. They drop an anchor in a deep hole (one near here on Vinalhaven is 140 feet deep) and drop back to a water depth of 10 feet. That way, an anchor dragging has the chain and anchor dragging uphill for its whole length. Scope is way more than 10 to 1 and there is minimal skating around on the anchor.
I like that idea!
Hi Charles,
Well that’s certainly the best of all worlds, that is until the wind changes and the anchor gets pulled out of the wall from the other side.
Hi Charles,
Anchoring uphill such as you describe is pretty common in the Med, especially around Turkey, when combined with tying off to shore. The depths are such (and the prevailing norms) that free anchoring is often not a wise choice. With the right bottom, one can achieve impressive holding with little scope, especially when the winds get sideways and the forces multiply dramatically.
Always fun to hear what the big boys do.
My best, Dick Stevenson, s/v Alchemy
Hi John,
in your opening story you mention about a yacht being lost in Greenland and seem to infer that it was Rocna equipped.
The yacht concerned was Arctic Tern 1, and as can be seen in the picture was fitted with some form of plough anchor (I will not say CQR), and it was this anchor and another similar one that failed to hold her;
https://i.vimeocdn.com/video/531283178_1280x720.jpg
The replacement Arctic Tern is fitted with a Rocna, per
http://northwestpassage2014.blogspot.cl/2014/09/sv-arctic-tern-uk-arrives-nome-alaska.html#!/2014/09/sv-arctic-tern-uk-arrives-nome-alaska.html
so it would be best to amend the appropriate paragraphs
cheers
Alan
Hi Alan,
You may be right. As I said in the article, I was not blaming a Rocna for the loss. The point I was making is that an anchor that drags once set, even once, can have very serious consequences.
Hi Alan,
Further to my last. The yacht I was talking about was definitely not the yacht shown in the picture you linked to. The yacht I was referring to was a Saga 40 that we rafted with earlier in the summer. I have a pic from that time that shows a modern style anchor on her bow, not a CQR.
Hi John,
the story you tell appears to be entirely consistent with the events resulting in the loss of Arctic Tern 1 and rescue of its crew.
Hi Alan,
You are right, that’s the couple. We met them earlier in the summer of 2011, and in fact we rafted up with them at Aassiat a few weeks before they lost their then boat. But the key point is that the boat they lost in Greenland is not either of the two boats you show in photographs linked to in your first comment. The boat they lost was a double ended Saga 40. I even have a photograph of her rafted up next to us taken from the top of our mast when I was doing a rig check.
Anyway, none of this really matters because I never wrote that a Rocna was at fault. I quote from my original paragraph above:
My only intent in telling that story was to point out that when an anchor that is well set drags in a wind shift, bad stuff happens.
Hi Alan,
Further to my above. I just found an email conversation I had with Les Parsons shortly after the loss of the boat. Her name was “Islander” and, as I said before, she was a Saga 40, nothing like the boats in the photos you link to.