So let’s deal with snubbers, a subject that cruisers love to debate. The good news is that it’s just not that complicated:
Anchoring—Snubbers
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More Articles From Online Book: Anchoring Made Easy:
- Introduction
- 4 Vital Anchor Selection Criteria and a Review of SPADE
- SARCA Excel Anchor—A Real World Test
- SPADE, SARCA Excel, or Some Other Anchor?
- Rocna Resetting Failures and Evaluation of Vulcan and Mantus
- Ultra Anchor Review
- Specifying Primary Anchor Size
- Kedge (Secondary Anchor)—Recommended Type and Size
- Third Anchors, Storm Anchors and Spare Anchors
- Anchor Tests—The Good, The Bad, and The Downright Silly
- Making Anchor Tests More Meaningful
- We Love The Way Our Anchor Drags
- Things to Know About Anchor Chain
- Selecting a Chain Grade
- Anchor Chain Catenary, When it Matters and When it Doesn’t
- Anchoring—Snubbers
- Anchor Rode Questions and Answers
- Q&A: Hybrid Rope And Chain Anchor Rodes
- Anchor Swivels, Just Say No
- A Windlass That Makes The Grade
- The Perfect Anchor Roller
- Install A Wash-down Pump—And Save Money!
- Anchoring—Kellets
- Anchoring—Chain: Stoppers, Termination and Marking
- 20 Tips To Get Anchored and Stay Anchored
- Choosing an Anchorage
- Choosing a Spot
- 15 Steps To Getting Securely Anchored
- One Anchor or Two?
- Two Anchors Done Right
- Yawing at Anchor, The Theory and The Solution
- Yawing at The Anchor, an Alternative Cure
- How To Use An Anchor Trip Line
- ShoreFasts—Part 1, When to Use Them
- ShoreFasts—Part 2, Example Setups Plus Tips and Tricks
- ShoreFasts—Part 3, The Gear
- A Small-Boat Anchoring System
Great post as always. My wife and I were laughing that only cruisers could enjoy a long post on how to use a piece of rope …
Most of our experience is “low latitude” other than a recent foray into Alaska up to about 61N but all pretty tame compared to your experiences. That being said we were cruising full time for seven years and almost exclusively at anchor. As we enjoy kiteboarding and visiting more remote villages sometimes we anchor in less than desirable locations from a protection perspective.
After experimenting with chain hooks and bending a Wichard anchor chain hook we simply went back to using double rolling hitches. We do keep two chain hooks in rigging stores though as they were handy when our windlass died (another story).
We do two things differently that may or may not be worthy of consideration. Firstly, we too run our snubber over the anchor roller following the chain. As we only rig one large anchor I replaced the second anchor roller sheave with one that was just cone shaped (vice the standard hourglass shape of a roller sheave) with the inboard diameter the same size as the inboard end of the anchor roller sheave that the anchor rides on so there is no ridge for the snubber to bounce/slam/chafe across as the bow shears. The second thing is we generally rig a second snubber from a different cleat but also over the anchor roller that is about half the length of the primary snubber. This line is not loaded in the calms but only takes some of the strain in the peak loads causing the snubber system together to act as if it is a bigger line in the bigger waves or gusts. It also acts as a backup if we break the primary snubber (which only happened once). Quite possibly overkill but anything to keep the family home secure and facilitate some sleep on squally nights.
Thanks again for the great work you guys do.
Cheers,
Max
SV Fluenta
Hi Max,
That sounds like a good mod to the secondary anchor roller.
Hi John
Another objection to a water line bow eye is that on a vessel with any bow overhang the bight of the chain drops vertically downward and crosses the snubber as the snubber is attached to the vessel behind the chain. This of course chafes the snubber badly. In any but the quietest anchorage the lazy bight of the chain will chafe through the snubber in a remarkably short time – often after a few days of use.
An unmentioned benefit of a water line bow eye on a vessel with a bowsprit is that it keeps the snubber clear of the bobstay. However I long ago decided on such a vessel that it was better to put antichafe gear (usually a roller of some sort) on the bobstay and lead the snubber directly to the deck. If properly rigged, this system results in far less chafe than letting the slack chain cross the snubber and of course also allows the snubber to be let go from deck in an emergency, as you point out.
Hi Trevor,
Good to hear from you. I had not thought of that aspect, thanks for the fill on it.
We use a soft shackle to attach s Uber to chain.. easy to undo and will not slip. Brett
Hi Brett,
That’s certainly an option, but it does require retrieving the snubber in a tricky situation, just as I detail above, so probably worth remembering the rolling hitch option so you could use another line, just in case.
Thanks John,
Your comment about matching the break load of the chain and snubber make sense – but raise a practical question. Taking 8mm chain as an example, where 40 grade has break load of about 4000kg – this probably implies using a 14mm snubber rope? Have I got this right?
10mm chain would presumably need 18/20mm snubber?
This seems a heavier snubber line than shown in the photo.
Hi Nick,
We using 3/4″ (~20 mm) braid with about a 20,000 lb break load. Our chain is 3/8″ G70 that’s about 23,000 lb break. Our old chain was 9/16″ G40 at about 21,000 lb. At this level I think that the 3/4″ is close enough since I have never seen or even heard of good quality anchor chain breaking. That said, to really conform to what I said above we should go to 7/8″ for the snubber. Anyway, the basic point I was making is that using a snubber that has less than half the chain break load, as you often see, to get more stretch does not make sense. Better, if we want more stretch (I don’t) to make the snubber longer.
The snubber braid snubber in the photo is 3/4″. The three strand was 5/8″ that we used before I figured out the mistake we were making.
We had a snubber fail once when the rope parted where the rolling hitch connected to the chain. We thus modified our snubber practice to:
1. A primary snubber with a hard eye, attached to the chain with a soft shackle, and
2. A short, backup snubber of heavier rope, attached with a rolling hitch and cleated to a separate bow bollard (i.e. this is intended as a windlass saver).
Hi Alissa,
How heavy was the snubber that parted off, how big was the boat, and how hard was it blowing? I’m interested because even when we were using too light a snubber, before I learned better, we never had one part off, even in hurricane force gusting. Given your experience, I can certainly see your reasoning for a backup. In our case we have a massive chain brake to protect the windlass so I prefer the simplicity of one heavy snubber.
Hi John,
This was quite a few years ago now, so the details are fuzzy. She was a 13t mono sailboat, and the snubber we were using was approx 14mm 3-strand. I don’t recall the wind being anything more than fresh and gusty, but the achorage was a tidal passage and the boat was moving around awfully. It was also shallow.
Hi Alissa,
Thanks for getting back to me on that. I wonder if the line chafed on the bottom at the knot given that the water was shallow—food for thought.
Hi John,
That was one of our conclusions also.
We also considered the possibility that debris may have managed to get trapped between the knot and the chain as load came off and then started working on the knot against the chain. Conditions were such that we’d run over our chain in some lulls so load would temporarily come right off with chain up-and-down, then load up again.
Unfortunately, the cause of the failure remains speculation, but this was our reason to switch to the soft shackle for the main snubber; the idea that accumulated debris would be able to fall out easier, as opposed to potentially getting trapped against the chain.
Whatever the cause, this seems like a fairly infrequent issue, it seems, but this change for us came at very limited cost (we needed a new snubber anyway!) and with no real downsides.
Hello,
Can you use the 45 feet snubber with rolling hitch to use primary winch in case the windlass is out of order to weigh the anchor? In that case it is good to adapt the length of the snubber to the length of boat and deck layout?
Best regards.
Denis
SY Hibernia II HR46
We do that a lot in the Med when we are bow in with a stern anchor.
Hi Denis,
Not sure it would reach that far and have enough turns on the winch, but I don’t think it matters since once one is comfortable using rolling hitches, any line will work as a nipper(s) when retrieving chain in the case on a windlass fail. We have a couple of 60′ dock lines that would work fine and I recommend that any offshore cruising boat have plenty of spare line.
Regarding 30 feet of snubber, most of the time it sits in the mud and gets dirty and full of damaging grit. I went to 20 feet and am happier.
Hi Gino,
Yes, sometimes we shorten up in shallow water too. That said, I like to have the option of using 30′ and there is really no downside to doing that.
I use a beefy Dynema soft shackle to attach the snuber to the chain. Works like a charm.
Hi Marek,
That seems popular. For my thoughts see: https://www.morganscloud.com/2020/01/11/anchoring-snubbers/comment-page-1/#comment-289461
On Iemanja our Passport 40, we use double snubs off of separate cleats and passing thru chocks. Fire hose for chafe. Rolling hitches. We have never been a fan of metal on metal connections that are subject to loading. One slight kink or bend and there is big trouble retrieving the chain. While the double does little to eliminate hunting as you have stated, it does seem to slow it a bit at least with our configuration. More important to us is the old climbers adage…backup is good. Thanks for the great post as always John and Phyllis !
Hi Ernie,
That’s interesting. I tried a double, but never found any observable difference, but it probably depends on the boat.
Hello John,
A very timely article as this week I am in a discussion about this with another cruiser and comparing notes.
We are one of those boats with a tow eye, though we use it a bit differently. Our tow eye is roughly two feet off the water depending on fuel load. Our anchor roller is 11.5 feet above this tow eye and 6 feet forward of it on a pulpit. We run a pair of snubbers from our foredeck cleats, then over a pulpit roller and back down to and then through our tow eye. From there we secure the snubber’s end to the anchor chain.
When deployed the snubber assumes a “z” like profile as it turns 90 degrees at the tow eye and another 90 degrees over a bow roller. Our anchoring routine is to drop enough chain in order to securely anchor the boat in 35 knots of wind. Then we deploy one of our two snubbers.
We have them both marked so that we can easily deploy specific lengths according to the dictates of the wind gods. Both of our snubbers are 50 foot in length over all and 5/8ths diameter nylon brait. For sustained winds up to 35 knots the working length of our snubber needs only be 6′ according to a bunch of data from the manufacturer, but because of the way it is rigged it still needs another 20 feet in order to secure it to the deck cleat. In this configuration our chain’s catenary gets the equivalent of a 900 pound spring as you described in point 2 at the beginning of your article.
As the winds increase, we can increase this springing capacity easily by lengthening both the rode and the snubber. With both of our snubbers fully deployed that works out to over 9000 pounds of additional spring relief for our chain though we have yet to need it.
As far as how to best attach these snubbers we’ve been using chain hooks for the last seven years and each spring I find myself having to relearn my splicing. I think next year we’ll return to the rolling hitch. The main reason I used the chain hook for so long is because it could be deployed and retrieved with one hand and there have been a few times when that’s all I had. In rethinking this I feel I can still deploy it fairly quickly using the rolling hitch. I’ll have to work out the best way to get the bloody thing off the chain before it fouls the gypsy on retrieval.
Hi Edward,
Interesting but why make it so complicated? Maybe I know why. Seems like this is a high bow motor boat, perhaps a Nordhavn, and I have heard from my good friend Bob who has one that a lower attachment point is the only way to stop the boat healing one way and then the other as the anchor load comes on to the very high bow. The other thought is why keep the snubber short in light winds? Wouldn’t be easier to always deploy for heavy winds to save having to change when the winds gets up?
Bingo John, the boat is indeed a high bowed Nordhavn. We use a short length and choose to lengthen as need for three reasons. 1 It’s silent. 2 The chain hook can’t fall off. 3) It works in shallow water, no snubber on the seabed.
6′ works well in 35knots and under, which for us seems to be 90% of the time. Over 35 the snubber begins to stretch and you can feel the tension building as the snubber is saying ease me. Because the chain tension is all on the snubber easing out the chain is a simple matter. Lift the chain stopper. Manually pull out what is needed (no need to start an engine) and lower it into the water. Close the chain stopper and remove two hitches from the deck cleat and ease the snubber out another mark. If we need to dump the whole chain and leave we also have a 100′ polypro line attached to the bitter end so we can cut and run. It’s way more difficult to describe than to do it. If it takes more than 15 seconds it’s probably because I forgot to hold my mouth right.
One important point not covered in the comments is the midnight scenario of a boat dragging down on you and the need to get out of town in a hurry, without retrieving your main anchor. I’ve spliced 60′ of polypropelene line to the bitter end of our anchor rode. Now, if we need to make a fast exit I can jetison the entire rode and re-anchor with our 2nd bow anchor. In the morning the floating polypro can be found lying on the surface after a friendly discussion with the dragging boat that used to be to windward.
Roger Neiley
Saga 43 SoLunaMare
Hi Roger,
I will be covering the mechanics of slipping in another article.
Great idea, Roger.
Hi John, thank you for another excellent posting of advice with all the authority of extensive real world experience, on an issue I have been actively pondering. Just this one discussion has paid for the next 30 years of my subscription given the construction cost of the massively over specced lash up I was building myself up to, involving double bridles of anchor plait with many mooring compensators and bling hardware for connecting to the chain! Now my shopping list is a yard of anti chafe. 2500 words was perfect? Mike
Hi Mike,
Your comment has made my day, thank you!
Ok John, I got some questions for you here, regarding the fourth picture. I can see one mark where the arrow points to, I assume you line this up with the cleat when setting the snubber, right?
Then there is another marking just where the anti-chafe starts, I suppose you use this when replacing the anti-chafe sleeve. And if I get your habits correctly I would bet my left hand that there is another marking at the outer end where you are tying the inner rolling hitch, right?
But please, please enlighten me what the plastic ties on the chain are for, I mean those three just above the W/L.
Bet you anything they’re to mark 30 feet (or metres) of chain out, depending on the boat’s units
We only use 80′ of 5/16″ chain that is spliced to 250′ of 3/4″ three strand, but normally anchor in +/- 10′ of water and deploy around 60′-70′ of chain with a 20′ snubber using a chain hook and eye splice on a bow cleat, with a chafe guard of course. I do have a 30′ snubber line as well. I like the rolling hitch concept and think I will modify my setup. I always thought I could let the snubber go if necessary in a big blow and let out as much three strand as needed, but I would need to retrieve some chain to relieve the snubber load, meaning starting the engine and using the windlass, etc. I see your point about the simplicity of a regular cleat hitch instead of an eye splice. Thanks as usual John!
Hi David,
Glad it was useful. It took me years to realize that a cleat hitch was safer—I get there eventually!
Hi David, John,
Sorry, I may have the wrong understanding of your process, but reading in the post and comment above sets off some alarms for me in regard to easing a snubber under load using a “regular cleat hitch”. Easing any line (big or small) under extreme loads is fraught with danger for the rope handler, doubly so when the line is nylon and stretching under the shock load of waves and / or wind action, such as in this scenario which may be on a lively foredeck in the early hours and with pouring rain.
The traditional multi-figure (8) cleat belay (John pictures in his post) is known for staying hitched, which is why it is so popular. But it is not great at being eased under load – it stays hitched even as you remove a number of (8)s refusing to ease, but then suddenly as another (8) is removed, the rope can jump at great speed usually when the line handler is changing their grip, or position. This is especially true for small radius cleats like those pictured, in my experience. I have personally seen broken limbs from lines jumping (and have fractured a finger myself) – and that’s when the lines are being correctly handled. An unwary crew member, forming a bight in their hand or around a leg say, can or will lose a digit, or far worse.
A safer belay for easing under load is what NZ Coastguard teach and I understand use on their vessels, which is remembered by (the NZ toll-free dial prefix) “0800” – or a loop (0) followed by a single (8), followed by two further (0s). If in waves a locking (8) hitch can be added. I believe the first loop helps this belay to be eased on the cleat safely with the single (8) above easing, rather than jumping under load with the top (0) controlling the rate of ease.
That said, if in a situation where there was significant load on the snubber and we were needing it to be slipped, WHATEVER the cleat belay, we would endeavour to remove the strain before easing it out first. Which is simple in this case, by taking up the slack on the chain first using the windlass (AND have the engine going to ease the strain on the windlass if needed). Ropes under load are really scary.
Br. Rob
Hi Rob,
Sure that makes sense. That said, this was a post about snubbers not cleat hitches so I did have to stop somewhere…2300 words. Although I’m sure your way is better, I do have to say that I have never had a big problem easing a standard cleat hitch under heavy loads and this on a 25 ton boat. Also, the cleat in question is hardly small. We upsized them some years ago and if memory serves it’s some 12 inches long. I think it just looks small to you because that’s 3/4″ line on it. Also, if you look carefully at the shot, I’m pretty sure there’s a full turn before the first 8.
All that said, I certainly agree that loaded lines should always be treated with respect.
One other thought from your comment. Probably better to use braid because it’s less likely to jump and go under load like 3 strand can. Just thought of that.
Hi John,
The radius I was referring to was at the ends of the cleat, not the length. I was comparing them with commercial vessel cleats from my days as a navigator. The bigger the radius, the smoother the ease is likely to be in my experience. It’s the turns that provide the grip – not so much the lengths.
Interesting thought about braid being better than three strand and you are surely right with new rope. Although when braid gets worn, with sun and salt degradation too, the surface becomes abrasive and loses that waxy outer layer which would aid safe handling. When I fractured my finger I was easing a braided rope and trying to remove one turn too many.
Rob
Hi John,
This is a very reasonable recommendation. We do a few things slightly differently but the differences are really a matter of preference. The one thing that I will add is that not all nylon is made equal, this is a place where you want to buy decent line. Of the brands that are commonly available in North America, New England Ropes is probably the safest bet, I also like Novabraid but it is less available. If you compare the elongation properties of either of these to many other brands including Sampson which I buy a lot of lines of other materials from, they come out much better.
The biggest difference is that we attach to the chain with a soft shackle. It is very secure and a little faster, a slight preference for me but far from a night and day difference. You still should know a rolling hitch so that you don’t need to worry about casting off snubbers and running out of pre-spliced snubbers and soft shackles. By the way, to your comment above I have no problem casting off a snubber to increase scope attached this way just the same as you would attached with a rolling hitch, we have never had one come undone in all sorts of trying conditions.
In the compromise of boat design, our boats bow ended up with not great leads for a snubber due to being chafe prone. So we use 1 size down dyneema strop hitched with splices to the end of the snubber so that the nylon starts just over the bow. This is obviously more complicated and doesn’t allow you to adjust the length of nylon but works fine for us (we do carry 2 lengths of snubber). While I would love to redo the bow to eliminate chafe and cleat the nylon directly, we would introduce several other issues in doing that and the dyneema seems the best overall compromise to me for our specific boat.
By the way, once we got all of this sorted out, we have never broken a snubber including in a few named storms and several nor’easters. I have broken snubbers but it was always the result of being too small diameter, too short and/or a chafe point. We now replace the nylon and soft shackle at 5 years (we are not full time, we use them ~70 nights a year).
Eric
Hi Eric,
Good point on the rope. I too like rope from New England Rope, and Novabraid.
Also using Dyneema for a leader to solve a chafe problem is interesting. We all have to make compromises to allow for our boat’s limitations and that sounds like a good one.
Hi John and Eric,
I had to come up with Erics solution on my commercial cats years ago tying to an exposed pier every night. We can only run short lengths of nylon for dock lines into chain loops arounds the pier timbers. The nylon and the chafe guards, where they went through hawser, would both be eaten up in a couple days no matter what we did due to the sawing action. Also very loud. In fact, the aluminum hawser needed replacing twice as it was sawed through over time. The solution was to splice a loop into the nylon before it entered the boat and then splice a good sized length of covered dyneema or such into that loop. The dyneema comes through the hawser and is cleated as appropriate. As the load comes and goes the nylon takes the shock and stretch but the dyneema just sits there. No sawing or squeaking. And it needs no chafe protection since it’s not sawing. These set ups now last us 6months to a year vs. days. Applying this to your anchor snubber would still allow you to cleat, lengthen, retrieve etc. Additionally, if you are forced to go over the rail instead of the roller, as I see some cruisers do, it won’t saw through your boat.
Hi Kevin,
Sounds like a good system. We converted to Dyneema for shorefasts some years ago and I too have been amazed by how little it chafes.
Hi John,
Agree on all points.
Some random thoughts:
All knots benefit from having the knot tightened up by hand. The rolling hitch seems to benefit more in this area than many knots as they will “roll” over themselves if left loose and then loaded up. I believe some of the hesitation among many cruisers to use and benefit from this knot’s immense value to cruising sailboats derives from a habit of not firming up knots.
For those who wish to consider deviating from John’s bulletproof advice, I add a turn on my rolling hitches before and after the hitch, thereby only necessitating one knot. This knot, well drawn up, has served Alchemy for almost 2 decades of cruising.
I also run my snubber line right out over the roller next to the chain and have never used chafe gear over the roller and next to the chain and have never experienced chafe in this area.
Finally, 2,300 words is actually short when one considers that you are not only suggesting solutions but sharing a thinking process that can be applied to most every choice that comes up on a cruising boat.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Good point on the importance of tying a rolling hitch tight.
How serious is the point loading using a chain gripper? Mine is a claw that grabs the chain around the link, not a “hook.” If point loading is a serious issue, I might go for a rolling hitch approach. But there is no more problem extending the snubber attached by chain claw than one tied to the chain. You just add line at the boat end. And I like to take the setting strain on a short snubber and the chain claw is really quick to attach. Don’t want to use the windlass to take the strain and in my set up, there is no good place to place a chain stopper.
Hi Terence,
I really don’t know how bad point loading is, but it should be less bad with a claw like yours. That said, give the rolling hitch a try before you write the idea off. It takes about half an hour to learn the knot well, but after that it’s very quick and the big benefit is that it does not fall off when not loaded.
And sure you can extend the snubber when you need more scope, but there are two drawbacks:
On Snowball the snubber leaves the boat through an extra roller situated forward of the chain roller, so there is absolutely no chafe between chain and snubber. I hook a spliced eye over one bollard (will definitely change that to belaying it properly ) and belay the chain on the bollard of the opposite side. That way, if the snubber should brake, the windlass is still not under load. So everything is fine, except that the snubber is way too short to provide much of a springy action. I could use a longer snubber of course, but if I’d let out the recommended 10m, it would render the same length of chain useless, wouldn’t it ? On my 33 ft boat I carry 40 m of 10mm chain, so if I’d let out 10 m of snubber, a quarter of the heavy chain wouldn’t contribute to holding power. The only way I see around this is leading the snubber along the length of the deck and securing it way aft. That way I can use almost all my chain where it does its job and still have a long enough snubber. Do I miss something, or what are the thoughts on that in the community ?
Hi Hans,
Contrary to general opinion, the weight of the chain does not contribute to holding power, so no problem letting out more snubber. And even if the weight of chain did make a difference, I think, it would still be making that difference with 10 meters of snubber since the weight of chain between the boat and the end of the snubber would be still acting on the point of attachment.
Here is the the maths, thanks to Eric Klem, to show that catenary does not contribute to holding power, or at least not when it matters: https://www.morganscloud.com/2018/12/10/anchor-chain-catenary-when-it-matters-and-when-it-doesnt/
Good to hear that you have that added roller forward of the chain. This is a very good, but very rare, configuration not only for a snubber but also to bring a mooring pennant aboard without fear of chafe on the anchor—our boat is set up the same way.
On our 35 ft boat we use climbing rope as a snubber. This provides plenty of shock absorbtion and damping, more damping than i would expect from a nylon line. It doesn’t normally come larger than 11mm so not suitable for larger boats.
Because our anchor rollers don’t have a particularly smooth lead we have tended to used the fairleads instead. However this does cause chaff between the snubber and the bight of chain. I have just switched to running the snubber over the 2nd roller. Time and will show if this works better chaff wise.
we also use a 2nd short snubber on deck to protect the windlass just in case.
Hi Dan,
Just to clarify, climbing rope does provide more spring per foot, but it does not, as I understand it from Eric, provide any more damping. Both climbing rope and nylon rope are springs, not dampers—they don’t remove any appreciable energy, just store and return it. And assuming that one believes, as I do, that too much spring is detrimental there is no intrinsic benefit to climbing rope, other than more stretch per foot. The other issue with climbing rope is that it’s not usually rated by break load, so hard to spec in this application. I also think I’m right in saying that climbing rope loses strength quite quickly with load cycles. I’m no climber but I think I’m right that climbers retire their ropes after a given number of falls, so I wonder if climbing rope does not lose strength more quickly when cycle loaded than nylon? Don’t know, but would want to find out before using it as a snubber.
That said, I’m a huge fan of climbing rope for things like tethers which can be retired after being heavily loaded.
Thanks for your reply John. You are correct. Climbing ropes are tested and rated very differently with no brake load so hard to spec. They are rated for a maximum number of falls. These are very extreme falls, much more so than typically experienced climbing. My climbing ropes have all been retired based on length of service not number of falls. I don’t know but would expect other ropes would fail earlier when subjected to the same repeat fall tests. To my mind climbing ropes are designed to absorb the energy from a fall/larger load and limit the maximum shock force experienced by the climber, similar to what we are trying to achieving with a snubber.
Having said all that. If I hadn’t had some climbing rope lying around to use I may have picked up a length of nylon instead. And for a lot of boats climbing rope is simply too small.
It works for me and maybe is a good option in shallow anchorages where snubber length needs to be shorter to stop it rubbing on the floor where more spring per foot become useful.
Dan
Hi Dan,
Sounds good. Clearly you know what you are doing with the stuff. I just wanted to make sure that others who are not climbers understood the issues with DCR.
Hi John,
Thanks for another great article!
I just wanted to let you know I will be anxiously awaiting your article about hunting while at anchor or a mooring. We have a Kadey-Krogen 38 Cutter that acts like she doesn’t like being restrained! Right now I am considering a riding sail.
Best regards,
David
Hi David,
I will get to it, but a lot on the schedule right now. In the mean time, you are on the right track with a riding sail. Check out the work Drew is doing over at Practical Sailor on them.
John,
Sounds good. Thanks!
David
Very nice. A few comments, in no particular order.
Climbing Rope Strength. Although not speced by strength, they are about the same strength as a same-size nylon rope of the same diameter (I have broken on a load cell many in testing). A typical 10-11 mm rope is 6000-7500 pounds BS.
3-Strand. I have seen 3-strand rope unlay just a little and twist the chain over it under load. It depends on the lay. As a result, the snubber nearly chafed through in a single night at ~ 20 knots. Just something to be aware of.
Thin Snubbers. I generally used a snubber of about chain strength. However, I did have a skinny snubber for anchoring in really soft mud. I really wanted to minimize the force.
Point Loading by Hook. Unless there is something very wrong with the snubber design, you will be operating at less than 1/3 the WLL of the chain. This is n part because the WLL of nylon of equal strength is only 1/2-1/3 that of chain. Finally, chain is always point loaded. Thus, although point loading by a hook has often been brought up, I am not aware of an engineering argument or evidence that supports that a hook at 1/3 WLL has any effect.
Hose. Yes, I’ve tested that one. Chafe Pro is the better choice. It also lasts longer than hose.
Spring. Yup, Klem is right on that one. If it were an energy absorber, think of the heating! I’ve done bunch of testing on length and its affect on yawing. Obviously there are a LOT of boat specific variables, but there seems to be a sweet spot between 30 and 60 feet where forces are minimum. The corollary, curiously, is that limiting stretch of a rope rode can reduce yawing. For example, with a rope rode you use a chain leader, and that reduces the amount of nylon in the system. (There should always be at least 30 feet of rope over the roller or none, to avoid over working that rope. 50 feet is better.) In my case, now that I am using rope rode (last boat was all chain) I use a Dyneema bridle; this farther reduces yawing because the bridle cannot distort to one side, and it reduces the length of nylon. You can also use an oversize nylon rode, which reduces stretch and increases strength and wear. The result is a nylon rode with controlled stretch characteristics.
Some have suggested polyester. Unless you have a LOT of chain out, don’t. It rides like a jackhammer.
Another timely and excellent post. I am glad I renewed! I was surprised that you leave the line next to your chain on the roller or on your 2nd roller. But then I saw your bow and realized that the thing is totally built in. What about our poor soles that have ours bolted to the bow essentially cantilevered over the water? I was told that this put excess stress and it is best to put it though a fairlead and onto a cleat. Also , doesn’t the snubber ever jump out out he roller?
Hi Timothy,
I think that Drew is probably right that the load from the snubber on the bow assembly is less than the load when breaking out the anchor, so probably not a huge worry. And no, we have never had the snubber jump out of the the roller. I really can’t see how it could with the weight of the chain hanging on it.
The leverage question depends on the boat. But if you consider the angles, what crushes cantilevered bow rollers is breaking out a stuck anchor (sharp vertical snatch against a short, tight chain), not anchoring loads (slight angle, nylon in the system). I’m willing to guess many (not all) anchors see more force during breakout from under a rock than at any other time in their lives.
You should have a sturdy pin or other strong means to restrain the rode in the roller.
Hi Drew,
I agree on the need for a pin with all rope rode, but have never though that it was required with chain, and indeed we have never had a problem with chain jumping out of the roller.
The only two situations where I have heard of the rode jumping out of the roller assembly are a mooring, where boats can pitch violently, with the rope led from straight ahead by the float, and sea anchors, where again, the rope is pulling from straight ahead. Yes, totally different from the ground anchoring, whether chain or rope.
I had to laugh at your 30’ snubber. Here in Australia it is rare to anchor in more than 8m of water, usually less, like 3-4 m. We like the snubber for reducing chain noise (rumble) and whatever shock absorption we can get on 10’ of nylon. In some of the dodgy anchorages it seems to help the anchor stay buried.
We will be shifting to a rolling hitch; great idea. I’ve never liked the various chain hooks. The best grabber was the slotted plate from Sea Dog https://sea-dog.com/groups/2526-chain-gripper-plate but it suffers from many of the problems you discussed.
Actually, the best chain plate design (IMO) is this:
https://4.bp.blogspot.com/_fDLXryKUnCE/ShtN7OTGWkI/AAAAAAAAACI/ZE8zh1tvPiM/s400/Bridle+Plate+on+tramp,+low+res.jpg
It’s home-built, but it’s as strong and the chain and won’t fall off. That said, I also use everything from a rolling hitch to Dyneema slings. The only method I don’t like is a common chain hook.
I’ve used 30′ of snubber in as little as 1.5 meters of water, though more commonly 2 meters. In fact, in shallow water is where you need it most, since you have no catenary and steeper chop. The trick is to anchor the snubber to the mid-ships cleats, which works fine with careful routing and good chafe gear.
Hi Drew,
Good idea on taking the snubber aft in very shallow water.
Ok. I took your advice. Didn’t want to ‘cause I think the tech solution is cooler. But $500 +. Have spent two weeks of four up here in BC, Canada. This rolling hitch just works. Simple, no frills , no worries. I think this is the biggest unkept secret that nobody wants to accept. Thank you Attainable Adventure.
Hi Timothy,
Thanks for the kind words. Isn’t interesting the way we tend to naturally gravitate to more complex and expensive solutions. I know I constantly must fight that tendency. Might be a guy thing!
John
Thanks for a valuable article. This may be a stupid question, but if you are using 30′ of snubber and tying it to the cleat at the bow, how does this work in a shallow anchorage? And doesn’t it impact on the value of having chain on the bottom? What am I missing here?
Hi Douglas,
Not a stupid question at all. The snubber knot does drag around on the bottom and get a bit muddy, and I guess over time it could chafe, although we have never had that problem. However it does not seem to have any negative effect on anchoring efficiency. After all the same amount of chain is in play here, it’s just that the snubber is parallel to that.
All that said, if we are in a really shallow anchorage and not expecting much breeze we will sometimes shorted the snubber up to keep it cleaner. Of course, if the breeze comes up, we can always ease it back out.
Totally buy the argument that you need a sizable snubber.
But a bit unclear on how the 30′ of snubber is reconciled with the necessary amount of chain.
Let’s say that you are anchored such that without a snubber you would put down 30m of chain. And now you are going to use a snubber. Do you still use 30m of chain? This would give you about 60m of radius from your anchor which would be a lot in any crowded anchorage. If not 30m of chain then how much? You are not using snubber to replace chain completely so…?
Hi Peter,
The snubber does not change the required scope, it’s parallel to the chain. So if we need 30 meters:
Aaah
Thanks )
With regard to “The snubber should be nylon and sized to have the same break load as the chain”
A couple of things occur to me.
Many thanks for a superlative resource.
Hi Peter,
Answers:
They key to all three answers is the same: Contrary to popular opinion, more stretch is not better.
We just need enough to absorb jolts, which, from my observations, is not much at all. Past that more stretch actually makes surging around worse and increases load. That said, the exact amount of stretch is not critical.
Bottom line, the recommendations in the above post have worked fine for ~2000 anchorings including several in hurricane force multi direction katabatic gusting. Or to put it another way, it works, so no need to over think it.
Many thanks.
On the point of break load I read it but when I tried to apply it the results seemed counterintuitive so I wanted to check.
Here’s the math I did.
The chain I ordered is 13mm Katten Walder
It has a break load of 177 Kn
now if we follow your recommendation that the snubber has the same strength
(https://www.ashimori.co.jp/english/product/sanshi/rope/pdf/rope%20catalog.pdf)
that leads me to rope rode of approximate 33mm diameter which is about 1.3 inches thick with 40m say weighing 56KG or 124 pounds.
If I double check this on Jimmy Green
(https://jimmygreen.com/content/65-mooring-ropes-break-load-chart)
177Kn = 177 * 101.9716005 Kg = 18048 Kg
The only 2 lines that they supply that meet this spec appear to be Liros Anchorplait Nylon and Liros Superyacht Dockline both of which have diameter of 32mm
And this is very similar to the calculation above which is reassuring.
The all seems to make sense but that is a huge rope isn’t it?
Please excuse my naïveté but that is why I’m here 🙂
Hi Peter,
How big is this boat? That is huge chain! Also I’m not really a fan of SS chain, so I have not worked through any of this for said chain which is just about double the strength we used on our 56′ boat.
72ft
I don’t think 13mm is that huge surely. The original chain was 14mm galvanized. I think this is the standard size delivered with these boats.
Hi Peter,
It depends on the grade of the chain but half inch chain in a grade that strong would imply a boat in the 60-70 foot range and about 35 to 40 metric tons (rough guess) so for a boat under that it’s overkill and will put way too much weight in the bow.
And you still have not told me what boat this is. Without that fundamental I really can’t help further.
As I said above. It is a 72′ boat. An Oyster. Approx 55 tons.
Hi Peter,
OK, in that case I would still match the chain strength. With Novagold that would be 1’1/8. Big boats need big gear, no way around it. And in fact the bigger the boat the more important to not undersize anything since something breaking has exponentially worse and more dangerous results.
A key thing for any big boat owner to remember is that our bodies do not scale with the boats we buy so what would be just a painful bruise on a 12 ton boat will kill on 55 ton boat. Also, on the 12 ton boat we can use muscle to solve a problem after something breaks, on a 55 ton boat that’s not an option.
Bottom line, we need larger safety margins on big boats, not smaller.
Good advice, thanks
If we apply the same calculations to your G70 chain the math suggests you need 1 inch snubber. Is that what you have in your boat?
As stated in the post, 3/4″ which is pretty close : https://www.novabraid.com/rope/novagold/
I guess it could be argued that we should have 7/8″ though. Might be good too to have the added strength against aging.
John, Looking at the knot you are to tie onto the anchor chain, you call it a rolling hitch. Looking at it and then a youtube video of how tie, it, it looks just like what we used to call in boy scouts a taut-line hitch. Do you know if that is correct? That is indeed a very easy knot to tie. I’ve used it many times in other applications.
dj
Hi David,
Yes, I think it’s the same knot: https://www.netknots.com/rope_knots/tautline-hitch