Anchor Angst (John, 07/2007)

The other day I was idly paging through the posts on a cruising forum about anchoring and marveling at the level of energy and emotion, not to mention the sheer volume of posts, that this subject seems to elicit. I have to say that my first uncharitable thought was "I have to write about this stuff—that is what I do. But don’t these people have lives."
 

Update on Our Thoughts About the Luke Fisherman Anchor (John, 05/2007)

Up until we bought our 120lb (55kg) SPADE anchor in 2002, our 150lb Luke Fisherman anchor, that we affectionately call 'Big Bertha', was our anchor of choice in kelp and rocky bottoms like those found in Labrador and Greenland. We had our friend Frank Luke customize it to speed up assembly and kept it on the aft cabin top from where, with practice and using halyards, we could launch and retrieve it at the cost of about 30 minutes of hot sweaty work.

However, since the change to the SPADE, we have not had to set the Luke once, despite having made a voyage to Svalbard, a trans-Atlantic via Iceland and Greenland, and a circumnavigation of Newfoundland, while anchoring about 150 times.

So this begs the question: Do we stick with our original recommendation of “don’t leave home without a Luke Fisherman Anchor”?

First off, I think there may still be a bottom type where the SPADE would fail but the Luke would succeed. I’m thinking of about a 5 to 10 foot thickness of kelp that would compress under the weight of an anchor to say 2 feet. Under this there would be rocks imbedded in a thick and sticky mud—glacial flour generated by glaciers. To get securely anchored you would need to get a fluke down into the mud, through the kelp and between the boulders. Even the largest SPADE will only have a maximum fluke penetration depth of 12 to18 inches and if it does not get to the mud very quickly, it will then foul with weed balled in between the stock and blade and have to be retrieved and cleaned before another attempt is made.

The Luke works well in this kind of bottom because it lands immediately with most of its weight on the tip, due to the cross bar, and then has more reach though the weed to get down to the mud. The Luke’s relatively small and pointed fluke will easily separate the weed and dive between the stalks and rocks to get to the mud and it is unlikely to foul due to weed balling. Once an anchor is through all the weed and rocks, the mud is actually very good holding, so that the Luke's relatively small fluke surface area is not a problem.

So I think our new recommendation would be: If heading for Labrador or Greenland, a large Luke is probably a worthwhile investment as a backup to either a SPADE or a Rocna primary. But if the high latitudes are not on the agenda, we would make the spare a second Rocna or SPADE since they will have much better holding in mud or sand than the Luke due to their much larger fluke area for a given weight.

On Morgan’s Cloud we have kept our Luke, but moved it below.
 

Why We Don't Trust Moorings and Do Trust Anchors (John, 2007)

People are often surprised and even a little hurt when we turn down their kind offers to use their moorings in harbours we visit. They are even more perplexed as they watch us go to the trouble of anchoring outside the mooring field, often in a more exposed location. Here is an example of why:

Recently I have been trying to get a mooring put down in a sheltered inlet in Nova Scotia that will be heavy enough to withstand fall storms and even a hurricane. The first person we contacted, a reputable diver who does many of the moorings in that inlet, suggested a 2000lb (900kg) concrete block for our 26 ton boat. He said that was the heaviest weight he uses.

Now let’s think about that for a moment: Concrete loses half its weight in water and a block has virtually no form drag, so we are talking a total holding power of 1000lb (450kg). That is much less holding power than a good pattern 25lb (11kg) anchor provides. Would you trust your 56’ boat and home to a 25lb anchor, even in settled weather? I know we would not. Sure, when the block sinks into the mud the holding will go up, but not that much, and if the block moves at all from the snubbing of the boat, that benefit goes to zero.

I’m not trying to dump on the diver, particularly since, after a bit of discussion, he agreed that a lot more weight was required for our boat. But the point is—I know, you thought I would never get there—that many, maybe most, of the moorings in that inlet are at best 2000lb blocks.

Contrast that with our 120lb (55kg) SPADE that I would conservatively estimate can, when well set with plenty of scope, withstand a drag load of well over 8000lb (4500kg). That even makes a 1000lb (450kg) mushroom anchor (considered a heavy mooring weight on the east coast of the USA) look pretty wimpy. Even if it does move a bit, a good anchor, like a SPADE or Rocna, will reset itself, whereas a concrete block or mushroom anchor, once moved at all, will exert little more drag than its dead weight in water.

Finally, I know that our chain is in good condition and all the shackles are properly wired. Given all that, we know which ground tackle we will choose to give us a good night’s sleep.

Further to the above, when bad weather threatens we are always amazed how many cruisers pick up a mooring they know little or nothing about rather than heading for the security of a snug cove and their own anchors.

The Truth is Out About Old Style Anchors (John, 2007)

There is an interesting comparison test of anchors in the October issue of Sail magazine. All the usual anchor suspects are put through their paces but what stands out is the very poor performance of traditional anchors, particularly the CQR, against more modern designs like the Rocna and SPADE. The testers at Sail were surprised. We were not, having dragged a CQR around half the periphery of the Atlantic basin. See Gear failures & fixes for more about our experience with the CQR.

If you are using an old design anchor and particularly if it is a CQR, we strongly recommend that you upgrade to one of the newer designs. It is one of the easiest, cheapest (in comparison to many other upgrades) and most effective ways to increase your safety and enjoyment of cruising.
 

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