Anchor weights - advice sought

[stiknstring]

Grateful for any views on the weight of anchor desirable for prolonged stays at anchor in North Grenadines area post - ARC this year. I already have a Delta 16 kg (on a 40' boat displacement 19,000 lbs), but am deliberating whether to consign this to service as a kedge anchor and buy a Delta 25 kg as the main bower.

Just wonder if this is too heavy? Would another 16 kg do the job?

Any views welcomed. Thanks in advance

Stiknstring

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[Talbot]

what size chain do you have - as this is also critical to the holding power. I assume that you have a windlass of some form already. I would have choosen a delta of at least one size higher than the 16, as this is the anchor I am considering for my boat which is smaller and lighter than yours (and I have 10mm chain as well)

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[Joe_Cole]

I wouldn't claim to be an expert but I have always been under the impression that there is no such thing as an anchor which is too heavy.

FWIW I think that it is regarded as good practice to have a different types of anchor. If your current Delta is to become your kedge, then it may be worth looking at something different up front.

I'm sure though that others will give you the benefit of real experience!

Joe

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[wagenaar]

From what I have read in the last couple of years there seem to be at least two new types of anchors available: The Spade Anchor and the Bugelanchor, which both have received a lot of acclaim. The website of the spade-anchor gives the reasoning behind its design and concludes that the form is more important than the weight. This anchor is also available in aluminium. I have no personal experiences with these anchors, but would most certainly buy one if I needed another anchor. I used a Fortress-anchor (aluminium) as kedge on my 34 footer and it functioned OK, although not in all conditions.

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[jeanne]

I would agree that there is no such thing as an anchor that is too big, as long as you can handle it on board. I have a CQR of about 35 Kg, which stows itself as you crank it in, so I never have to lift it. I have often blessed it! I had a 50 Lb [23Kg ?] Fisherman, which needed to be handled, and so it was rarely used.
The 'North Grenadines' sounds like Bequia, which is quite deep, and not good holding, unless you are over the coral, when it will hold OK, even when you are trying to lift it. It is also pretty full at times [ Oh! for Christmas at Bequia!], for a big bay. I would take the biggest anchor I could, and try for more than one type, as they all have their strong points.

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[LORDNELSON]

But see latest PBO about a spade anchor dis-assembling itself whilst in use!

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[snowleopard]

i used a 16kg delta on my 40-footer in the grenadines and had no trouble at all(less weight than you but a lot more windage). you will be anchoring in sand and the delta will bury completely after moving about 2 metres. when setting the anchor, allow the weight to come on it gradually, don't try to power-set it as it will just slide over the surface.

the one time you will have trouble with the delta and most other anchors is in hurricane holes like marigot bay where a deep soft ooze covers the bottom. the best thing for these is a fortress on the soft-mud setting.

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[wiggy]

weoght isnt everything, I recently replaced a useless britaney that I could only just lifty with a Fortress that is a one handed ooperation. I know which I would be happiest using when the preverbial hit the fan.

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[wiggy]

Weight isnt everything, I recently replaced a useless britaney that I could only just lift with a Fortress that is a one handed ooperation. I know which I would be happiest using when the preverbial hit the fan.

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[freedom44]

Have you thought of adding a "chum" also known as an angel. This would magnify the holding effect without moving up a size. There is a supplier in Scotland who imports them from New Zealand, approx £100. I have only used mine not in anger so I cannot be too enthusiatic, but Scillies beckons this week so should give a longer opportunity to try it out.

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[stiknstring]

Thanks for all the ideas - I was put off the spade after reading the PBO article (even though the holding power is right up there with the best in all beds). The chum is a really interesting idea, would save me getting a heavier anchor - although in all practicality I will have to get another one anyway - 1 kedge, 1 bower.

Thanks again to all who replied. I appreciate it

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[duncan]

the chum may reduce your swinging circle in certain conditions but it will not increase the ultimate holding of your anchor on full (6:1 is considered full) scope. Only an anchor with a higher holding power (not weight) will do this. If you are unhappy about your main anchor's holding ability then either get a different pattern to complement your existing one (fortress perhaps, spade or SARCA?) or, as you origionally suggested, simply go up a bit on a new delta. btw reducing your swinging circle is fine but only if you are alone or everyone else is anchoring short in some way!

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[hylas]

SPADE dis-assembly

The case of the grounding of Deep Blue is not as simple as it first seems.

A New Zealand Maritime Safety Authority Accident Investigation Report investigated by Jim Lott, NARB, concluded that ¡§the anchor failed when the bolt securing the two parts of the anchor fell out¡¨ and ¡§that this could reasonably be attributed to the failure of the nut that secured it¡¨.
What the investigator seemingly failed to consider is how this could have possibly occurred when the type of nut used is specifically designed not to come loose, and there were no forces acting on it.

Spade anchors are designed to dismantle into two pieces for easy stowage, a very popular feature. The shank is inserted into a socket on the blade and retained by a stainless steel bolt with a ¡§Nyloc¡¨ style nut. During normal operation there is no load on this bolt as the substantial socket assembly takes all the force. At boat shows we often demonstrate this by removing the bolt completely and pulling the anchor as per normal operation. Even when ¡§break out¡¨ is simulated the shank remains inserted in the socket clearly showing that the bolt simply holds the two sections together.

¡§Nyloc¡¨ style nuts are used extensively to prevent accidental loosening of nuts, normally associated with high vibration situations. In the case of the Spade, there is no turning force on the bolt/nut combination and little or no vibration, ¡§Nyloc¡¨ style nuts are used as a precautionary measure to totally eliminate any chance of the nut coming loose. ¡§Nyloc¡¨ style nuts require tools and significant force to tighten or loosen them. If the nut was initially tight, and there were no forces acting on it to loosen it, it could not have come undone. In my opinion, it is extremely unlikely that the investigator¡¦s conclusion is correct.

There are two other possibilities that the investigator apparently fails to consider altogether.

1. The nut was never tightened properly in the first place.

This is a distinct possibility as the anchor was relatively new, was purchased assembled and was not subsequently disassembled. When the Spade anchor was displayed, it is possible that the bolt was only loosely fitted, as purchasers often wish to dismantle the anchor for transport. (¡§Nyloc¡¨ style nuts are designed to be used only once). It is possible that the owner/skipper failed to ensure that the bolt was tight.

2. The nut, bolt and blade were removed after the grounding.

Apparently no attempt was made to recover the anchor until three days after the grounding. During this time somebody could have removed the blade. It should also be noted that the vessel was not insured.

There are a number of other peculiar facts in the case:-

„h The owner was at the top of the mast fixing the tricolour light at 2:30 am when the vessel grounded. The vessel had been at sea for 7 days having encountered rough conditions. They had anchored at 22:30 and then spent two and a half hours providing radio communications for an emergency and helicopter evacuation nearby. It is logical to assume that the crew would be tired. The investigator apparently failed to consider that this could have been a contributing factor.

„h Why was no anchor watch maintained even though all three crew were on deck?

„h Even if the anchor blade had become separated from the shank, the shank and chain alone would have been able to hold the vessel under the weather conditions of the time. *(nearly NO wind, less than 10 knots!)

„h The vessel was apparently anchored too close to the shore and unprotected from the onshore wind. *

„h The Model 80 Spade is designed for vessels displacing up to 4.5T. Deep Blue was estimated to displace 6T.

„h The investigator concluded that the rope/chain combination was sufficient as the ratio was 3.25:1. He failed to take freeboard into account, which would reduce the ratio to approximately 2.88:1. Whilst, according to the report, 3:1 is commonly considered adequate in calm conditions for an all chain rode, this was below that and well below recommendations especially if no anchor watch is to be maintained. For a mixed Chain/rope rode 5/1 or better 7/1 should be used

„h In my opinion, any combination of factors could have lead to Deep Blue dragging including the lack of adequate scope, but the failure to maintain an anchor watch was the primary cause of the grounding.

Despite doubts over the case, Spade have agreed to modify future bolts, as recommended by the investigator, to include a pin after the nut and a note advising that ¡§Nyloc¡¨ style nuts should only be used once. (There is no need to replace the nut after each deployment as reported by PBO, but every time the anchor is dismantled). Existing owners are advised that if they have any concerns about their nuts, that they arrange for the end of the bolt to be drilled and have a pin and new ¡§Nyloc¡¨ style nut fitted. It is the owners¡¦ responsibility to ensure that the nut & bolt (or alternative) are in good condition, secure and suitable for the purpose. It must be emphasised that thousands of Spade Anchors have been sold and that no similar cases have been reported.

Alain d'HYlas


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[eagleswing]

It seems to me that PBO had an article within the past ?5 years on manufacturing your own anchor 'angel' out of some cement or used tyre leads as a weight, and attaching the homemade job to the anchor chain by a shackle. It certainly beats paying all that $$$ for one . the homemade one might be useful to have aboard for heavy weather anchoring as it seems a bit ungainly to be hauling the thing up out of the drink every time one weighs anchor.

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[stuarttoole]

Re: Anchor weights -WI holding

You might want to consider the conditions. Coral sand often gives v poor holding, the coral itself is excellent for getting your anchor stuck, it also destroys warp at an alarming rate. I find a small scuba set very useful. The mooring buoys increasingly being provided to protect the coral are very good indeed. Basically I would agree with the make the second anchor bing heavier and try an alternative design. I would pack a third anchor for the one you might loose.

Regards

Stuart


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