anchor windlass question

[prv]

Mentioned above is Bradney Chain...... Go to them by far the best information and less expensive than the swindlers.

Seconded. That's where I got mine from.

They can also weld on an oversized link at each end of your chosen length of chain. This is so that you can fit an anchor shackle as strong as the chain - without it you might only be able to get an 8mm shackle pin through the end link and for some reason these are much weaker than 8mm chain. Bradney's can also sell you the appropriate shackle, including one with a low-profile pin end if you need it to fit through a narrow bow roller (though in my case the roller was so stupidly narrow that even that didn't work, and I had to get a special high-tensile shackle from a lifting supplier to maintain the required strength).

Incidentally, the reason you put the big link on both ends is so that after many years, when the working end of the chain starts to get worn, you can swap it end-for-end.

Pete

 

[Storyline]

Certainly it would be hard to argue against that!

However, if you only have a finite amount of weight to play with (and I do, otherwise my boat will float bow-down and perhaps start to hobby-horse in short seas) I think it's better used in the anchor than in the chain (provided of course that you put enough into the chain for sufficient strength).

With enough wind, the chain will be pulled into a nearly-straight line from anchor to bow. I don't think I've been anchored in bad enough conditions yet to have experienced that first-hand, but I've read several accounts of it and seen calculations that back it up. Is this the part that you disagree with?

If we accept the above, then what exactly is the weight of the chain doing for you? It can't absorb shocks or anything like that, because it's already a near-straight line, there's nowhere for it to go.

The chain's job here is to keep me connected to my nice big anchor (all the bigger because I had the "spare" weight to use on it) - it's strength I need from the chain, not weight.

Pete

I can see your point but from my experience if one was to upgrade one of the components I would go for an increase in chain size.

Several years ago we spent a summer cruising in company on the west coast of Scotland with another boat of very similar size to ours. We both had 35lb CQRs but our friends had 5/16" chain and we had 3/8". A series of gales caused our friends to drag several times whilst we always held. The holding was same and it happened too many times to be just coincidence.

Also, for us (sailing on the west coast of Scotland) there are several secure anchorages where there simply is not enough room to set all your scope.

 

[noelex]

50m of 10mm chain weighs over 37kg more than the same length in 8mm. (The difference will of course be greater for the 80m contemplated)

So for the same weight do you want a 15kg anchor with 10mm chain, or a 52Kg anchor and 8mm chain. Which would you pick in blow?

52kg would be a massive overkill, but the maths shows the principal of putting the most weight in the anchor rather than the rode.
A slightly more modest anchor would enable more 8mm chain to carried ensuring in a long scope can always be used when necessary. It also opens up the ability to anchor in alternative, deeper, anchorages which may be more suitable, or away from other boats that may drag.

 

[prv]

I guess there's one other point to consider in chain-vs-anchor weight distribution - where do you keep your chain? If it's in a deck locker right up in the point of the bows, then its weight is directly interchangeable with weight of anchor as we've been discussing (assuming you keep your anchor on a bow roller in the modern style). However, if you pipe your chain to a locker further aft, a kilo of chain has less effect on trim than a kilo of anchor, which may affect the decision. My fantasy world-cruiser design has the chain just a few feet forward of the mast, in a vertical locker built against the watertight bulkhead between cabin and forepeak. That boat, in the highly unlikely event of it ever being built, would have plenty of weight of chain!

Pete

 

[noelex]

That boat, in the highly unlikely event of it ever being built, would have plenty of weight of chain!

Pete

It is a good idea and is used on some boats, even production boats, like the Boreal.

It does have the drawback of possibly dirty and muddy chain across the deck and the difficulty of draining the locker if its central.

A chain locker further back, but still in the bow area, with an outside locker for fenders etc forward of the chain locker would probably be my ideal.

 

[prv]

It does have the drawback of possibly dirty and muddy chain across the deck and the difficulty of draining the locker if its central.

This is true. I was planning to have the locker sealed from the interior of the boat, with a UHMWPE (plastic) grate near the bottom of it and a sump for water under that, connected to a small manual diaphragm pump in the focsle. I could give the pump a few strokes from time to time as I went past, to keep the water level down. There would be an access hatch in the side of the locker, so when the sump eventually filled up with rust flakes, mud, grit, etc the chain could all be laid out and the bottom of the locker overhauled. It's basically all modelled on a smaller version of Stavros's chain locker.

The foredeck arrangement on this design carries the side deck "planking" (I originally wanted traditional thick wooden planking over the metal deck, but we all know that's not sensible) up each side of the foredeck but leaves a slightly sunken channel across the middle of it, which would take the chain (it also provides a foothold on a heeling deck without sliding down to the lee bulwark).

A chain locker further back, but still in the bow area, with an outside locker for fenders etc forward of the chain locker would probably be my ideal.

That makes a great deal of sense for a boat with the standard modern layout. But my design has a traditional focsle instead of a forepeak cabin - lots of stowage, small workbench, traditional raised forehatch and ladder to get in, etc. I want to carry that right up to the stemhead. Actually I did consider a sealed deck locker in the bow, as a garbage locker, but decided that kind of dedicated stowage would be inflexible. The real-world solution would probably be knotted compactor-sacks lashed down in the deck-cargo area between deckhouse and mast.

Pete