Anchor chain upgrade and windlass maintenance

Imagine riding out a gale in some remote anchorage only to suddenly lose one’s anchor hold. Knowing Murphy, it would happen in the middle of the night and the wind would capriciously shift to onshore the instant you drifted. In my book that's high on the list of things that can go horribly wrong at sea. Fortunately, unlike hitting an uncharted rock, this scenario is 100% avoidable. You just have to have the right ground tackle and the right technique - and choose the right anchorage.

Arriba’s anchor is less than 4 years old and in very good shape, with zero evidence of loss of galvanization. The same, however, cannot be said for the anchor chain, which is 10 years old. The chain is badly corroded in many places (below).

Re-galvanizing might have been an option had I caught the rust earlier, but frankly for something as critical as anchoring, I prefer to have new chain. Besides, 10 years is not a bad innings.

After removing the old chain there was about ½ kg (~1 lb) of rust accumulated at the bottom of the chain locker. Yikes! In future I'm going to make it a point to rinse the chain in fresh water more regularly to minimize rust from developing.

Arriba has a generously sized chain locker, so I decided to replace the 50m of old chain with 70m of new grade “L” chain. That extra 20m means another 4 meters of anchoring depth at 5:1 scope.

L grade chain, properly stamped.

Researching anchor chain, one could be excused for thinking that steel strength is all that matters, but it's not that simple. The quality of the steel and the weld is definitely a factor, but in all likelihood a chain will fail because it has rusted, not because the steel was inferior. So the quality of the galvanization is just as important as the quality of the steel. For anchor chain, a galvanizing coating that is at least 60 microns (0.06 mm) thick and evenly applied is considered reasonable. Too thin, and it wears too quickly. Too thick, especially if it is uneven, and it can flake off.

BTW, I found a great way to load new chain and prevent it from scraping the deck is to feed it through a PVC tube (shown below). One person is all you need too.

The other critical piece of anchoring equipment is the anchor windlass, without which weighing anchor is difficult, if not impossible. Arriba’s windlass started developing two problems; sometimes it would slip and other times it would jam. With the help of my local marine store, the cause of the slippage was identified as excessive grease on the clutch. The manual refers to regularly greasing “all moving parts”, but in fact almost no grease is required. If the shaft is greased too much, the excess can ooze onto the clutch surfaces causing the clutch to slip. That explained the first problem.

The second problem, jamming, was even more serious, as it could happen just when least expected. Arguably the most vital component of any windlass is the “chain wheel”, a drive wheel with special indentations or “pockets” to suit a specific chain type. It is critical that the chain wheel match the chain size exactly as even a small difference in size can cause excessive wear on the chainwheel and/or hinder smooth movement of the chain. In Arriba’s case, the poor condition of the chain meant that the chain links were no longer nesting properly in the chain wheel pockets, causing the chain to fall off the chain wheel and jam.

BTW, in Australia and the UK the chain wheel is called a “gypsy” and in the US a "wildcat". 

Here are photos of the windlass before I cleaned it:

Here it is cleaned and polished - (almost) as good as new - with just the tiniest amount of grease on the spindle.

Finally, I came across these neat "chain rainbows" which snap between chain links and seem like a great way to mark chain lengths. They come in a variety of colors but I used just blue and red. I inserted a blue one per 10m of chain, i.e., 1 for 10 m, 2 for 20m, 3 for 30m, etc. I used red ones to delineate the ends, i.e., at 5m and 65m. Time will tell if they stay in place.

I’m happy to report that Arriba’s ground tackle is now in tip-top condition.

OVER.