Anchor size for Lewmar CPX4

[Tenedos]

Our new boat (45 ft multihull) is coming with a Lewmar CPX4 windlass and 10mm ISO 4565 chain. But the anchor is useless and needs an immediate upgrade. I have a philosophy of putting the biggest anchor that fits and would like to do the same here. Sizing aside, capacity of the windlass is a concern as we also tend to anchor deep at times (at 100ft/30m when needed).

In an ideal world, I would like put a 99lbs/45kg Spade.

Lewmar CPX4 specs list 1600W, 1250kg max pull and 313kg working load.

According to my math, this should work, e.g. 45 kg anchor + 30 meters x 2.2 kg/meter chain = 111 kg, way lower than the working load.

But a more gut check makes me a little worried, as we have a 1000W Lofrans windlass on our current boat and 55lbs/25kg Spade feel a lot on the windlass when we are bringing it up from 100ft/30mt depth. So I am slightly worried that a 45 kg anchor can be too much for a 1600W windlass when added on top of all chain, when or if anchored deep.

Thoughts?

[Jim Cate]

At around 1/3 of the working load I see nothing to worry about. If you don't trust the windlass mfg for that, how can you trust them for anything?

Seriously, 10 or 15 kg either way for the anchor when you have 60+ kg of chain seems to fall out in the noise.

Jim

[Tin Tin]

We had a cat with 45kg Rocna and 100m of 12mm chain. We were having twist issue so we motored out to deep water let it all out and then expected our quick 1500w Dylan to haul it back up. It would not do it until I gave it a hand for the first 20m after that it pulled it all in OK. So that was a dead drop of 100m. Of course all that metal actually weighs less underwater but 10mm chain I am guessing weighs 20% less - so with just 30m of 10ml out you should be fine. Obviously you need to make sure there is minimal voltage drop so fat cables and/or a dedicated battery next to the windlass.