Proper conservative chain length for 39’ catamaran

[smj]

We have a 40’ cat, 6,700lbs, 70 ft 1/4”G4, and 250’ 1/2” line. 45 lb Mantus and no problems.

[Nani Kai]

Originally Posted by Brassmonkeys

The catamaran is 39’ and between 8,800 and 10,000 displacement, 18 beam

I am thinking 150 feet of 7/16 chain and 250’ of a good quality nylon attached to a 45lb anchor.

I am inheriting a 33lb anchor with about 50’ of what I assume is 3/8 chain.

Would love to have a good quality anchor setup for piece of mind at night knowing I already have a decent backup anchor. Do you think this set up is okay?

On our Leopard 39 we have 220' of 5/16" BBB chain attached to a 55# Rocna as our primary anchor with a 44# Delta as a secondary and a 16# Fortress as a 'fast response' anchor. Your idea of 150' of 7/16 chain and 250' of nylon road is fine. Highly recommend upgrading to a heavier primary anchor. You want that anchor to go down, stay down, and hold no matter what the wind and current are doing. Our Delta dragged a time or two which prompted the upgrade to the Rocna. Very glad we did. The Fortress 16# is an amazing anchor. I wouldn't want to sit on it all night in a blow but for getting something on the ground to stop the boat right NOW! it is excellent.

[Tupaia]

Originally Posted by Brassmonkeys

45lb anchor.

a 45lb what?

[Tupaia]

Originally Posted by Tupaia

a 45lb what?

Pressed go too early.
a 45lb what? There is a vast difference between a CQR, Manson, Bruce, Delta, Danforth, Fortress etc, etc.

[meirriba]

We sail 40' Lagoon400 of about 12T (~26,450 lb)
We have 80m (260') of 10mm (~2/5") chain (+unmeasured line rode, maybe 30m).
Replaced original 25kg (55 lb) Delta with 30kg (66 lb) Spade.
Types of bottom we experience is sand, mud, some rocks and seaweed.
Winds up to 45kn.
We are highly satisfied with the setup.Types

[Sailboatuser]

If you are serious about sleeping well at night, then consider 200ft galvanized marine chain attached to the best and heaviest anchor you can afford and your windlass can bring aboard reliably. Use the snubber line with hook to further dampen the pull in strong wind.
Your nylon line is best used not attached to the anchor (can be cut by coral or rock) but to the boat in case your 60ft of chain is not enough. We found 200ft of chain was sufficient everywhere we anchored during 4 years of travel but we also had a nylon rode just in case.

Use 5:1 scope to sleep well or longer if the bottom is not holding very well or you are planning to stay longer or bad weather is coming.
Enjoy your sleep.

[chrisr]

we have a 12m cat with displacement abt 7.5mt, and use a 22kg sarca excel (# 5) on 80m of 8mm G40 chain

never let us down and we sleep soundly at night

cheers,

[MathiasW]

As so many others have said, it depends on where you want to cruise / anchor.

If you have a small range of anchorages that you know fairly well, and if these are rather crowded and shallow-ish water, then a shorter but thicker chain makes a lot of sense, as it will reduce your swinging circle.

If, on the other hand, you are roaming the anchorage places and need to be prepared to anchor in deep water as well, then a thinner but higher-quality (and thus stronger) chain is more advisable. It will do less well in shallow water and it will require a larger swinging circle, but it is more versatile.

Also, as others have pointed out, a good bridle is an essential part of the anchoring gear for a multi hull. In particular in shallow water it can more than compensate for the poor performance of the chain.

More details can be found here: https://trimaran-san.de/die-kettenku...atiker-ankert/

(and a very long discussion in CF here: https://www.cruisersforum.com/forums...pe-235053.html)

Cheers, Mathias