10mm or 8mm chain? And how much?

[Colvic Watson]

The boat is a 34ft Colvic Watson displacing about 14 tonnes. The electric windlass has died so we need a new one & the chain has rusted beyond my confidence in it, so we need both. In an ideal world I'd buy 50m of 10mm chain but that is very expensive and a big heavy lump in the bow. So I thought 30m of 8mm would be fine as we have lots of anchor warp to add. Having looked at the Jimmy Green site that is within their recommended tolerances but what do you think? A big part of this decision is the way it affects the choice of a new electric windlass - many of the less expensive ones are only available up to 8mm.

Almost all our sailing is coastal and on the East Coast though next summer we will be spending six weeks in the west country.

Thanks.

 

[Sans Bateau]

On our 35 ft boat (only 6 tons) we carry 25 metres of 10mm chain, then multiplait warp. Evans Starzenger (?) in one of his articles on anchoring suggests its better to have all the chain of a heaver gauge on the seabed, than a lighter chain in the locker.

PS our set up is what came with the boat.

 

[sighmoon]

We have a 38 foot boat, it's still only 6 tonnes but over 13' wide so a lot of windage. We have 45 metres of 8mm chain. Surveyor suggested that when I replace it, 50m chain is a minimum. A couple of times this year (once in Cornwall), we did put the whole lot out; we may not really have needed it, but it wasn't doing any good in the locker, and I slept better knowing we had 5:1 scope at high tide. We also have 40m of warp, but we only used a few metres of it as a snubber. If there are any rocks around, you need to make sure warp is off the seabed.

Given an equal weight of chain, I think I'd prefer the longer, thinner stuff - you can anchor in deeper water, you can get better holding by putting out more scope. If your new windlass packs up, you can lift 8mm of the seabed by hand easier than 10mm.

 

[Mudisox]

Two of the questions you have to ask is in what depth of water do you
a. normally anchor in and
b.are likely to anchor in.
I would suggest that it is rare that you anchor in anything greater than 10m, occassionally 25m so 50m of 8mm chain backed up with 10mm octoplait does the job nicely. That puts 50m of chain on the bottom and 10m of nylon up to you giving a 3:1 in calm conditions and if it is windier, then let out more rope and the chain should still be able to take the wear on the bottom and the rope will act as a spring.
In buying a windlass, remember to have a drum as well, as you'll find all sorts of uses for it- like helping someone haul you up the mast!

 

[Bosun Higgs]

The boat is a 34ft Colvic Watson displacing about 14 tonnes. .

So thats where all the depleted uranium went!

 

[sarabande]

on my twin boat, I had 60m of 10mm galvanised for the main bower anchor, plus another 60m of 10mm for the fisherman. I wouldn't go down to 8mm - especially in the West Country.

 

[prv]

30m seems a little short to me. I inherited 40m of 8mm on our 24-footer and have no desire to reduce it.

Pete

 

[vyv_cox]

The chain sold by Jimmy Green is Grade 40, as such stronger than the average chandlery Grade 30 by a good margin. This is a good way to save weight while maintaining the strength of a larger size.

IMO 30 metres is not enough, with this length you will be relying on rope on many occasions. Nothing wrong with its strength but it can be a nuisance to stow in the chain locker, may not be very compatible with the windlass and is more subject to wear and chafe. In UK I always had 50 metres of chain, in the Med 60 is just enough.

 

[NormanS]

If your displacement is 14 tons, the extra weight of the 10mm chain is not going to make much difference, except to your pocket.

If you go for a shorter length, or a lighter chain, there will come a dark night when you'll lie awake wishing.......

 

[duncan99210]

Our boat is 12 metres long, 3.8 wide but only weighs about 8 tonnes. We carry 70 metres of 8mm chain here in the Med and have occassionally had most of it out on the bottom. For what it's worth, I think the tensilethe strength of 8mm chain is more than enough for your boat and longer the chain the better as far as holding is concerned.

 

[bikedaft]

have same dilemma - 6 ton hustler 35. 75m of 8mm chain. getting rusty.

from jimmy green's website, 60m of 8mm weighs 86kg, 60m of 10mm weighs 136kg so difference of 50kg (tho i would possibly go for 90m with a difference in weight of 75kg)

so reckon a difference of 60kg in a boat that displaces 14tonnes would make little difference

my main reason for going for heavier size is that have sailed on a 3 tonne boat for 30 years, and rarely dragged anchor with 8mm chain, so 8mm seems a bit undersized on a boat that weighs twice as much, never mind your uranium 14tonner

 

[Caer Urfa]

The boat is a 34ft Colvic Watson displacing about 14 tonnes. Thanks.

Hi Simon

Your boat is a Colvic Watson Veracity class, and should weigh 13 tons, the recommended design criteria says the anchor should be a 45 Lbs CQR Type, with 3/8" chain suitable for a depth of 50 fathoms (300').

Regards
Mike

 

[NormanS]

Hi Simon

Your boat is a Colvic Watson Veracity class, and should weigh 13 tons, the recommended design criteria says the anchor should be a 45 Lbs CQR Type, with 3/8" chain suitable for a depth of 50 fathoms (91.5' approx)

Regards
Mike

91.5 whats? 50 fathoms is 300 feet. WOW!

 

[Colvic Watson]

We've got a 60lb genuine CQR anchor and that chain quote suggests just 30m of 10mm.

BTW, a replacement genuine CQR would be over £1000 - shame to loose it

 

[Colvic Watson]

91.5 whats? 50 fathoms is 300 feet. WOW!

I'm confused

 

[PuffTheMagicDragon]

I'm confused

300 feet = 91.44 metres?

 

[Colvic Watson]

I'll stick with 50m max. We are a heavy boat - but 100m of 10mm chain right at the bow? Holy mackerel