How much anchor chain do I need

[Restoration man]

I’ve got 31 foot twin engine grp boat that will see use on the coast. , boat came with anchor attached to small length of chain that’s attached to rope , I want just chain instead, is there a rule of thumb to how long should it be ?

 

[jrudge]

I’ve got 31 foot twin engine grp boat that will see use on the coast. , boat came with anchor attached to small length of chain that’s attached to rope , I want just chain instead, is there a rule of thumb to how long should it be ?

Where in the world are you ? How deep is the water you typically anchor in.

i have 60m of chain that lets me lunch stop in 20 m of water and overnight in a bit less. It’s the med so lots of chain is not that practical as the anchorage’s are Relatively busy in season

 

[Tranona]

I’ve got 31 foot twin engine grp boat that will see use on the coast. , boat came with anchor attached to small length of chain that’s attached to rope , I want just chain instead, is there a rule of thumb to how long should it be ?

Depends on a number of factors, particularly as already mentioned where you use your boat and what depths you expect to anchor in. Then whether you just want a fair weather anchor or intend anchoring regularly overnight. For most purposes around the UK coast 50m length is OK, which can be a mix of chain and rope or all chain. With all chain for your size boat probably better to nave a windlass as normally you would have 8mm chain and a 10 or 16kg anchor which is hard work handling manually Without a windlass a 20/30m chain/rope is easier. There is a tendency now you go lighter on chain, down to 6mm and use one of the more effective new generation anchors - this is what I have on a heavy 31' sailing boat with a windlass.

 

[QBhoy]

Length of the boat and 3 times the depth, used to be the guide. But all depends on having the right anchor, chain size, conditions, sea bed and common sense…to name a few.

 

[guernseyman]

My 31 foot boat has about 20m of chain spliced to 50m of rope for everyday use. So not too much chain stowed at the bow.
I also carry another 40m of chain which can be connected if strong winds are expected. This is stowed amidships.

 

[Whippersnapper]

Chain double the length of your vessel. My boat is just 9.1m long and has 20m chain and 70m of warp.

 

[Portofino]

As much as you can practically carry for the intended use of the vessel .
As said earlier depends on the depths .

 

[stranded]

Chain double the length of your vessel. My boat is just 9.1m long and has 20m chain and 70m of warp.

I should have thought that vessel length would be among the less meaningful rules of thumb? Likely max depth you will anchor in, nature of seabed, ability of boat to carry weight of chain, how the rode will be handled including, if you go for smaller high strength chain eg G70 whether it would even be possible to splice equally strong rope to it, are all more relevant.

 

[Boathook]

I’ve got 31 foot twin engine grp boat that will see use on the coast. , boat came with anchor attached to small length of chain that’s attached to rope , I want just chain instead, is there a rule of thumb to how long should it be ?

As per others where do you use the boat and depth of water you are likely to anchor in. As a rule of thumb for all chain use 3 times the depth. If the wind picks up you may require 5 times the depth. As far as I'm concerned the depth is from the bow roller to sea bed.
What size windlass do you have? if none I would look at 6mm G70 chain. If you search for Neeves on PBO and scuttlebutt there are lots of posts about anchoring and the rodes used plus the snubbers to make it more comfortable at anchor. The smaller chain makes get shackles a bit more difficult but it is mainly a case of ordering from a company such as TECNI Ltd.

 

[Farmer Piles]

I have just bought a boat, 32ft, that had been on Lough Erne and then the Severn so she only had 30 of 8mm chain. Having looked at the options I went for all new chain, the pricing was such that 60m was only a fraction more than 50. So I now have 60m. I just figure that when overnighting I will be able to rest more easily. She is a semi D hull so rides a bit nose up, a bit of extra weight in the bow is no bad thing - but it's only an additional 40kg or so.
Also, being of the belt and braces nature, I thought that I could use some of the old chain plus some warp for a second anchor. There are several 15kg CQR types around locally at sub £50.

 

[Restoration man]

Thanks for the reply’s The boat will be used on the river seven and the Bristol Channel, I’ve not boated in this part of the country for 20 years , so can’t remember how much anchor chain we used , hence me asking , I’m removing the winch tomorrow so I will check what size chain it takes

 

[Farmer Piles]

I would suggest that with the huge tidal range of the Bristol Channel that the tidal flow and currents will be very strong so err on the side of overdoing chain length and size. Within sensible limits obviously.