Anchors

[boatboss]

Hi all,

Python is 50' long weighs about 13ton what size and type of anchor do we need. We will mainly be travelling on the tidal and non tidal Trent

How much and what size chain and rope do we require

Boatboss

[Naughty Cal]

Here we go again

 

You will need at least 3 times the chain/rope (your preference) that the maximum depth of water will be (i.e 20ft of water = 60ft of chain/rope) The end nearest the anchor should have a good length of chain to help the anchor set. Some prefer to use just chain. An anchor you can lift is a start. The type of anchor is probably more important than its size.

[carlt]

Same reply as Phylis but I would go further and say, if you can lift it:

 

20kg Danforth anchor with 20' of 3/8" chain and 40' of three strand nylon rope.

 

Happy to be contradicted, though.

[RLWP]

Same reply as Phylis but I would go further and say, if you can lift it:

 

20kg Danforth anchor with 20' of 3/8" chain and 40' of three strand nylon rope.

 

Happy to be contradicted, though.

 

Which reminds me. I must shorten the rope on our anchor as we bought it for cruising the Manchester Ship Canal.

 

Richard

 

Why is this in History and Heritage?

[carlt]

Why is this in History and Heritage?

Because it's an old question that gets discussed over and over again?

[Aunty_Rinum]

.....You will need at least 3 times the chain/rope (your preference) that the maximum depth of water will be (i.e 20ft of water = 60ft of chain/rope).....

If all chain then I would agree that 3 times should be adequate but, if mostly rope, then a minimum of 5 times is necessary for safe holding.

[howardang]

If all chain then I would agree that 3 times should be adequate but, if mostly rope, then a minimum of 5 times is necessary for safe holding.

The figure of three times the depth for the scope for chain is often quoted but this is an absolutely bare minimum and a better scope is nearer 4 to 5 times water depth. You don't have to use it all when anchoring initially, but if the anchor drags you will then have the opportunity of paying out a bit more to stop it. If you have only three times the depth on board and you deploy it you then don't have a second chance to get out of trouble. It's probably worth saying that this is for rivers and relatively sheltered waters. The numbers get bigger in more exposed locations.

 

Howard

Edited July 31, 2009 by howardang