Volume needed for chain

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BabaYaga

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Hi all,

I’m thinking about modifying the anchor locker of my boat this winter, by creating a self-draining ”pit” that should be able to hold 15 – 20 meters of 8mm chain (part of a chain/rope rode).
However, I cannot find any information on the volume needed to accomodate a certain length of chain.
One meter of 8mm chain seems to weigh about 1,42 kilos, but how much space would it occupy?

If anyone knows or could give me a hint, I’d be most grateful.
 
OK, so how about putting a length (say 10m) in a bucket and mark how far up the bucket it fills. Empty out chain and fill bucket with water to mark. Make a note of how much fluid is used and you have the volume.

73s de
Johnth
 
Sorry, should have made clear that I don't actually have the mentioned anchor rode yet – or any length of 8mm chain.
If I did, it would have been easy enough, using a bucket as suggested.
 
There's an old imperial formula for the size of a self draining locker:
Cu.Ft = fathoms x diam. in inches x 0.85. A fathom is 6 feet, 8mm is 0.32". So, 20m of 8mm chain would occupy 0.85 cu. meters - if my maths is right!
 
0.85 cubic metres is about the size of a large office desk so that can't be right. I keep 20 m of 7mm chain and 30 mm of 12mm anchorplait in a space with a volume about the same as a 5l fuel can, possibly a bit more but certainly nothing like my Salty friend's suggestion. He's usually pretty reliable too.
 
:rolleyes:
KenMcCulloch said:
0.85 cubic metres is about the size of a large office desk so that can't be right. I keep 20 m of 7mm chain and 30 mm of 12mm anchorplait in a space with a volume about the same as a 5l fuel can, possibly a bit more but certainly nothing like my Salty friend's suggestion. He's usually pretty reliable too.
Click to expand...

I think you'll find that's the volume of the drawers, not the entire volume taken up by the desk . :rolleyes:
 
KenMcCulloch said:
0.85 cubic metres is about the size of a large office desk so that can't be right. I keep 20 m of 7mm chain and 30 mm of 12mm anchorplait in a space with a volume about the same as a 5l fuel can, possibly a bit more but certainly nothing like my Salty friend's suggestion. He's usually pretty reliable too.
Click to expand...

Agree. Using the formula I get the result 0.084 cubic meters – or 84 litres. Seems more realistic, but still a lot compared to fuel can volume. Was that really just 5 litres? Or 15?
 
Just been out to the garage where I have 38 metres of 8mm chain in a plastic box with the following dimensions: 40cm x 32cm, the height is irregular but just under 20cm at the highest.
Gives a volume of just over 25 litres.
 
Recently had 45m x 8mm chain delivered in a 25l drum. There was ample space at the top and I would guess the occupied volume to be 20l.
On this basis your 15 - 20 m should take up between 7 and 10l.
 
Thanks all for your comments so far. I think I'll stick with the 'real life' estimates, although they don't quite line up.
From what I've learned, I would be on the safe side with a volume of some 12 litres (less than half a cubic foot?) för the 20 meters of chain.
 
My apologies, a decimal point error! 0.08cu m. is what I meant. I was only out by a factor of ten - no-one's perfect!

The formula is, as I said, for a complete anchor locker to hold a certain amount of chain. If you want to stow chain and rope then the rope portion takes up 25% more volume.

In the OP's case a densly packed sump seems to be required, but I hoped the formula might provide some assistance.
 
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