How much does a metre of 10mm galvanised chain weigh in water?

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Oscarpop

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Just trying to work out if I would be able to hold off having an electric windlass installed on the new boat. I installed the last one with few problems, and the £4,000 price tag seems a little much.So will install it later.

I figure that I will rarely anchor in more than 10 metres of water. This means that I will have to have the strength to lift 10 m of 10mm galvanised chain straight up through water will a 16kg anchor at the end.

Can any of you give me the equivalent weight that this will be.

Oh, and I do realise that the weight is the same, but the buoyancy makes it feel less.
 
Since the specific gravity of iron is ~8, the chain & anchor will "weigh" about 7/8 ths. or 88% of its dry weight, eg, your 16 kg anchor will weigh 14 kg. likewise the chain.
Edit:- For the pedants, just checked SG. it's a bit <8, so buoyancy effect will be slightly greater than above, ie lighter.
 
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cast iron varies 7 to 7.4 g/cm³ call it 7.2 so 16kg anchor will effectively weigh about 13.8kg in water

10mm chain is 2.25 kg/m so 10 m in air will weigh 22.5 kg but density of steel is 7.8g/ cm³ so effective weight in water will be approx 19.6kg

In water combined weight of anchor and chain will therefore be 33.4 kg. or in old money a bit over 73 lbs

Windlass definitely required IMO
 
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Remember that unless there is absolutely no wind or tide, the chain is unlikely to be vertical. You may also have to break out the anchor, (unless it's one of the types that people here say don't work):D
 
simonfraser said:
the mass of the chain will be the same, it will 'weigh' less in water . . .
Click to expand...

Thank you for drawing that distinction between mass and weight.

Since the units of weight are Newtons my earlier post should of course have read:

cast iron varies 7 to 7.4 g/cm³ call it 7.2 so a 16kg anchor, which in air weighs 157 Newtons, will effectively weigh about 135 Newtons in water

10mm chain is 2.25 kg/m so 10 m will be 22.5 kg and will weigh 221 Newtons but the density of steel is 7.8g/ cm³ so the effective weight in water will be approx 193 Newtons

In water combined weight of anchor and chain will therefore be 328 Newtons. In old money a bit over 73 lbs f.

Windlass definitely required IMO​
 
NormanS said:
Remember that unless there is absolutely no wind or tide, the chain is unlikely to be vertical. You may also have to break out the anchor, (unless it's one of the types that people here say don't work):D
Click to expand...

In my experience the breaking out of the anchor is the bit when, if anything, you'd need a winch. If you can manage that bit then hauling up anchor and chain is easy. It's not easy to quantify but I'd guess that breaking out from sticky mud needs at least 3 times the tension as does lifting anchor and chain so buoyancy effects can be ignored. Of course in terms of work required as opposed to chain tension required the breaking out only requires you to move a meter or so of chain compared with the 30 meters of full lifting.
 
The instructions for my windlass includes things that it should not be used for :-
1 mooring (use cleats, bits, sampson post, etc)
2 pulling a boat up to the anchor (use the engine)
3 breaking out the anchor (use the engine)

The manufacturer warns of possible damage to the motor or gearbox or both as any of the above can exert loads higher than those designed for ( ie just lifting chain and anchor).

PS Sorry for the thread drift.
 
Oscarpop said:
Just trying to work out if I would be able to hold off having an electric windlass installed on the new boat. I installed the last one with few problems, and the £4,000 price tag seems a little much.So will install it later.

I figure that I will rarely anchor in more than 10 metres of water. This means that I will have to have the strength to lift 10 m of 10mm galvanised chain straight up through water will a 16kg anchor at the end.

Can any of you give me the equivalent weight that this will be.

Oh, and I do realise that the weight is the same, but the buoyancy makes it feel less.
Click to expand...

Just fit it!

For your intended use, you will regret it if you don't and it will cost you even more when you have to.

Mind you, just like everything on the boat you are buying, it is way overpriced. Exactly the same thing on an AWB would be half the price - or even less! The Lofrans Cayman on my Bav was under £1k (I know 10 years ago, but prices have not changed much). And get controls for the helm, or at least a remote control. It will be the best thing on the boat when you get to the Med and have to start anchoring in steeply shelving bays, or backing up to a quay using your own anchor.
 
>I figure that I will rarely anchor in more than 10 metres of water. This means that I will have to have the strength to lift 10 m of 10mm galvanised chain straight up through water will a 16kg anchor at the end.

In ten metres depth you will need five time depth, 3 metres is ten times, 20 metres is three times. It's all about the weight of the catenary as the boat moves back and swings.

By the way 4,000 is a rip off. Buy the winch yourself and negotiate a discount. Then find somebody who fits winches and the associated wiring. To stop current drop the battery should be close the the winch control box, in a box under the forepeak berth. That saves on the wire cost too.
 
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I guess the chain will feel heavier in fresh water than in salt - you didn't specify.

But £4000 for a windlass? Too much
I bought a Lewmar Pro windlass and installed it myself - no big deal very easy and all parts come with the kit.

But in 10m depths, you will have sore arms pulling in those 40-50m chain and anchor.
 
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