No-foul chain storage locker

[JHuberman]

I have heard there is a formula that uses chain size to calculate the diameter of a pipe to store the chain in so that it flakes in nicely, and pays out without fouling.

I've been searching the net till I'm google-eyed and can't find it.

Does anyone know of this formula, or a table of sizes?

Joseph

P.S.
I did find a site that calculates the volume necessary to store a chain of a particular size and length...

Anchor Chain Storage Calculator

Use the online calulator to get the volume of your chain and then ...

Volume of a pipe = 3.14 x internal radius squared x length

forgot to add....

the longer and thinner the chain locker the better (within reason) so decide the max. height you can conveniently fit below the chainpipe and then use the formula to work out the diameter.

[JHuberman]

I believe the formula I'm looking for tells me the maximum diam locker I can use before the chain will pile up and fall over rather than just flaking neatly into the locker.

[Mike D]

The formula you are referring to is;

V = 0.85*L*D^2 (where * means multiply & D^2 means D*D)
V = volume in cubic feet of the stowed cable
L = chain cable length in fathoms and
D = chain cable dia in inches

or V = 0.1417*L*D^2
using L in feet.

If you prefer metric use
V = L*D^2/49000
V = volume in cubic metres
L = length in metres
D = dia in millimetres.

But be careful of the basic shape etc. of the chain locker.

• If possible it should be circular in plan view. If it must be rectangular make it as square as possible. If it is rectangular with more than 1.5 to 1 proportion of long to short sides the cable may not lie properly.
• There must be no side stiffeners or obstructions to the cable. If this is not possible then angle bar stiffeners should be welded mouth-on i.e. to form a V shape on the bulkhead or use half-round bars. If possible fill up the mouth-on angles with wood and plenty pitch. The same with a pipe-pipe but preferably use a solid half-round.
• If the chain locker is high do not fit a ladder, cut semi-circular holes in the locker bulkhead to form hand and foot holes. Pitch them about about a foot apart horizontally and about 9 or 10 inches max vertically. Remember you'll be very close to the bulkhead and you won't be able to see too well. Grind the edges smooth to prevent injury to your hands.
• The height of the stowed cable (assumed stowing flat or horizontal) should be at least 3 times the diameter of the locker with an allowance of half the diameter to the lip of the chain pipe. If not circular use the diagonal instead of the diameter.
• The chain pipe should be vertical and situated at the middle i.e. at the centre of the circle or at the intesection of the diagonals if not circular. The lower edge of the pipe, the lip, should be flared and very strong and it should be on level with or just below any beams or longitudinals under the deck that is the crown of the chain locker.
• Remember that the cable is only the length stowed in the locker, theoretically you can reduce the actual length by the distance from the anchor shackle to the lip of of the chain pipe. If there are two anchors you'll only stow half the cable. It is obvious but you would not believe how many people have used the entire length on two for one locker.
• You should arrange a drainage space at the base of the locker to allow water to run off.
• Arrange the bitter end to have the attachment outside of the chain locker. If you have to release the cable while at sea you don't want to be inside the locker when the cale flies and takes you with it.

The sizes quoted are the minimum and you should increase them if this does not impinge on your design.

I trust I am not teaching granny how to suck eggs but it might help others who are also wondering.
Michael

Just in case;
Circular
Using the minimum height of stowed cable as 3 times the locker diameter then
pi/4*dia^2 is the area and 3*dia is the stowed flat cable height

and pi/4*dia^2*3*dia = Vol = 2.356*dia^3
so that dia = 0.75*Vol^(1/3) or 0.75 times the cube root of Vol

Rectangular
Say the width of the wide side is W and the width of the narrow side is N. Call the proportion W/N f so f =1 for a square and f = 1.5 for the limit as mentioned above.

The floor area = N*fN = fN^2
The diagonal = (N^2+f^2*N^2)^0.5 = N*(f^2+1)^0.5

Vol = The flat, stowed volume = area*3*diag
Vol = fN^2*3*N*(f^2+1)^0.5 = 3*f*N^3*(f^2+1)^0.5

still with me? Good!

so then N = [Vol/(3*f*(f^2+1)^0.5]^(1/3)
simplify this to N = Vol^(1/3)*a coefficient that depends on on f

Prop'n 1.00 to 1; N = 0.6177, W = 0.6177, diag = 0.8736
Prop'n 1.25 to 1; N = 0.5502, W = 0.6878, diag = 0.8808
Prop'n 1.50 to 1; N = 0.4977, W = 0.7466, diag = 0.8972

So there it is!
If anyone needs more info just ask
M

[Polarity]

...remember that its the weight of the fall of the chain that will overcome the friction required to pull it out of the wild cat (gypsy) and go over the roller.
If the chain storage is too tall and narrow - or the chain piles up, when it gets vertically close to the roller there is not enough weight in the fall and the chain stops going over the roller, right before it jams the windlass.
I have worked on 3 yachts (sail and power) each worth over 5M$ that required someone below to kick the pile of chain over when it got too high! - strangely enough it always paid out Ok but not a safe or pleasant job anyway!

My 0.2 Euros

Paul

[Mike D]

Paul

Good point, thanks. I've never had the problem because even on the smallest vessel we built the chain locker was much lower in proportion than the yachts you describe and the gypsy was always arranged above the chain pipe so there was a vertical fall and the minimum of friction.

Can you keep the Euros for me until there's enough I can exchange at my bank? The bank tellers here think it's a small European car, one thought perhaps it was French - Renault maybe, but another is postive it's Italian 'cos FIAT Euro sounds right!

Michael.

[Polarity]

Fiat Euro - LOL

And you may have noticed the inflation ? that should have been 0.02 Euros!

Where are you Mike?

PAul

[Mike D]

Paul

As you're going to make a trip to the Arctic then wave as you pass I won't see you but the thought would be appreciated.

I live only a few km from where the Arctic explorer J.E. Bernier lived so I live in the Great White North but thank goodness in the southern part. But don’t ask me if I ever bump into your designer Ted Brewer, it’s about the same distance from me to him as it is from you to Baghdad.

You think it's cold in Barcelona! Boyo - are you ever in for a surprise. But the ice is disappearing and it's getting warmer up there, in a few years time it might be warmer than Barcelona.

By the way, I do hope you have permission to venture in our backyard and that your boat is up to the standards laid down in CASPPR http://laws.justice.gc.ca/en/A-12/C....353/17046.html LOL

Aw shucks, you’re off the hook,

APPLICATION
3. (1) Subject to subsection (2) and sections 8 and 19, these Regulations do not apply to a ship of 100 tons, gross tonnage, or less.
(2) Sections 28 to 30 apply to every ship. SOR/78-507, s. 2; SOR/86-451, s. 1.

We all get a break, sometimes and I hope you get a few more to help you on your way.
Michael

[Polarity]

Hi Michael

Thanks for that link there is a lot of usefull info there.

Ok I admit that Barcelona is not much practice for the arctic but... well .. um ...its where I live!( for which read "no valid excuse!")
Re the Canadian Coast Guard and US coastguard - I suspect i will have to present them with a full spec of the expedition, all the safety measures, preperation, equipment, plans for unassisted evacuation etc, etc. Along with my request for permission and a request for suggestions of anything I have missed!
They have turned around and refused entry to at least one unprepared boat I know of - and I dont blame them!
They almost stopped Willy de Roos in 1977 and he writes of their visit which was quite obviously an interview to decide if they were to let him proceed - which they did. - His warm up excercise for the NWP was a singlehanded circumnavigation via Cape Horn - so he knew what he was doing!

Cheers!

Paul

[Mike D]

Paul

Glad you found the link useful. Here’s another one http://www.tc.gc.ca/acts-regulations/menu.htm

It is the Department of Transport of the Federal Government of Canada that administers the laws etc for vehicles, planes, ships etc. So on this site you’ll find most of what you need, our Department of Justice re-writes everything so things can move between this site and the previous one I sent you.

This new site is pretty clear I thing. Scroll down the middle of the screen and the two important links are

• Canada Marine Act – the law on ports, quays etc
• Canada Shipping Act and Regulations – boats and ships. So here you’ll find Tonnage, Freeboard/Load Line and all that stuff.

Another good link http://www.iacs.org.uk/index1.htm This one is the International Association of Classification Societies and all the groups such as ABS, BV, DNV, GL, LR etc are members. The member sites are shown and they give all the offices world-wide.

Good hunting
Michael

[leegrace]

Does anyone have a reference for this chain locker storage calculation? I have it in various places but nowhere that I can reliably reference it from.

Thanks

Lee

[colinstone]

The other tip I heard was to place/fix a traffic cone of a suitable size in the bottom of a chain locker. The chain will then tumble off the cone and fill the corners of a locker. My chain locker is a little wide - http://www.luxe-motor-kei.co.uk/inte...e/image17.html
and it piles up with last few meters of chain. When nicely stowed, the chain only fills about half of the bin. As we only have 2 onboard, we run out of people as one needs one on the winch, 1 driving and 1 stowing!!
I reckon that 2 stainless steel pub beer barrels welded together would be just about right for 13mm chain.

[FAST FRED]

If the chain is big and heavy it is a long slow and stinky job of washing and scrubbing the muck off every single link..

Any bit that gets past will have organisms in the muck, which will die and stink.

So when you design the locker make it easily draining and have access from inside.

Not only to perhaps kick over the pile , but also to hose down the heap of chain , and douche with chlorox or similar.

Old mud stinks like low tide, UGH.

FF

[colinstone]

Even better rig a hose and give it a good blast through the hawse pipe, clearing all the rubbish off before it even reaches the gypsy. My locker has a gate valve on the drain so I can use it a ballast tank.