Chain locker volume

Discussion in 'Boat Design' started by Adarsh Edakkote, Dec 8, 2015.

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Dear Friends,

Can anybody suggest me the formula/Reference to calculate Minimum required chain locker volume?I believe that there is no minimum requirement by classification societies.Please advise

Thanks

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Olavarch. nav.

Yes, there is a minimum volume:

S = 1.1 * d^2 * l * 10^-5 [m^3],

with

d = chain diameter [mm]

and

l = chain length [m].

This volume is for both chains, i.e. the total volume of both chain lockers.

In addition, there has to be a minimum clearance above of 1500 mm and you have to allow for a mud box/sump below.

Hope this helps...

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Dear Olav,

As per below equation,i am getting a minimum volume of 1.04 m3 for 2 chain lockers.

so volume of one locker will be around 0.52 m3.Total length of chain/anchor is 165m and diameter of chain is 24mm.

Available volume is more than 2 m3 for each chain locker.I believe the volume is sufficient.

Please comment on it.Also please provide me the reference rule for this formula.

Thanks,

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steve123Junior Member

Not sure if there are any regulations regarding volume, however CCS rules state collision bulkhead must be located between 5 - 15% of total waterline length from the bow dwl.

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TANSLSenior Member

Olav's formula seems very correct.
I think the position of the collision bulkhead has little to do with the volume of the chains lockers. In my opinion, the collision bulkhead aims rather to create a reserve of buoyancy in the bow and serve as protection against possible impacts. On the other hand, 15% of the waterline length seems too big a distance, though I don't know CCS rules.

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Olavarch. nav.

The formula above is from Germanischer Lloyd (now DNVGL) class rules for seagoing ships (Part 1, Chapter 1, Section 18, Subsection E), but I understand that all IACS members have the same regulations for mooring and anchor equipment.

A common design is to have the chain lockers right in front of the collision bulkhead (so that the bulkhead is also the aft wall of the chain locker), but other than that I can't think of any connection between them.

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TANSLSenior Member

Yes, if you can, the collision bulkhead is used as the aft end of the chain locker, but if that is not possible, an additional piece of bulkhead is placed to close it astern.

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