Anchor Locker Questions

Bess and I have a couple of questions about our anchor locker. Firstly is how do you measure it's capacity? And second, how do you determine how much chain and line you can then hold?

I was at the boat the other day and took a few measurements. After a lot of math (ie: solving for the volume of a tetrahedron... and I have to say... not an easy task because I fist had to build the four triangle sides) I can up with a number. Then, I looked at the pictures I took and it REALLY isn't an ideal shape for me to consider the calculations completely accurate. Nevertheless. I *THINK* it is about 1.5 cubic feet. In the picture below... That is only below the lower portion of the opening. However, is there a more accurate way to figure it?

In addition, HopCar is saying that 94 feet of G4 chain fits into a square 5-gallon bucket. Five gallons is approximately .6 cubic feet. But how accurate is that when it is piled in an upside down prism shape (sorta)? Then, you have to account for the line.

The reason for all this is two-fold. Primarily so we can figure how much chain and line we can buy (obviously, the more chain the better), but also, we need to try and keep 16" under the windlass as noted by the owner's manual. We ALSO want to try and split the space to have room for a second emergency anchor.

We are close on all the numbers and want to try and get an accurate measure of the space. I thought about using water, sand, Styrofoam peanuts; all to fill the space and then measure. There has to be a better way, but it seems to be escaping me.

Thanks!

Chain fills a space pretty uniformly when lowered from above. There is a tendency to pyramid when falling into an anchor locker. One of my two roads is 350' of all 3/8" chain. Allowing the windlass to pyramid it resulted in it being taller than the divider. Since it's rare that I will use over 100' (except in a storm), I guided the first 250' of chain to fill the corners, lowering the top of the pile by a third. This made for a solid non shifting mass as opposed to a pile that would fall over. You will find that the rope takes up far more space when dumped in by the windlass, until the chain compacts it down.

How much rope do you want? What size chain and rope?

My solution would be to buy a half keg, load into your locker, and formulate a plan from there.

350' of 3/8" stacks tightly when dumped by the windlass.



Ted

Hey Ted!

We are getting 200' of 5/16 G4 followed by a 100' of line. That will be on our 65# claw. We are hoping someone might know the geometry to figure out the volume of this oddly shaped space. We'd like to partition off the locker into two sections so we can add a second anchor rode that will be mostly line on a fortress.

Seeing your pile of 350' is actually super helpful! . We like your chain markings too.

On my previous boat, the anchor chain capacity was not the problem but keeping the locker door closed with the chain against it was.

Pura Vida said:

On my previous boat, the anchor chain capacity was not the problem but keeping the locker door closed with the chain against it was.

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Was concerned about the same thing when I added more chain. Ended up having a fiberglass board made (Coosa wrapped with bi-axial cloth and polyester) that reduced the opening by 8". The board was mounted on the inside with 4 screws across the opening. It still allows me to reach inside the locker and can easily be removed if necessary.

Ted

Besslb said:

Hey Ted!

We are getting 200' of 5/16 G4 followed by a 100' of line. That will be on our 65# claw. We are hoping someone might know the geometry to figure out the volume of this oddly shaped space. We'd like to partition off the locker into two sections so we can add a second anchor rode that will be mostly line on a fortress.

Seeing your pile of 350' is actually super helpful! . We like your chain markings too.

Click to expand...

Hey Bess,

Think you're going to be hard pressed to equally partition the locker and maintain 16" over the chain pile and rope. If your windlass only handles one road, maybe partition the port or starboard corner to hold the 200' of rope and maybe 30' of chain for the second anchor. In that situation, I would consider only using 25 to 33% of the locker for the second road. Partition could go all the way to the ceiling of the locker and then mount an 8" X 12" deck hatch in the partition in case you need access to the road. How will you store the second anchor?

Ted

Yes, we were thinking 1/3 or less of the locker space for the second rode. Not sure if we will get a second anchor roller or a rail mount for the fortress.

O C Diver said:

I would consider only using 25 to 33% of the locker for the second road

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That is the plan.

O C Diver said:

How will you store the second anchor?

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It is a large FX-37, so there is a bit of a challenge that I am still trying to work out.

Simple test solution would be to cut a piece of 1/4" plywood to mimic the partition and temporarily hold it in place with duck tape. Then load the rope and chain through the windlass. If the partitioned section is too big or could be bigger, cut another piece and repeat the process. Once you have the correct size, I might build out of something other than plywood and duck tape.

Know you will leave adequate drain(s) in the bottom of the partition.

Ted

Can you run a pvc or similar pipe up into the anchor locker from a space below to handle a second rode?


On many boats, it could be a space under the vee berth.

Chain can not simply be dropped into a locker as the chain will pyramid , and the pilev will topple in rough weather .

Then the chain has to be untangled in order to use , a very unsafe condition.

Skeenes Elements has the proper construction of a SAFE chain locker, at your local library, or,,,.

Elements of yacht design : Skene, Norman L. (Norman ...

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Jun 5, 2013 - I recently downloaded the free PDF book, Elements of Yacht Design, by Norman L. Skene, and provided by Cornell University's Library in ...

I'll remember that next time I design and build my own boat. Any idea how to measure the space I already have?

Prior to dumping chain in the locker, I would insulate the elec. terminals attached to your windless.

Tom.B said:

I'll remember that next time I design and build my own boat. Any idea how to measure the space I already have?

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Other than take the basic dimensions, cut them up into calculable spaces, not really...

I will try and help if you post the basic dimensions.

I am sure there other more talented math users than I am here to help also.

Tom:
From your picture in post #1, yours looks more roomy than mine. I have 200' of 5/8" nylon on the bottom. That fills the space to about the original bottom of the door. The chain piles on top of that, and unless I am vigilant about knocking down the rising peak as I haul it in, the peak will stop up the bottom of the ABS pipe that comes down from the windlass within the first 100 ft'. If I knock it over at least every 50', I have no problem getting 210' of 5/16" chain in with room to spare. Not enough room for a second rode.
I don't have any easy solution for a measurement of volume, other than trial and error by loading it up with your rode.

koliver said:

.
I don't have any easy solution for a measurement of volume, other than trial and error by loading it up with your rode.

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Sadly, I guess that is our only option.