Denny-
With all that chain, I'm assuming you'll be using a windlass. Which model and manufacturer will you have? What size chain is it designed for?
5/16" G4 chain weighs 1.09 lb./ft, so the full 275 feet will weigh 300 lbs.!
I seriously wonder if someone has tried to put that much chain in a R-25 Tug?
If you had a windlass designed for 1/4" G4 chain you could save ~100 lbs. of weight.
1/4" G4 chain, weighs 0.74 lb./ft, and 275 feet would weigh 204 lbs.
The differences are:
1/4" G4 = .74 lb./ft, safe working load = 2600 lbs., breaking strength = 7750 lbs.
5/6" G4 = 1.09 lbs./ ft, safe working load = 3900 lbs., breaking strength = 11,600 lbs.
I can't easily find a specification for how many cubic feet of volume there are per 100 feet of G4 chain of various sizes, but if you go to a marine hardware store, find out the measurements of a drum of chain (diameter, length of cylinder), and also how many feet there are in a drum, and you can compute the volume per 100 feet.
Then go measure your locker, calculate the aproximate volume (irregular shape), and go from there!
This will be a fun project!
Joe. :teeth :thup