I thought it was water displacement.
A ship's displacement, or tonnage, is defined as the weight of the water the underwater portion displaces. This weight is equal to the weight of the ship plus the cargo.
The volume of the underwater portion of the hull, in cubic feet, is equal to the gross weight in pounds divided by 64. A cubic foot of seawater weighs 64 pounds.
The volume of the enclosed portion of the hull above the waterline, in cubic feet, times 64 is the reserve displacement.
Hope this helps.
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)
If you like larger numbers for whatever dumb reasons, why don't you convert them to quarts and even pints! Tons suits me just fine, and I can make a better representation of the size of the ship.