New-ship declarations and protective feed-water tanks

New ships offer more room to manipulate declared ammunition than familiar Queen Elizabeth- or R-class battleships. An allowance of only 100 rounds per gun is imagined for ships designed to take more. Reserve feed-water tanks could occupy otherwise unarmoured spaces, where the water absorbs and spreads some impact energy and the tank adds subdivision. Armour fitted in war could then sit outside that liquid layer. The water could also be drained to reduce draft and increase speed. These are proposed uses of excluded weight, with the protective benefit and operating condition changing together.