>>831
us navy handbook of damage control

1章を割いて米艦のhull piping system 船体配管システムの説明があるから読んでみたら

https://maritime.org/doc/dc/part7.htm#pg207

とくに29-16. Fuel-oil ballastingのところ

On most ships the fuel-oil tanks must be
ballasted with sea water after the fuel oil has been used.
This is done because of the protection afforded by the liquid layer, and also for
reasons pertaining to draft and stability.