Blisters

(in Russian, buli), protruding hemispherical objects of thin metal on the sides of heavy cruisers, aircraft carriers, and other large ships, placed at the waterline and below it and extended along two-thirds the length of the ship. In most combat ships blisters serve to defend the basic body of the ship against the explosions of underwater mines or torpedoes. On the inside the blisters are divided by barriers into cells, the outer rows of which are empty, the inner ones being filled with liquid fuel or with special compositions. A significant portion of the energy of an explosion is dispersed in the destruction of the blister and therefore does not reach the main body of the ship. In double-hull submarines the role of the blister is fulfilled by a light hull that is secured to the main solid hull. Blisters contain tanks mainly for water ballast and fuel.