Oceanic destroyers gain speed by sacrificing armor but there is no comparable gain in a space-ship. Once the jets are started and the original inertia overcome the heavy ship will travel as fast as the light one because the limiting factor is how much acceleration the crew can stand physically--and it's the same for both. On earth the design of a ship is a compromise between the demands of armament, protection, speed and cruising radius, with the last the least important. For the space-ship speed will make its demands but they will not have to be satisfied at the expense of the other characteristics. However, cruising radius is something else. The ruling consideration in the radius of action of an earth-ship is the ability to carry fuel. Stores for the crew were seldom a problem during the war, even though the food did sometimes run down to Spam and those incredible dehydrated potatoes. Ammunition became a problem in only a few cases. But in the space-navy all this will be changed. Fuel does not look like a particularly serious problem. A given space-ship will be burning lots while she is using it but most of the time she'll be coasting on gained acceleration and will need fuel only for short bursts of maneuver during action. The true limiting factor in the radius of action of a space-warship is the stores for the crew--not food or water but most specifically air. The problem with water is not supplying it but getting rid of it. For every five pounds of food you eat two pounds of water is the minimum result, exuded in various ways. And water is ridiculously easy to purify by distillation. Food itself can be carried in various concentrated forms but it is impossible to carry reserve air except in oxygen bottles under compression and it is very difficult to get rid of surplus unwanted carbon dioxide. For stations in space air-purifiers have been suggested, consisting of algae operating in a churned water-tank. This would be all right for a station which has a steady motion in a determined orbit. But the space-battleship in action will be subject to violent gyrations which would do no good to the air-purifying system even if considerations of weight and space made it practical to install such a system in the first place. Then there is the added danger that a single hit in so vital an installation would put the ship out of action for keeps while a few oxygen bottles blown up would not matter. So the space-battleship will probably have to depend on bottled air, like a pre-snorkel submarine, and the quantity she can carry will determine her radius of action.