A thought occurred to me (
) regarding future warships. If even second rate nations like Iran can field weapons like supersonic anti ship missiles and Skvall supercavitating rocket torpedoes, then sleek "greyhound of the seas" warship designs are pretty much a dead end. Even with exotic hull forms, hydrofoils, lifting bodies and so on, no ship as we understand it will be able to move fast enough to evade an attack by modern weapons. Adding ECM, decoys and weapons like CIWS increases cost and weight (especially up top), things which are critical in a compact warship.
Rather than layering on more and more defenses and electronics, why not build the same capabilities as a Halifax class frigate into a vastly larger hull? If you think of a modern container ship or pure car carrier, there is a giant hull powered by an 11,000KW diesel capable of doing 20+ knots. Cutting down the hull and lowering the freeboard (since we are not carrying 400+ cars) still gives us a ship displacing @ 20,000 tons with considerable room for weapons, helicopters, UAV's, turbine powerplants for dash speed, ASW sonars and hydrophones etc. The key here is most of the hull is still empty space.
Double hull construction with a spacing measured in meters, critical components in widely separated, isolated and shock mounted compartments and maybe even filling the dead spaces with a non flammable foam would provide the ship with the ability to absorb a tremendous amount of battle damage
if and when mines, torpedoes or missiles leak through the defenses. As a bonus, the ship would have much better stability and sea keeping than a compact traditional warship, and probably greater endurance as well.
Operating in littoral waters would be more difficult with a large hull design, but the trade off is the ship can better absorb the punishment that an enemy can deliver compared to a conventional warship. (The tanker wars back in the 1980's are a great example; the USN had an empty supertanker lead the way into the Persian Gulf, and the tanker could hit one or more mines and continue to sail where a warship would be out of action.) The offense is delivered by the high performance weapons the ship carries, the virtue of the ship becomes its seakeeping and endurance, and the ability to fight on even when hit.