Length-to-beam ratio, hull form, and capital-ship resistance

At what capital-ship length-to-beam ratio does added hydrodynamic efficiency lose to the resistance of greater surface area?

The balance depends on the hull's cross-section and trim as well as its proportions; no single cutoff ratio is given.

There is no single length-to-beam cutoff in this explanation because the shape of the underwater hull also matters. A flatter hull provides useful internal space, while sharper V-shaped sections offer another way to manage resistance as a ship gets longer. The battleship hull associated with Béarn's conversion provides the illustrated example: a sharp forward section rolls into a fuller form farther aft. Loading is part of the problem too, with a slightly lighter bow proposed to help the ship ride across waves. These choices connect hull proportions to the shape and trim of the complete vessel.