Fisher's proposed HMS Incomparable would have carried six 20-inch guns in a very large, fast hull. Armor capable of resisting weapons of that scale would have made the ship unmanageably heavy, so speed and firepower had to substitute for complete protection. Its intended role was to fight enemy battleships, making the design a fast battleship rather than a cruiser built to avoid them. Fisher's broader legacy is a dreadnought lineage in which battleship and battlecruiser characteristics increasingly converged on the heavily armed fast battleship.
Notable Point · 1:37:23-1:40:34
Fisher's legacy in the fast battleship
A discussion of the Incomparable concept traces how Fisher's preference for speed and heavy firepower pointed toward the later fast battleship.