Why the Nelson class was not a fast battleship

Were the Nelson-class ships fast battleships?

No: they were not fast battleships as built, though additional boilers might hypothetically have raised them to about 28-29 knots.

The Nelson class was not a fast battleship as built. Reserving space for additional boilers, or fitting them in the late 1930s, might have raised turbine output enough for roughly 28-29 knots. That speed belongs to a hypothetical modernization rather than the class's historical performance. The Nelsons are contrasted with the King George V class, HMS Vanguard, and the Iowa class, which are routinely described as fast battleships. Actual classification should remain separate from an unrealized engineering possibility.