Bulges, machinery, and speed in a dreadnought rebuild

What speed could a 26-knot prewar dreadnought retain after 1930s re-engining and torpedo-defense improvements?

The result could range from about 24 to 28 knots depending on power, external versus internal bulges, and whether saved machinery volume is used for protection rather than speed.

External bulges increase protection and stability but worsen the hull's length-to-beam relationship, while internal protection may use machinery space without changing the outer hull. Speed therefore depends on both the new power plant and the chosen torpedo-defense geometry.