Why more T1 machinery bought little speed

The early T1 boats delivered about 28,000 shaft horsepower against an intended 31,000, yet achieved 35 knots against a 34.5-knot design speed. Later boats reached about 34,000 shaft horsepower and 36.6 knots. Roughly 6,000 extra shaft horsepower therefore bought only 1.6 knots. Higher speed requires disproportionate power, but the explanation also concerns hull form and where weight was placed. A hull that kept digging into the water at speed generated more friction, while the water flowing past its rudder helped preserve control at lower speeds. Later bow designs helped improve that balance between fast running and maneuverability.