How much power would fix the PGM-9?

How much horsepower would the PGM-9 need to reach a useful speed?

A rough estimate puts the high-speed requirement above 16,000 horsepower, while doubling to about 8,000 horsepower and four shafts would be a practical first improvement.

The PGM-9's roughly 2,880 horsepower and 450-ton displacement compare with the 5,000-horsepower Fairmile D and the 8,000-horsepower, 225-ton Steam Gun Boat. Because the American craft displaced almost twice as much as an SGB, simply copying the British installation would not guarantee 35 knots. More than 16,000 horsepower is offered as a rough high-speed requirement, with doubled machinery and shafts suggested as a practical first experiment. Speed depends on displacement, hull form, power, and propulsion arrangement rather than horsepower alone.