What is boiler horsepower ?

Answer 1

unit of power, 19th-20th centuries, defined by the Boiler Code Test Committee of the American Society of Mechanical Engineers, and used in rating a boiler’s capacity to deliver steam to a steam engine. One boiler horsepower is about 33,478.8 Btu per hour (about 9,809.5 watts).

Boilers in ships were not customarily rated in boiler horsepower