An Acacia-class sloop displaced about 1,200 tons and measured 250 feet between perpendiculars, 262 feet overall, with a 33-foot beam and 12-foot draft. Two cylindrical boilers supplied one four-cylinder triple-expansion engine driving a single screw. Figures of 1,400 to 1,800 horsepower were associated with the intended 17-knot speed, but experience suggested that nearer 2,200 indicated horsepower was required. The passage also distinguishes indicated horsepower from shaft horsepower, the power that actually reaches the propeller shaft. Individual ships varied because yards used available machinery and accepted some departure from the class's theoretical standard, allowing rapid production to take precedence over exact uniformity.
Notable Point · 32:29-35:02
Acacia-class dimensions, machinery, and power
At about 1,200 tons and 262 feet overall, the Acacia class used one triple-expansion engine and needed more power than its nominal figures implied to reach 17 knots.