Designation	Double Ten (D10)
Bore	3/4  inch
Stroke	3/4 inch
Length	5 1/2 inches
Height on box bed	5 1/2 inches
Configuration	Vertical twin cylinder
Extra equipment	Drain cocks Displacement lubricator
Taps required	5, 7, 8 BA 5/32 x 40 tpi 1/4 x 32 tpi 5/16 x 26 tpi
Notes	Popular twin cylinder engine, rather easier to build than the twin launch. Self-starting, with 90 degree cranks, the engine is well suited to use in boats up to 72 inches long and is frequently seen driving a boiler feed pump, steamed from a centre-flue boiler.