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.