This clamp on split half coupling is machined from solid steel and mates with the gearbox output coupling to connect an imperial 1.25" (1-1/4") diameter boat propeller shaft to a Yanmar gearbox, usually via a flexible coupling. The clamp on split type propeller shaft coupling is machined to suit the boat propeller shaft diameter but can accommodate the variations that can occur with normal boat propeller shaft tolerances. It is simple to install and can be adjusted to the required position on the shaft. This clamp on shaft coupling is bored only (no keyway) and is secured to the boat propeller shaft with the clamp bolts supplied. Typical applications include: 4" nominal gearbox flanges of Yanmar KBW10 & KM3 gearboxes. Recommended torque for the clamp bolts: 54Nm (40 lbsft) Coupling dimensions: For propeller shaft diameter 1.25" (bored only, no key way) a - Flange outside diameter = 4.00" b - Hole pitch circle = 78mm c - Number of holes = 4 d - Hole size = 10mm e - Register diameter = 50mm male f - Coupling length = 3.19" g - Coupling clamp boss diameter = 3.38" R & D Marine Clamp on shaft coupling number 202-254D