A bobbin coupling is a double flange coupling, which is used to extend the boat propeller shaft. They can also be used for making a double flexible coupling with two R&D type flexible couplings. This can provide excellent noise and vibration control, at a very reasonable price.

The 6" R&D bobbin coupling is machine from steel, and the flanges will suit gearbox flanges (5.75") for PRM, Borgwarner Velvet Drive, ZF and Twin Disc gearbox.

Bobbin coupling dimensions:

a - Flange outside diameter = 5.75"

b - Hole pitch circle = 4.75"

c - Number of holes = 6

d - Hole size = 0.50"

e - Register diameter = 3.00" male on one flange and female on the other

f - Bobbin coupling length = 5.86"

g - Bobbin neck diameter = 4.25"

R & D Marine Bobbin shaft coupling spacer number 202-250