910-009VO R&D Flexible Shaft Coupling (5" x 13HP Volvo MS4 & MS3)

R&D Marine

910-009VO R&D Flexible Shaft Coupling (5" x 13HP Volvo MS4 & MS3)

Sale price$793.35

Tax included

SKU: 910-009VO
In stock

R & D Marine Flexible Shaft Couplings

The R&D 910 Series couplings consist of a contoured flexible disc moulded in tough yet resilient new type Polyurethane Elastomer.

The contoured disc gives clearance for the bolt heads, is able to flex freely to take up any temporary misalignment of the engine and shaft, due to flexing of the boat structure or the engine moving on its rubber vibration isolation mountings. Forward thrust is taken in compression on the disc between the two half couplings and reverse thrust is taken again in compression on the disc between the two fail straps.
In the unlikely event of a disc failure the steel straps make the coupling fail-safe and ensure drive is maintained in both forward and reverse.


  • Bolts between existing shaft flanges
  • Requires no machining
  • Simple to install
  • Simple to periodically check alignment
  • Reduces engine noise and vibration
  • Fail safe design

Note: All flexible couplings are supplied with nuts and bolts ready for installing.


  1. Engine Horse Power and Engine Speed
  2. Gearbox Type and Reduction Ratio
  3. Gearbox Flange Details, Diameter of Flange. Diameter of Register, Pitch Circle diameter of fixing holes. Size and quantity of holes (pitch circle diameter is the distance between the centre of hole at 12 O’Clock position to the centre of the hole at 6 O’Clock)


  1. Ford Engine 150HP at 2500RPM
  2. Borg Warner Velvet Drive 72C 2:1 Reduction
  3. 5” Flange, 2.500 dia Register, 4.250 PCD, 4 off holes 0.437 diameter

To calculate Power of coupling required:

Horse Power of Engine x Reduction Ratio x 100 = HP/100rpm

      Engine Speed

 150 x 2 x 100 = 12HP/100rpm