Flexible coupling for boat propeller shaft.

Manufactured by R&D Marine, this flexible coupling fits between the boat sterndrive and the engine flywheel. They were also be used on some early boat propeller shaft coupling. This flexible coupling consists of a contoured flexible disc moulded in tough yet resilient new type Polyester Elastomer. The contoured coupling disc gives clearance for bolt heads, and allows the coupling to flex freely to take up any temporary misalignment of the engine and sterndrive, due to flexing of the boat structure or the engine moving on its rubber engine mountings. A safety feature of the R&D 910 series flexible couplings is that in the unlikely event of a coupling disc failure, the steel straps make the coupling fail safe and ensure propeller shaft drive is maintained in both forward and reverse.

Sterndrive / Gearbox Flange Dimensions

- Diameter: 101.6mm (4.00")

- Number of gearbox flange bolts: 2

- Coupling bolt hole nominal diameter: 11.2mm (0.44")

- Bolt PCD: 76mm (3.00")

- Coupling register diameter: none n/a

Flexible Coupling Details

- Coupling maximum diameter: 108mm (4.25")

- Length: 41.7mm (1.64")

- Bolt diameter: 7/16" UNF

- Capacity per 100 rpm: 1.87kW 2.5HP

- Typical applications: Sonic Sterndrives, Enfield Stern Drives and replacement for Metalastic 21/868 coupling

- Electrical properties: Flexible couplings are as standard non-conducting

- Earth bonding strip: 807736