The R&D Marine Flexible Coupling fits between the transmission output flange and shaft coupling. It is designed to protect a boat's drivetrain. The unit will reduce vibration, compensate for some misalignment, isolate the shaft and absorb shock loads. The flexible disc is machined from a resilient and durable polyurethane. It allows the unit to flex, absorbing vibrations and temporary misalignment of the shaft and engine due to movement of the engine or flexing in the vessel's structure. The polyurethane disc is backed up by two metal compression straps, one on either side of the flexible coupling. These metal straps hold the system in constant compression whether the drivetrain is in forward or reverse. This feature extends the life of the system dramatically. The R&D Marine Flexible Coupling will also absorb shockloads resulting from gear changes or the propeller striking a submerged object. The polyurethane disk will distort with light shock loads and is designed to be sacrificial in the event of severe shock load, saving on expensive drivetrain repairs. If the disc is destroyed from massive shockload the metal compression straps keep the coupling intact ensuring that the drive system is functional in both forward and reverse.Reduce engine noise and transmission vibrationReduce costly transmission repairsFail safe design, both forward and reverse thrust is taken in compression from the steel straps, giving a durable design even in extreme conditionsFits most major transmission makes and models. For engines 5 to 1500HPUnder compression load in both forward and reverseQuick and easy installationImpervious to salt water, diesel and lubrication oilsGearbox flange diameter of 101.6mm4 gearbox flange boltsCoupling bolt hole 10mm nominal diameter80mm Bolt PCD60mm diameter Coupling register and 114.3mm maximum diameter couplingMeasure length of 32.5mm10mm Bolt diameterCapacity per 100RPM: 3.73kW 5HPFlexible couplings are as standard non-conducting807737 Earth bonding strip