Experience With SigmaDrive Couplers

[holtjp]

One of the projects for this year's commissioning season was to replace the cutlass bearing. Like most boat projects, this soon turned into a much bigger effort involving the cutlass bearing, propeller shaft, and a new coupling. A knowledgeable friend pointed me towards the Brunton SigmaDrive coupling and I was shocked at how reasonable the cost turned out to be. I made the leap and ordered a coupling for a one-inch shaft mated to a Hurth transmission. The U.S. vendor, Roderick Simpson, was fantastic to work with: knowledgeable and patient. Installing the coupling was a snap (I am a five on the 1-10 mechanic scale), but I did run into a big problem with the combination of a new, shorter shaft and the dimensions of the SigmaDrive coupling. This combination, along with my poor calculations as to the placement of the line cutter caused an interference issue. Rod walked me through the problem-solving process and once I removed the line cutter everything was golden. After one-hundred hours of motoring, I could not be happier with the upgrade. The drivetrain is much smoother and the comfort margin for alignment is very reassuring. Rod used some video analysis tools to verify the install and alignment. I would encourage anyone about to do an upgrade of their drivetrain to give the SigmaDrive a look.

My boat: Kaiser Gale Force Cutter. Full keel, heavy displacement cruiser with a Westerbeke 44B engine.