I have one on the floor awaiting installation
when the boat gets splashed.
I have been fighting a driveshaft vibration problem since I've had the boat. I had 2.5" overhang with a 1.25" shaft, that has been shortened to 1.25" now that is as short as I can get and still have clearance for the Autoprop. I hope that addresses the vibe issue.
Only thing I would question on Jon's video is the use of red Loctite. I will not use red Loctite myself as it almost always takes a lot of heat to remove, and the Sigma drive is a grease lubricated component and I won't heat it to those levels. I think blue Loctite will be enough and is removable without heat.
Mine is a small Sigma drive an SD 55 I think, but to mount to my 4-JHE it requires an adapter that is an about 1" thick SS plate maybe 5" or so in diameter, this adapter and the Sigma drive add up to a lot of weight.
Also the grade 12.9 studs and the screws on the driveshaft clamp will need to have some kind of corrosion
preventative coating, they are very susceptible to corrosion
The Sigma drive itself is I am sure an Rzeppa CV joint, so it's nothing new at all, just maybe the first time it's used in this application, but an Rzeppa CV joint is enormously strong and lasts nearly forever. If anyone is interested nearly all older Military trucks like the Deuce and a half have Rzeppa joints in the steering
knuckles of the front axle, so they have a very good track record
Maybe it was the adapter that drove the price
up, but mine cost closer to $1,000 than the $500 you paid for yours Jon, you got a great deal