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Old 11-10-2018, 09:14 AM   #12
kchace
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City: Brookline, NH
Vessel Name: Shalloway
Vessel Model: Defever 44, twin Perkins
Join Date: Sep 2013
Posts: 2,260
Quote:
Originally Posted by angus99 View Post
When Velvet Drives do fail, why do some folks opt to replace them with Twin Discs? Cost? Parts availability?

This is anecdotal but I was told the Velvet Drives tend to fail on the starboard side of Defevers (more so than the port trannies in twin configurations). When they do, owners often go back with TDs. When this happens the engine has to be lifted with spacers and a longer shaft (or jackshaft) installed to make up the difference for the shorter gearbox.

Any truth to any of this? If so, I can’t imagine why it would apply mostly to Defevers.
Yes, there is a reason for this, but it's definitely not specific to Defevers. The stb side is the reverse rotation side which has an extra set of gears within the transmission to provide the reverse rotation. All else being equal that side typically needs service first. As far as needing to swap out for a Twin Disk or other, there is no need because the transmissions can easily be rebuilt or a good used one sourced. It's not like they are unreliable or hard to find.

Ken
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