Here is the reason for the gearbox failures associated with freewheeling. It
has nothing to do with the Velvet Drive specifically. It has everything to
do with hydraulic gears that operate on hydraulic oil pressure derived by
the engine only. In that light, lubrication is also provided by the engine.
Gear failures under freewheeling conditions are usually output thrust
bearing failures due to the lack of of lubrication and high bearing load. If
prop shaft thrust is low, shaft speed is slow and some lube is provided by
splash by the reduction gear, no damage will occur. Any deviation from the
above induces risk. You could alsodrive an auxillary pump off the shaft,
drawing oil from the gear sump and feeding an inlet port will also buy the
insurance you desire.
Steve
"beaufortnc" wrote in message
ups.com...
Hi,

In previous threads, I've read that, even though the manual for the
velvet drive (w/ a perkins 4-108) can be freewheeled while sailing,
real experience proves this to be harmful and even catastrophic to the
tranny.

Some suggest that if the motor is started periodically (6-8 hours) then
the tranny will be ok.

Should we just plan on starting the motor every 6 hours and motor
sailing for twenty minutes before shutting the motor down?

or

Should we bite the bullet and buy a Maxprop?

---

Hey Glenn - while you're making a prop, maybe you could whip up one for
me too!

Thanks,

Mike.