Can you freewheel a Velvet Drive while sailing?

What the factory says

This comes up constantly with sailboat owners running a diesel auxiliary. You're under sail, the propeller is turning whether you like it or not, and it's natural to wonder whether that's doing any harm to the transmission bolted behind the engine. Velvet Drive answered the question directly. The 71C/72C and V-drive owner's manual states that these transmissions "can be freewheeled without risking damage in sailing or trolling applications." The Liberty owner's manual says the same thing, covering sailing or trolling on a single engine of a twin.

Velvet Drive's 1982 installation manual gives the reasoning behind it: the design "maintains adequate cooling and lubrication" while the propeller keeps the internals turning under sail.

Neutral or in gear

None of the three manuals we have on file state a required lever position for freewheeling, which is a strong hint they mean neutral. That's what we'd do: put the lever in neutral before you raise sail or settle into a troll, rather than leaving it engaged in gear. The one condition every manual repeats is oil level. Check the dipstick with the transmission warm and in neutral, and read it right away since fluid drains back out of the cooler once the engine stops. Don't head out for a day of sailing on a level you haven't actually checked.

If you want the shaft stopped

Freewheeling and locking the shaft are two different things. If what you actually want is a prop that isn't turning at all, rather than one spinning freely under sail, sailors who write about this on rigging forums generally agree the gearbox itself isn't a reliable way to do that. That takes a shaft brake, or a folding or feathering prop. That's sailors sharing their own experience, not a line out of a Velvet Drive manual, so treat it as practical advice rather than a factory spec.

Twin engines, trolling on one

Same answer on a twin-screw boat. The 71C/72C owner's manual addresses this case by name: freewheeling one prop at trolling speed, with the other engine doing the work, won't damage the idle side's gearbox. Run the working engine, let the idle shaft spin free, and that transmission is fine sitting in neutral with the boat underway.

Not for ZF or Hurth

Every statement above comes out of Velvet Drive's own literature and covers Velvet Drive transmissions specifically. We don't have a documented ZF or Hurth freewheeling policy on file. Velvet Drive's installed-angle limits are a related example of the same caution: no more than 15 degrees at rest, or 20 degrees bow-high while running under power, because a steep angle combined with a low oil level can let the pump suck air. That's about how the transmission sits in the boat, not about heel while sailing, but it's the same underlying reason the oil-level condition matters. If you've got a ZF or Hurth gearbox behind a sailboat auxiliary, check that manufacturer's own manual, or call us, before assuming Velvet Drive's freewheeling language carries over.

Related reading

• Velvet Drive vs ZF/Hurth
• 71C series
• 72C series
• Maintenance by model