Saildrive - for and against

[prv]

But You're not allowed to put the Yanmar gears in reverse when sailing and engine is off

...because the torque of a spinning conventional prop causes it to lock up. I've experienced this myself. However, if you have a folding prop, then putting the gearbox in reverse causes the prop to fold and stay folded, and thus there is no torque and no problem.

Pete

 

[JomsViking]

That was my belief as well, but Yanmar tolds us NOT to put it gear even with a folding propeller and if the prop started spinning anyways to fit a shaft brake.

...because the torque of a spinning conventional prop causes it to lock up. I've experienced this myself. However, if you have a folding prop, then putting the gearbox in reverse causes the prop to fold and stay folded, and thus there is no torque and no problem.

Pete

Probably not allowed to post the advisory, but it says:

Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result

 

[prv]

Yanmar tolds us NOT to put it gear even with a folding propeller

They don't say "even with a folding propeller".

Pete

 

[JomsViking]

Sorry for the hijack, but I think this is important.

See quote from Yanmar advisory in my previous post, basically they state that the engine must be in neutral when off - no if's or but's.
And the answer we got from Yanmar when asking for clarification was "even with a folding propeller".

They don't say "even with a folding propeller".

Pete

P.S: I agree that it probably wouldn't hurt the gearbox to put it in reverse with a folding prop, but Yanmar says you should not.
P.P:S: I don't own a Yanmar, but have helped installing/servicing/repairing a few

 

[prv]

See quote from Yanmar advisory in my previous post, basically they state that the engine must be in neutral when off - no if's or but's.

There's a difference between neglecting to mention whether something is OK, and actively saying that it is not OK. The advisory does not specifically say that you mustn't be in gear even with a folding prop. Here's a copy of it: http://portal.mastry.com/bulletins/Kansaki Gears/shift position for sailing.pdf

And the answer we got from Yanmar when asking for clarification was "even with a folding propeller".

OK, I didn't know that you'd asked them directly. But I would wonder who in Yanmar gave that answer. If you've ever worked for a big company you'll understand how much easier it is to give the safe answer rather than the accurate one.

Pete

 

[JomsViking]

I know large Corporations and agree that the safe answer is often given, however the Word must has a very specific meaning in my World:

MUST: This word, or the terms "REQUIRED" or "SHALL", mean that the definition is an absolute requirement of the specification.

So I actually interpret the advisory's:

Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result

the same - hence we asked for clarification

There's a difference between neglecting to mention whether something is OK, and actively saying that it is not OK. The advisory does not specifically say that you mustn't be in gear even with a folding prop. Here's a copy of it: http://portal.mastry.com/bulletins/Kansaki Gears/shift position for sailing.pdf



OK, I didn't know that you'd asked them directly. But I would wonder who in Yanmar gave that answer. If you've ever worked for a big company you'll understand how much easier it is to give the safe answer rather than the accurate one.

Pete

 

[Salty John]

A free wheeling prop slows you down I always lock my saildrive in gear while sailing, I think the foregoing is nonsense I'm afraid.

Actually, according to Strathclyde University, MIT and Michigan Wheel (propeller manufacturers) there is less drag when the prop is allowed to rotate.

I blogged on this a while ago:http://saltyjohn.blogspot.co.uk/2013/07/propellers-what-drag.html