Lock the prop or let it spin? 386

[datasailor2]

So last year I had to replace the cone drive in my Kanzaki KM3A and really don't want to do this again prematurely. After reading comments I feel validated about my practice when I sail with the motor shut down. Now, what is collective advice on transmission setting when motor sailing? At times I find the wind is perfect for a sail (not talking about rails in the water sailing), but also have need to run my Yanmar 3GM to charge batteries after long time on hook. My current practice is to leave tranny in forward setting and reduce engine throttle to find sweet spot where prop shutter is minimized. Look forward to your opinions.

 

[SG]

With the motor runny while motor sailing? First, to get your alternator to "put-out" adequate amps, you'll need need to do more than just 1800 rpm if you want to charge the batteries. (It depends on your alternator, it's voltage regulator, time you want to leave the engine running, and your "need" for recharging.)

You probably aren't doing any harm by running the engine at low rpms, but keep in mind that fuel usage relates to load, not only to RPM. I believe, if you're motor sailing and the prop isn't loading-up, you're difference in fuel use is pretty low by simply running (say) 1800 rpm.

The approach I'd use, just talking about it: i) if you were sailing alone and your speed was, say, 5 knots. Then engaging the engine at an RPM that didn't move the speed up very much at all really is doing not much more to fuel consumption than idling the engine. In very low speed conditions, then the engine needs to get up to 1600-1800 RPM, or your just aren't putting-out many AMPS. IF you're charging along at near "hull speed", then you'll not have to bring the engine up to 2300 RPM to get the alternator turning.

You transmission should be cooled because you're engine/transmission cooling system should be doing it's job with the engine on.

 

[jssailem]

just gotten off sailing a charter boat

How was the adventure in our PacNW waters. Perhaps starting a new message or contributing to the PacificNW message.

 

[Terry Cox]

Yanmar says to place our Kanzaki transmission in neutral while under sail to allow shaft to rotate. Sailing in gear places too much unwanted pressure on transmission parts, so they say.

 

[datasailor2]

Thanks for the advice SG and other skippers.