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Lock the prop or let it spin? 386

Discussion in 'Ask A Hunter Owner' started by Hamish_s, Aug 19, 2017. Add this thread to a FAQ

  1. SG


    Joined Feb 11, 2017
    978 posts, 152 likes
    J/Boat J/160
    US Annapolis
    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.

    datasailor2 likes this.
  2. jssailem


    Joined Oct 22, 2014
    5,579 posts, 1,882 likes
    CAL 35 Cruiser
    US Salem, Moored Port Everett WA
    How was the adventure in our PacNW waters. Perhaps starting a new message or contributing to the PacificNW message.

  3. Terry Cox

    Terry Cox

    Joined Dec 25, 2000
    3,200 posts, 308 likes
    Hunter Passage 42
    US Shelter Bay, WA
    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.

  4. datasailor2


    Joined May 17, 2010
    16 posts, 2 likes
    Hunter 1983 - 34'
    US Port of Everett
    Thanks for the advice SG and other skippers.