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Repowered my Luhrs 360SX with Yanmars, have questions

Discussion in 'Luhrs Yacht' started by Crime Scene, Feb 16, 2026.

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  1. Crime Scene, Feb 16, 2026
    #1
    Crime Scene

    Crime Scene New Member

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    Looking for some help. I have a 1997 Luhrs 360SX that had Volvo TAMD 63 P's in it, 370 HP each. I recently repowered with a pair of Yanmar 6LYE-EPTs at 480 HP. I'm wondering if anyone has the same boat with the Yanmars and if so, what are your performance numbers (cruise and WOT) and what Prop size do you have?
  2. Capt Ralph, Feb 16, 2026
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Yanmars may have a higher RPM operating range.
    Did you change reduction or props during your upgrade?
  3. Crime Scene, Mar 27, 2026 at 5:17 PM
    #3
    Crime Scene

    Crime Scene New Member

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    Sorry, I don't check the site regularly, the gear ration on the new transmissions is 2.43 to 1, it used to be 2 to 1 with the old engines. I have been through several computer programs to come up with the right props but I was hoping someone else repowered my same hull with the same engines so I could pick their brain.,
  4. Capt J, Mar 27, 2026 at 9:50 PM
    #4
    Capt J

    Capt J Senior Member

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    Newer ones had Yanmars, I used to run a 2006 I think it was that had Yanmars but only cruised at 22 knots. I cannot remember HP or anything else.
  5. Crime Scene, Mar 30, 2026 at 10:57 AM
    #5
    Crime Scene

    Crime Scene New Member

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    Thanks for the response, I was running 21-22 knot cruise with the Volvos, I'm hoping to get at least 5 or 6 knots more with 30% more HP.
  6. Capt Ralph, Mar 30, 2026 at 4:36 PM
    #6
    Capt Ralph

    Capt Ralph Senior Member

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    More HP does not necessarily mean lots more speed on an older hull design.
    Torque and traction make boats move.
    I do look forward to your final results so please keep us updated.
  7. Crime Scene, Mar 31, 2026 at 11:42 AM
    #7
    Crime Scene

    Crime Scene New Member

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    I understand, the Torque difference is not quite as high at the HP difference. Almost 30% more HP but only 15% more torque. I hope I am getting the right props which is going to make all the difference. I will let you know.
    chesapeake46 likes this.
  8. DOCKMASTER, Apr 1, 2026 at 11:45 AM
    #8
    DOCKMASTER

    DOCKMASTER Senior Member

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    What props are you going with (manufacturer and type) ? What props did you have before the repower? When I did my repower I was also very concerned with getting the props correct. I didn't do the HP % increase you are doing but I did go from 1.6 trans ratio to 2:1. I also reduced weight and made a lot of other changes. I went from a 4 blade to a 5 blade prop. I selected the Veem Interceptors. And I have to give kudos to Veem because they absolutely nailed it on the first try. At sea trial on my new engines CAT told me not to touch the props as the engine load was perfect. I gained more speed and efficiency then I expected to. Of course, not all improvements are just because of the props but I couldn't be happier with the Veems I have.

    It is critical to give your prop manufacturer as accurate of info on the boat as possible. Weight is important of course, but accurate length at waterline is even more important. Of course your engine/trans stuff is critical as well but you obviously have all that.
  9. Pascal, Apr 1, 2026 at 4:04 PM
    #9
    Pascal

    Pascal Senior Member

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    When I repowered my 53 Hatteras the Cummins dealer had a good local prop shop run the numbers. Their results were spot on.
  10. Capt Ralph, Apr 1, 2026 at 7:51 PM
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    All further notes that a better shop can be very helpful.
    Sadly, These better shops are getting few and far between.

    I can't find a close by shop to help on outboard props. I'm doing better just purchasing new alloy props from Port Supply.
    My big prop shop who I luv very much (TCP), does not want to even talk about out-board wheels.

    Anybody know of a out-board prop shop that can work with me around Satsuma / St Augustine?
    Last edited: Apr 1, 2026 at 8:00 PM