Search the Community

Showing results for tags 'inboard motor'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • General Boating Discussion
    • Boat Topics and Questions
    • Bottom Paint Discussions
  • Product Categories
    • Abrasives
    • Anchoring and Docking
    • Apparel
    • Cleaning and Polishing
    • Electrical
    • Electronics
    • Engine Room
    • Epoxy and Adhesives
    • Fasteners
    • Fiberglass Supplies
    • Fishing Tackle
    • Gifts and Books
    • Hand Tools
    • Hardware
    • Marine Supplies
    • Paints
    • Paint Supplies
    • Plumbing
    • Power Tools
    • Storage / Organization
    • Safety
    • Tapes
    • TotalBoat Products
    • Trailer Parts
    • Varnish - Frequently Asked Questions
    • Wood, Foam, Starboard

Found 1 result

  1. Hi, I'm building a 19' motorsailer with an inboard engine. It is the Atkin design "Surprise". The hull is made, as well as the decking, and it is time to mount the motor. I have a very nice Kohler, v-twin, 30 HP water cooled, fuel injected, non marine gas engine. I also bought a nice transmission, a PRM80. The problem is, I need a 1:1 ratio transmission, not the 2:1 of the PRM. I want to cruise the motor at 2400 RPM (3500 max rpm), and the 10" prop I have needs 2400 RPM to reach the design top speed of 20 MPH. I thought I could change the prop pitch to account for the reduction in RPM, but found it would require an extreme pitch and would have too much water slip. The only solution I see is to 1-find a transmission with a 1:1 ratio (which I have as yet not come across) or 2 - increase the RPM between the motor and transmission in some way. I have explored various belt designs, but at high max RPM 2 x 3500 = 7000, and the 20 to 30 hp, and the constrained space, I need either multiple V-belts, or synchronous belts, which become quite pricey and complicated to mount and couple to the motor and trany. Does anyone know of a 1:1 trany that will provide neutral and reverse? or have a suggested solution? Eric