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Prop for 23 ft doral cuddy

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  • Prop for 23 ft doral cuddy

    Hello to all! 1st time poster but avid reader.
    Now I have a query.
    I just recently bought the boat. It has a 5.7 mercruiser with an alpha 1 gen 2 drive. Ratio is 1.47.
    Here is the problem. I ran a high five 14.5x21 pitch prop and couldn't reach wot.
    Then tried a 14x21 pitch 3 blade. No hole shot and takes forever to get on plane.
    Next I tried a 14.5x 19 pitch 4 blade. Hole shot is decent and wot at 4600rpm with a speed ( gps) of 43 mph.

    I was led to believe that the boat should do about 50mph. (Dreaming).
    The problem is as soon as I trim out 1/4 way after plane, the prop grabs air and the engine goes free rev. It doesn't want to trim out therefore I have to leave trim all the way down.
    Is this normal?

  • #2
    If combo planes good leave engine set at neutral trim, just distribute deck weight evenly. Try it out with the prop that achieves the best hole shot and check max wot revs as loaded.

    Happy Boating
    Sea Rider 320, 380 Sibs, 450 Rib, 2 Strokes Tohatsu 5,18 & 30 HP Proud Smokers


    • #3
      In the end, I am looking for a better hole shot and faster to plane. Also good cruise at about 3500rpm. Top speed is not important. I pull waterskiers and tubes.
      Any recommendations?


      • #4
        Welcome aboard!

        Were the props you tried Aluminum or Stainless?

        By the (theoretical) numbers a 19 pitch at 4500 with 10% slip will hit 50.

        Seems like a lot of slip with that 4blade 19p. Some of that could be from not getting much of a trim up.

        You may need some other Doral owners to contribute to see if their experiences are the same regarding the trim. My boat, Bryant 18.8 footer with 4.3 Merc, cannot go much past 1/4 trim without blowing out, there is a sweetspot just past 1/4 (by the gauge) where the rpm's go up a little and the speedo goes up a tad. Go past that with with mine and nothing but foam and speed loss and RPM runaway. Have experienced this with 3 different props. Boat is new to me this season, no idea if this is really normal or not for this hull.

        As a casual observer, I would think a 19p 3blade in Stainless should show some good performance for what you want to do with the boat, might have to watch the RPM's at full throttle.


        • #5
          Thx for the reply. Mercruiser prop selector dialed me into a 4 blade 14x19. I was thinking of going 14x17 also 4 blade.
          By the way the 5 blade was ss and the other 2 were aluminum.
          I am more concerned with the planing.
          Also, I had a 21.5 ft bow rider with a 4.3lx and with a 19 pitch 4 blade the boat ran 45 mph. With a 21 3 blade it ran about 47, but would take long to plane. Thx


          • #6
            A 4 blade 17 pitch will plane faster that combo than a 19 pitch. A matter to test under a wot trial and check max wot revs as loaded. If engine over revs a bit, just throttle less, can compensate over revving adding more load if like running full hammer down..

            Happy Boating
            Sea Rider 320, 380 Sibs, 450 Rib, 2 Strokes Tohatsu 5,18 & 30 HP Proud Smokers


            • #7
              Hi there.
              I can advise and assume with fair certainty that a 21" of any number of blades is too much for you. I have an 18ft boat that will weigh less than yours, same if not more power and the same ratio.
              I run a perfectly dialled in 19" prop.
              So I'd assume you would need a 17, most likely or you may get away with a 19" for good top speed, but terrible hole shot.
              I'd try out a decent 17" stainless 3 blade and see how she goes.


              • #8
                Sign up today
                Finally went with a 14.5x17 4 blade.
                Hole shot much better and I am getting 44 mph wot at 4800. The boat planes faster, and it handles better in rough waters.
                Thanks for all the replies.