24FT Tritoon - Honda 200

Discussion in 'Props' started by Southerntoon, May 19, 2014.

  1. Southerntoon
    Joined: May 2014
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brandon, MS

    Southerntoon New Member

    Boat: 24FT Fisher Tritoon
    Motor: Honda 200 - Target RPM Range is 5600-6000. Does not create 200HP until 5500 RPM.
    Prop: Stainless 14 1/4 x 17 4-Blade


    I keep the boat in a wet slip so there is some growth on the toons. Last month we took it out of the water and cleaned the toons. Put it back in the water, full tank of gas 30 gallons and 500 lbs of people and at WOT we are 5100 rpms at 41 mph. So I am still not creating enough rpms.

    Yesterday with a full tank of gas and 1000 lbs of people the boat ran WOT at 5000 rpms and only 25-27 mph.

    Motor Height Problem ? Prop Size ? Prop 3 Blade VS 4 Blade?

    Any Thoughts?

    Thanks
    Southerntoon
    Brandon,MS
     
    Southerntoon, May 19, 2014
    #1
  2. fredrosse
    Joined: Jan 2005
    Posts: 439
    Likes: 81, Points: 38, Legacy Rep: 56
    Location: Philadelphia PA

    fredrosse USACE Steam

    About 10% less pitch should bring the RPM up to the full power level. 41 MPH = 3600 FPM at 25% slip on the 17 inch pitch prop you would have 2546 prop RPM. Is the Honda 2:1 gear ratio? if so that matches 5100 engine RPM @ 25% slip, a reasonable combination for OK propulsion numbers.

    With the heavy load, obviously slip is much worse. 26 MPH = 2288 FPM at 35% slip on the 17 inch pitch prop you would have 2500 Prop RPM, evidently corresponding to 5000 RPM on the engine. Perhaps the hull resistance is very poor at this speed and load condition.

    The other issue is prop diameter and blade area, is that proper for your boat? Difficult to address specifics without some firm comparison/experience numbers for the same hull. Is there any air ventilation of the prop?
     
    fredrosse, May 26, 2014
    #2
  3. Southerntoon
    Joined: May 2014
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Brandon, MS

    Southerntoon New Member

    Yesterday I raised the motor up by adjusting the Jackplate about 2/3 of the way up. It seem to pick up a few hundred rpms and about 2 mph to 27 mph with about the same 1100 lbs of people etc. Trimming now only about 20% up on the gauge and it seemed to be ventilating above 5200 rpm and mph would start going down. Not sure how much trim I should have to play with on a tritoon if the motor height is correct?

    All Toons have lifting strakes. Toons are 26" Hull weight without motor is suppose to be 2860lbs

    Honda 200 spec sheet says 1:86 Ratio

    Pics from yesterday - a few people have said motor is still too low. Also most have suggested going to a 15 to 15 1/2 x 15 3 blade prop. A few suggest 15 to 15 1/2 x 17 - keeping the pitch up for top end speed. A few others have suggested a 14 3/4 x 16 mercury enertia prop.

    Yes I believe the prop/motor is ventilating when I trim up and rpms hit 5400-5600 because the mph start going down and then go back up when I trim back down to 5100-5200 rpm. However I am not trimming much and not sure if should have alot of trim to play with or not and how that corresponds to the present motor height.
     

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    Southerntoon, May 27, 2014
    #3
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