Hello
I have a 20ft cuddy cabin boat. The engine is a 2.5l ford turbodiesel that ive built myself and mated to a alpha one drive with a 1.5 gear ratio.I dont know the output but would quess somehwere in the 130hp range. I built this engine to economically cruise,its not meant to run wot and im not that interested in it anyway. Fuel consumption is very low,I have not made a exact measurement but somewhere in the 13-14l/h region cruising at 27-28mph. I have tried a few different propellers and still not 100% happy and looking for suggestions.
Ive tried a solas hr titan 4 in both 17 and 19 pitch.The 19 pitch would barely plane but when it did the cruise was excellent, I dropped down to a 17 pitch. This prop was quite good but had some downsides,it would cruise at 25mph at 2800rpm, holeshot was quite good and could pull a wakeboarder easily with a few people onboard. The quality of the propeller was quite poor,it was out of balance and even the hub was out of round(brand new prop),my overall impression was that it was quite a heavy prop that requires alot of power to spin it.It would max out at 33mph and rougly 3100-3200rpm. To little wot rpm meant i was labouring the engine and going down in pitch would cruise speed even more. It had alot of stern lift and the boat would porpoise quite easily when trimmed. One problem with the 4 blade titan was that it would not slip, i had problems getting the engine up in rpm to start building boost and also power.
Next and current prop is a mercury vengeance 19 pitch, quality of this prop is very good. Compared to the titan the vengeance slips alot during planing which makes the engine get up to the "powerband" alot faster,still planing speed is rougly the same.During planing the nose of the boat goes up towards the sky which it never did with the titan.At 2800rpm im cruising at 26mph and at 3000 at 29mph. Weirdly enough although this prop doesnt have cup or rake it allows me to trim the nose up alot more. It tends to slip alot and this is confirmed using the slip calculator(18%).If I wot it the rpms jump straight to the governor max speed of 4000rpm, speedwise I saw 36mph but it would go more if I would keep it at wot. Also at cruise the aft tends to sit quite deep in the water compared to the titan.
Im quite happy with the current vengeance,ideally I would like a prop to get just a bit more speed out of the same rpm and maybe get the slip numbers a little bit down. Any suggestions on pitch or propellers?
Fyi I would not recommend the solas propellers, at least not for the big boats, the quality is really subpar when compared to the mercury props. I do have a solas saturn on a 15hp suzuki that is really flying after some modifications and refinishing, so maybe for the smaller boats they are ok.
I have a 20ft cuddy cabin boat. The engine is a 2.5l ford turbodiesel that ive built myself and mated to a alpha one drive with a 1.5 gear ratio.I dont know the output but would quess somehwere in the 130hp range. I built this engine to economically cruise,its not meant to run wot and im not that interested in it anyway. Fuel consumption is very low,I have not made a exact measurement but somewhere in the 13-14l/h region cruising at 27-28mph. I have tried a few different propellers and still not 100% happy and looking for suggestions.
Ive tried a solas hr titan 4 in both 17 and 19 pitch.The 19 pitch would barely plane but when it did the cruise was excellent, I dropped down to a 17 pitch. This prop was quite good but had some downsides,it would cruise at 25mph at 2800rpm, holeshot was quite good and could pull a wakeboarder easily with a few people onboard. The quality of the propeller was quite poor,it was out of balance and even the hub was out of round(brand new prop),my overall impression was that it was quite a heavy prop that requires alot of power to spin it.It would max out at 33mph and rougly 3100-3200rpm. To little wot rpm meant i was labouring the engine and going down in pitch would cruise speed even more. It had alot of stern lift and the boat would porpoise quite easily when trimmed. One problem with the 4 blade titan was that it would not slip, i had problems getting the engine up in rpm to start building boost and also power.
Next and current prop is a mercury vengeance 19 pitch, quality of this prop is very good. Compared to the titan the vengeance slips alot during planing which makes the engine get up to the "powerband" alot faster,still planing speed is rougly the same.During planing the nose of the boat goes up towards the sky which it never did with the titan.At 2800rpm im cruising at 26mph and at 3000 at 29mph. Weirdly enough although this prop doesnt have cup or rake it allows me to trim the nose up alot more. It tends to slip alot and this is confirmed using the slip calculator(18%).If I wot it the rpms jump straight to the governor max speed of 4000rpm, speedwise I saw 36mph but it would go more if I would keep it at wot. Also at cruise the aft tends to sit quite deep in the water compared to the titan.
Im quite happy with the current vengeance,ideally I would like a prop to get just a bit more speed out of the same rpm and maybe get the slip numbers a little bit down. Any suggestions on pitch or propellers?
Fyi I would not recommend the solas propellers, at least not for the big boats, the quality is really subpar when compared to the mercury props. I do have a solas saturn on a 15hp suzuki that is really flying after some modifications and refinishing, so maybe for the smaller boats they are ok.