Mainship pilot 34

Kuno · 10-19-2021, 10:51 AM

Hi, I'm a new member. I just purchased a Mainship Pilot 34 soft top with a Cummins 310hp engine 2800 rpm max. Does anyone know what the original prop specs would be for this boat? It is currently over propped and won't get up on a plane.

Comodave · 10-19-2021, 11:01 AM

Welcome aboard and congrats on your new boat. Not familiar with that boat so I don’t have any recommendations on the prop. Is the bottom clean?

Kuno · 10-19-2021, 11:41 AM

The bottom is clean. The boat is in fresh water/great lakes. It has a Cummins 5.9L 2800 RPM 310HP engine. The prop diameter is 24 inches on a 2" shaft. Prop calculators suggest a 24x19. Prop shops suggest a 24x24 with a DAR of 70%, or a 24x23 with a DAR of 81%. Any pilot 34 owners out there?

DavidM · 10-19-2021, 12:52 PM

I owned a Pilot 34 for five years but it had a Yanmar 370 hp single. The Cummins that you have was somewhat rare, but I hope you get a response.

Unless a mistake was made and Mainship installed the prop for the 3,300 Yanmar on your boat, I am surprised it is over propped and won't plane. Planning on mine was about 12+ kts. How fast will the engine turn, both in neutral and in gear? Your throttle stop may not be allowing full throttle. Also check that the turbine spins freely. It may be dragging and limiting power.

I am sure that if it is a new purchase then the bottom and prop should be clean. Otherwise.....

David

Kuno · 10-19-2021, 01:35 PM

The first owner put a higher pitch/diameter prop on it to improve hull speed efficiency. This overloads the motor and limits rpm to 2400, but gets 8kts @ 1400 at 1.8gph. I will be ordering a new prop that will allow 2800 rpm, I just don't know exactly what to order. My options are a Michigan DQX 24x24, a HyTorq 24x24 with DAR of 71%, or a Conquest 24x22.5 with DAR of 81%

jleonard · 10-19-2021, 01:40 PM

Gear ratio Prop WOT rpm
3 26x28 2900
3 26x31 2800

This data is from the old Mainship owner's Yahoo group that I used to moderate. We only had 2 pilot 34s with a Cummins that responded with data at the time.
I can only offer it for it's face value as I did not own one of those models.
They were both 2000 model year boats.

I hope this helps.

Kuno · 10-19-2021, 02:02 PM

Thanks,
That sounds about right for a three blade, I was referring to four blades 24x24 DAR 70%. Perhaps the three blade has less interference with the skeg creating less vibrations.

jleonard · 10-19-2021, 02:31 PM

Normally a 4 blade would reduce vibration.

Kuno · 10-19-2021, 02:41 PM

The full bronze skeg apparently causes vibrations with a four blade. Works better with a 3 or five blade.