[crokit]

Hello... I have a 40 foot houseboat...weighs about 6 ton ....three pontoons(steel)...I'm using a 1986 70 hp johnson...I believe the prop that is on there now is a 13x14(maybe 14x13 can't remember)that is aluminum...and uncupped.just wondering if there might be a better choice for this type of setup ...thanx

[ufm82]

You want a large diameter, large blade, low pitch prop for a houseboat. You need push and good low speed directional control and a blade like that will work. I'm guessing you are running a 13" diameter prop since it's a 70hp engine. However, without RPM readings no one can tell you if it's a good set-up. If RPMs are too high, you'll need to up the pitch. If they are too low, you'll want to drop the pitch. Houseboats are tough on engines as they really have to work to push that load. I'd be certain to have that engine serviced every season, paying special attention to the LU. Synthetic extreme pressure LU grease would be my suggestion as well. UFM82

[rickdb1boat]

You have a 14" X 13" right now. My toon with a 91' 70HP rude pulls 5900-6000 RPM's with the 14 X 11 cupped prop. Without knowing the wide open throttle RPM's that you are turning now, it's hard to say what will be best on a 6 ton boat...

[crokit]

I checked my wot rpm on the weekend ....it maxed out at 4900...so I assume that I should pitch down...right?

[Dunaruna]

14x11 will see you just about perfect.