Prop for Catamaran Party Kat

[Tmtaber]

Good day all. I am a first time boat owner and I need help. Here's my situation:

1. 2006 Catamaran Party Kat 26' with square-bottomed fiberglass pontoons.
2. Weighs 2800 lbs dry, 3900 lbs with engine, 26 gal of fuel, two adults and gear.
3. 2006 Suzuki 70 hp 4 stroke with throttle range = 5000-6000 rpm.
4. WOT is 5000 rpm with a Solas 4411-140-11 3-blade prop (14 " diameter X 11 " pitch). Prop is in very poor condition, with one blade missing chunks of metal and another rounded over.
5. 10 mph max GPS speed.
6. There is no change in RPM or speed when trimming the motor up or down.

What I'm asking is should I go down in pitch or possibly change to a 4- blade prop? I'm not looking for racing performance, as I know it's a heavy boat, but I feel I can do better that 10 mph. The AV plate sits about 1 " above the bottom of the pontoons and has no further adjustment to raise it any further. Any help would be appreciated and I thank you in advance.

 

[Sea Rider]

You should have tached current starter prop well in advance before being shot to check if engine revved at least middle to max wot rpm range factory stated as currently loaded and then go from there selecting a less pitch to pull wot revs if in need.

You should always go for a prop maximization when new engines has ended their break in period or when buying second hand combos to suit your particular load and boating preferences.

Now the bummer is : Buy exact same new prop or one with less pitch ?

Happy Boating

 

[Tmtaber]

My wife and I just purchased the boat 3 weeks ago and the prop was in this state when we bought it.

 

[Sea Rider]

Terrible to read that, will need to check with a prop calculator a starter prop for that combo and then go from there maximizing less pitch props to pull wot rpm up if in need towards max wot rpm range that's much preferred.

Happy Boating