Propeller specification 12 Meter

[Dutchman59]

Hello, thanks for letting me joint the group. I recently bought a 1988 Trojan 12 Meter International Flybridge with twin 6-71 @ 450 HP.
The Boat was sitting for a couple of years due to the owner passing away as a result I have no history on anything. We surveyed the boat and it did well for the age. One of the issues I have is with the RPM. Currently, I can not get much over 2000 RPM (=24 knots). I am cruising the boat @ 1800 RPM what gives me 20 to 21 knots.
The Tachs are new, and I am aware that the governors could be limiting. The boat came with 2 sets of propellers (24 x 26 with a cup installed) and a spare set 26 x26.
I am wondering if anybody in the group would know the proper factory spec for this set up.

Thanks in advance

[prowlersfish]

Is the bottom clean ? I would get a photo tach and check the rpm first. Do you check the no load rpm in neutral ? Under load you should turn 2500-2550 .
It should be in your manual . If you don't have one and no one post the size contact Bob Beacon marine he can tell you . Also You can get the manual from them .

Got the info 26x27 3 blade From the factory


Sweet boat

[prowlersfish]

No load wide open rpm should be about 2650 . Engine should be warmed up . And tach checked

[Dutchman59]

Thanks for the info, will look for a manual

[prowlersfish]

Since you are slightly under the factory size , (26x27 3 blade ) Are you 3 blade ? I would check the Tachs . you can get a photo tach cheap on line .

[Dutchman59]

Yes have 3 blade propellers, Tachometers are new and calibrated proper.

[prowlersfish]

Has the the no load wide open rpm been checked ? This will tell you how the gov is .

Some boats need to be a few inches under spec on the props , almost all need to be a inch under as a min.

[Dutchman59]

No testing right now, boat on the hard for the winter

[maxj113]

Wow, awesome boat! It looks brand new...