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I am running Cummins qsb 5.9, 230hp hd's coupled to twin disk 502's at 2:1 gear reduction. I have new 19" bronze props with 28" pitch. The problem I am having is I can't get better than 62% load at WOT. The 230 hp engine is rated at 2600 rpm. I can get to WOT with little effort. Seems like I am unde...

Tony, what gear reduction do you have? I am hearing some of my speed problem might be the 2:1 gears I am using. What do you think?

I am running the 230 hp version. What are you getting for speed with your props?

I have a 1970 B31 flybridge with cummins 5.9 QSB's and 2:1 gear box. Can anyone give suggestions on prop size, pitch, cup and anticipated performance with this setup?

Does anyone have access to Bob Lico's "How to build a deck" site?

Any preferences on shaft savers? DriveSaver vs. IsoFlex

We are in the process of repowering our 31 FBC with Cummins QSB 5.9's and we are trying to set the height of the exhausts as they exit the transom. What kind of numbers have people see in water line change after going from the old 454's to the diesel engines? I have also seen some oval shaped exhaus...

Bob,
Thank you. What wall thickness did you go with for the inner and outer fiberglass shaft log tubes? 1/2 a knot is a big increase!

We are looking to replace the bronze shaft alleys on our boat with fiberglass shaft logs due to upgrading to 1-1/2" shafts and was wondering if anyone can recommend what packless shaft seals to use

What is the reason for changing out the bronze bolted up shaft alley's with fiberglass shaft tubes?

Thanks Bob, I realize every installation is different and every bit of info regarding trials and errors of others helps with making decisions without going backwards. Thanks again I like your idea of making wood parts for welder.

Whaler,

after removing the Bertram 454 beds did you cut down the remaing strigers at all? Also, do you have any shop drawings for the aluminum motor risers?

Replacing 454's with cummins 5.9 engines. Anyone have ideas for new bed architecture? I have removed bertram wood sisters already.

Tony/Scott, Thank you for your help. It sounds like 1.5:1 is the way to go and both the MG-5050a and the ZF220A are the gearboxes we are having a hard time deciding between. We currently have a set of twin disk 502's that came with the engines that are 2:1 that when we took them to get serviced were...

We a B31 that we are installing Cummins QSB 5.9 230 HP at 2800RPM engines in and need to get a new set of gear boxes. Any recommendations on what gearboxes (ZF or twin disk) and what gear ratio (2.5:1, 2:1 or 1.5:1) and depending on gear ratio what props we should be running?

My "70" b31 has 1 3/8" shafts. Will struts take 1 1/2" shafts if I replace cutlass bearing?

I have a 1970 31 FB that will be repowered with QSB's. Would like to find someone interested in giving advise on this project. Boat is in Morro Bay out of the water in yard.