helievacpilot

Just finishing up the basic hull work on a 36in Dumas SK Daddle and I had a radical idea. I'm an old-school kind of guy and my favorite car is the 1969 Hurst Olds (classic muscle car). Since I am not interested in racing the boat, I got the idea to finish it out to look as if Oldsmobile had built a boat to mirror the car. Paint scheme/hood scoop/rear wing/windshield/etc.. will be built into the boat along with marine hardware details to mimic a full size boat. I would like to finish out the interior, but a big motor sticking out right in the middle kind of kills the effect. But I do want to stay nitro instead of electric. Considering that the boat will be heavier than stock and sticking with the "I've got to be different" theme, I bought a K&B .65 Sportster engine and am converting it to marine use and a Davis Diesel head. I plan on splitting the exhaust and running dual tips out the back just below the water-line. I think that the combination of the Diesel sound/low RPM@idle/exhaust routing should give a great exhaust note. Now to the question of props. Because I am now diesel and the Sportster engine will not turn the rpm's of a marine motor, I need to go to a higher pitch. I would also like to go with a 3-bladed prop to stick with the "full size" theme. I said I do not want to race, but I still want to go fast. With the lower rpm's but extra displacement and Diesel torque, what would you guys recommend in a 3-bladed prop (dia. & pitch) to make this thing get up and move!
Thanks for your input - Bill

TwinJetMax

That would all depend on the final weight of the boat and the type of drive you are using. One could assume that you will be mid-mounting your engine and have a solid angled shaft. For the scale look you want the prop to be the diameter. People aren't going to notice if the pitch looks wrong. Make sure you buy a submerged drive prop as it will be better suited and stop your motor getting bogged down. Some people will buy multiple props at once and test them all at the same time to get noticeable changes.
I like the sound of the project, love to see some pics at the end.

helievacpilot

I will be mid-mounting the engine. My plan is to run a flex-dirve to a submerged prop right below the transom. I'm not concerned about the scale look of the prop, dia. or pitch. I just want the prop to take advantage of the additional low-end torque of the engine. I'll try to post some progress pics as I go.
Thanks - Bill

f16man

Just a heads up on the k&b sportster engine, those have bushings holding the crank and not ball bearings as in most all others made, I don't think that the bushings are gonna like marine service.

helievacpilot

Why is this? Can they be replaced with ball bearings?
Thanks - Bill