Is you is or is you aint?

[matt ciarpella]

Gentlemen, I am new to all of this including being an owner. Please comment as to whether I have what I think I have. What I got is a pair of volvo supercharge turbo kamd42 motors(230hp) with 2:1 hurth gears, 8 degree down angle.
I built the bunks on 5 degrees to give me 13 for the shaft. Does this sound right? Gears and all.
Next, after looking into these motors it appears that they run at a highter rmp range wot 3600? Every one I speak to says "WHAT?" and now they got me saying it. This seems to throw me off when it gets to wheel size and slip. Boat has 1 3/8" shafts which I think should be ok with a smaller wheel (19-20"). That is my guess
Please hold nothing back.
Matt

[CaptPatrick]

Matt,

Again, welcome aboard!

Actually, I believe the rated wot rpm for the KAMD42 is 3900. Don't be overly concerned with what may sound like a high number rating as opposed to something like Cummins & Detroit with a slower turning rating. Your 2:1 gears are the correct ratio to take advantage of the torque. Like Yanmar 6LPs the Volvo KAMD42 will develop it's max torque at mid range.

Wheel size and configuration are dictated mainly by weight, beam, & length of the boat, clearance between the hull and prop tip, and transmission ratio. In your case, the wheel size is going to be in the 20x22 w/ a #3 - #4 cup on a 4 blade.

Bruce Creamer is our chief mechanic here & probably won't be back on line before Monday. He's the guy to give a more definitive answer. I'm not a mechanic, just mechanically inclined...

Br,

Patrick

[matt ciarpella]

Well I feel better, Thanks for your input. I have been going back and forth with confidence over whether or not this was going to be correct.
Matt