Prop Help

[1970Columbia34]

Well we hit the water today with the new motor, motor seems to run great, with the motor in neutral it would rev to 3000+, in gear we could only get about 1800 rpms and about 3.5 knots . the motor is a Universal M25xp, Trans is a Hurth V-drive with a 2.99:1 ratio, and the prop is a new Martec fixed blade 16dx16p RH. Its looking the the prop has to much pitch and need to tame it down some, I have a call into Martec but wanted to get your guys opnion on this from your personal experiences. 16" is the max we can swing. Any info would be great and thanks in advance.

Scott

[sailingdog]

16 x 16 is a pretty big prop for a 23 HP motor. I am estimating that you'll probably want more like a 10-12" pitch for the prop, rather than the 16" pitch you've got currently. A good prop shop should be able to give you better numbers.

[1970Columbia34]

yeah after our motor up the river yesturday its way to much pitch. with our old 22hp palmer p60 we had a 16x11, i figure the diesel should be able to handle more pitch but i thin Martec went to far with it. we still have or 16x11 and my buddy has a 16x12 folder as well. i am wondering what martec will offer to do with the prop we spent $500 on...

[sailingdog]

Drop down to a 16x12 or the old 16x11 you have and your boat will be much happier. Martec blew it with a 16x16 prop for a boat with that size engine and gearing.

[1970Columbia34]

i am wondering if the 16x11 will not be enough. the old motor had a 2:1 gear ratio so at 2200 rpm the prop was spinning at 1100, and with the new gear ratio of 3:1 we would have to run the new diesel at 3300 rpm to get that prop speed. which is to muxh for the motor. i agree martec blew this one but i won't bash them just yet tell i see what he is willing to do for me.

[Fstbttms]

Originally Posted by 1970Columbia34

i am wondering what martec will offer to do with the prop we spent $500 on...

If you're lucky, they'll send you some new, differently pitched blades to install. That's a 15-minute job in the water.