Slipping transmission?

[Jim Hardesty]

I have a Maxi-prop, works great.  I've cruised with boats equipped with the folding props, they seem to struggle motoring through Lake Erie steep choppy waves.  FWIW I think it's the small blade area.  If I have any qualms recommending the Maxi-prop it's the prop walk.  For me it's something I'm used to and not a real problem.
Jim

[glennd3]

BA,   I read the thread where you were having your prop checked back in January and then more recently about your trans slipping.  Did you have it fixed and was there a problem with it that could have caused the problem you have now? How did you confirm hitting the log? Just asking because maybe there is another issue to consider.

[Breakin Away]

BA,   I read the thread where you were having your prop checked back in January and then more recently about your trans slipping.  Did you have it fixed and was there a problem with it that could have caused the problem you have now? How did you confirm hitting the log? Just asking because maybe there is another issue to consider.

It's 100% certain that all three are completely separate issues.

My prop was checked proactively - there was nothing wrong with it, I just wanted it checked out. Ray at Atlantis Prop did find one blade was pitched only 8", so corrected all blades to 9".

The question about transmission slipping was noted on the hard, as I was rotating the prop and shaft to put a final coat of paint on it.  It had nothing to do with the prop at all. In fact, I rotated the shaft by putting a pipe wrench on my shaft anode to turn it, since Ray warned NEVER to block the prop blades.

The boat was dropped in the water yesterday and running 100% perfectly until the incident with the submerged log, probably a railroad tie. When I looked astern, I saw the end of an ~8"x8" square cross section popping through the water. There is no question that I hit something that caused the problem, and the surveyor will confirm it tomorrow or the next day.

Assuming the prop needs replacing (which I'm 95% sure of), I will probably apply insurance toward a 3-blade 15"x9" Flexofold, assuming there's sufficient clearance between shaft and rudder. Shaft or strut are probably damaged too for reasons I already explained.

[Noah]

Breakin'-
Reminding you of A fairly recent post with pics where we discussed props and struts. I am happy with my 15 X 10 (not 15 X 9) Flexofold 3-blade on my smaller 25XP engine. Also, I have recently replaced my strut (for another unrelated reason) and would be happy to share the procedure and details if you are interested. Just PM me.
http://c34.org/bbs/index.php/topic,10092.msg77555.html#msg77555

[Breakin Away]

Thanks for the reminder. I'll go back and look at it again.

I remember that you had 15"x10" prop on a smaller motor, but Ray at Atlantis reminded me that the transmission gear ratio has a big impact, and could negate the larger motor. What is the gear ratio of your transmission. My Hurth HBW100 is 1.79 in forward.

I was planning to test full throttle RPMs on that trip as soon as I got into close range of my final destination. Unfortunately I did not make it far enough to run the test, and now I'll likely have to choose a new prop without that data.

By the way, I had put an anode onto my strut before launching. We'll see what kind of condition the strut is in soon.

[Noah]

Hurth 50  2:1

[Breakin Away]

Hurth 50  2:1

Thanks, I'm rereading a lot of the stuff there which I had seen before, but it was less urgent at the time, so I had forgotten some of it. I had planned to spend this season with my refurbished 15"x9", do more extensive testing of motor RPMs with my strobe, check shaft RPMs vs. spec gear ratio to ensure there was no slipping, then make a decision on re-pitching. Now I'll almost certainly have to buy a new prop without that benefit. Almost makes me default back to another Michigan Sailer prop rather and save my $2100 for a future Flexofold after I have my data.

Sorry if my questions were repetitious - I need to go back and re-read a bunch of stuff before asking any more questions.

[Noah]

I would say it is all moot until you survey your damage. If your prop is damaged you may be be able to recondition it. I keep my old 15 x 9 Michigan 3-blade as a spare. Although it is not currently fitted/lapped to match my new S.S. shaft, it gives me comfort to keep it in case something crazy happens?!?

[Bill Shreeves]

I have a ZF 10M gearbox which, I believe is 2.05/1 and a 15x10 Michigan Wheel Sailor Prop on my M25XPB which is 26 HP.  It's been running very well.