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Last seen: 2 days 2 hours ago
Joined: 12/28/17
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Hurth Transmission is "Singing"

I have started to hear the Hurth transmission or prop shaft making a high pitched whine when the boat is in forward and the M25XP is running between 1200 and 1600 rpm.  It does not seem to effect performance and drops away as soon as the throttle is taken above or below those rpms.  ATF was replaced 2 weeks ago with no change.  Any ideas would be helpful.

Dave Pennington
1990 C36Mk1 "PenniMizer III"
Lake Ontario, Sodus Bay NY

Siler Starum's picture
Siler Starum
Last seen: 1 day 7 hours ago
Joined: 4/20/18
Posts: 55

Have you checked the control cable? 
Maybe the settting is changed and the lever is not in the correct ahead/astern position and therefore slipping.

Durk Nijdam
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland
Last seen: 2 days 2 hours ago
Joined: 12/28/17
Posts: 2

THanks Durk,   I will check that out.  I didnt think that would create an issue on a specfic rpm range but, it certainly could have moved over time. 

Last seen: 16 hours 35 min ago
Joined: 9/27/09
Posts: 491

I had a similar problem for a few years but only after just launchng in the spring. Turned out to be the paint on the prop (I used hard on the prop... I know, some peoplefeel that is not good but have been doing it for years ontwo boats). Once it wore off the edges, the high pitch stopped. Maybe you need your prop tuned up as I assume this late in the year it isn't from a reecent coat of paint.


Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

alfricke's picture
Last seen: 2 weeks 3 days ago
Joined: 4/14/09
Posts: 46

Another good possibility is a cutlass bearing going bad. You could dive it and see if there is excessive play in the bearing and look to see if there is any material sticking out. 

Al Fricke
S/V Jubilee
Catalina 36' MkII  #1867
Last seen: 1 week 1 day ago
Joined: 9/17/16
Posts: 28

I had a similiar experience right after I installed a new transmission, tuned prop, new strut, and calibrated prop shaft. Mine would whine/sing loudly at times up to about 2000 RPMs and then go away above that. I thought it might have been the shaft rubbinig instead the shaft log. It seems to have all gone away a year later. I also used to have a whining sound when I was sailing and had transmissionin reverse. At 5 to 5.5 knots, I would hear a low whine or singing sound. The yard said it was a singing prop. Well after a year or so of having the bottom cleaned monthly, I no longer get the singing prop while sailing OR the whining sound while motoring. I think it was the prop- the edges were too sharp.

Simpler Times
1989 C-36 MK I #1004
Redondo Beach, Calif.
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