Transmision replacememt

Oct 5, 2010
322
Catalina 30 mkII St. Augustine
I have a M 25 XPB with a Hurth HBW-50 transmission. The transmission need to be replaced and the don't make the HBW-50 any longer. I have been told that the Hurth ZF 10 M will bolt up and is similar to the HBW-100 which is a little more robust. The only difference is the the ZF 10 M is about an inch longer than the HBW-50. Has anyone made such a replacement, and were there any special problems.
 
Apr 2, 2011
185
Catalina 27 Niceville, FL
A Hurth ZF 6 M might be a better choice, if the same size as the old one. A ZF10 is going to make stuffing box access really tight. Either way, stay with the same gear ratio unless you want to change the prop.
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
have you considered calling hurth?
Hurth no longer in business bought by ZF. Have spoken to ZF representatives. Transmission will bolt up that's not the issue gear ratios the same. My question was specific to the Catalina 30 it's engine room and if anyone with a Catalina 30 had a M25xpb with a ZF 10.
 

RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Have you considered to have your current transmission rebuilt?
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
Have you considered to have your current transmission rebuilt?
Yes, did consider rebuild. Price is about the same as new even with upgrade to more robust gearbox.
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
I may have said transmission in my garage. I bought it to go on my W13 but could never locate a flex plate and bell house so scrapped the idea. I née to take a look, think mine is a 1.5:1
 
Nov 7, 2012
678
1978 Catalina 30 Wilbur-by-the-Sea
Here is what I have. It currently has no fluid in it. The folks I Boatguy it from stated it was taken from a boat that had need rebuilt in NC and driven down here to Florida. The owner fell in and something when wrong resulting in the motor getting water locked. New owner replaced the entire kit and they got the trans with very low hours.

That is what I was told, if true who knows.
 

Attachments

Oct 5, 2010
322
Catalina 30 mkII St. Augustine
Here is what I have. It currently has no fluid in it. The folks I Boatguy it from stated it was taken from a boat that had need rebuilt in NC and driven down here to Florida. The owner fell in and something when wrong resulting in the motor getting water locked. New owner replaced the entire kit and they got the trans with very low hours. That is what I was told, if true who knows.
Thanks. You have the HBW 10-2R which would correspond to the HBW150 or the ZF 12 M. I think I'll go with the ZF 10 M which was recommended by ZF distributor for the M25XPB. Again my question had to do with the engine room.
 
Nov 15, 2014
135
Catalina 30T 5830 Green Bay
A Hurth ZF 6 M might be a better choice, if the same size as the old one. A ZF10 is going to make stuffing box access really tight. Either way, stay with the same gear ratio unless you want to change the prop.
I had to replace my blown Hurth tranny at the beginning of the season. It was replaced with a ZF 6M. Engine is Universal M25XP.
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
I had to replace my blown Hurth tranny at the beginning of the season. It was replaced with a ZF 6M. Engine is Universal M25XP.
Thanks. That's what I wanted to know. The gearbox on the ZF 6 and 10 have the same dimensions. George from your post I take it you did not run into any special problems in the replacement.
 

mortyd

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Dec 11, 2004
952
Catalina 30 easy living
if you do change to a zf i suggest you check to see if this transmission, like the hurth, should be in reverse, which was the only positive gear on the hurth, so the faces don't get polished by a turning prop while sailing.
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
if you do change to a zf i suggest you check to see if this transmission, like the hurth, should be in reverse, which was the only positive gear on the hurth, so the faces don't get polished by a turning prop while sailing.
Yes, in neutral or reverse when sailing.
 

mortyd

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Dec 11, 2004
952
Catalina 30 easy living
NO, absolutely not in neutral. in neutral the faces spin against each other and will eventually polish themselves into uselessness. i got this directly from hurth. SAIL IN REVERSE if you have a hurth transmission.
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
NO, absolutely not in neutral. in neutral the faces spin against each other and will eventually polish themselves into uselessness. i got this directly from hurth. SAIL IN REVERSE if you have a hurth transmission.

image-3014391699.jpg

Mortyd - your information is contrary to information in the manufacture's manual. I have attached the section that supports my statement. It is always good to read the manual for one's self so that one can have actuate information.
 
Nov 15, 2014
135
Catalina 30T 5830 Green Bay
Thanks. That's what I wanted to know. The gearbox on the ZF 6 and 10 have the same dimensions. George from your post I take it you did not run into any special problems in the replacement.
The mechanic who did the work did a nice job. No issues. We weren't sure if the issue was an engine or tranny issue so we pulled the engine and tranny. Boom worked good as a support for the chain fall. 6M is about 2" longer than old tranny but that was no issue.

The biggest hassle with taking out the engine was removing the cabinet above it. The stove was put in after all the cabinets. So a short slot was cut in the cabinet for the stove's face flange. I ended up trimming the counter top in order to pull out the cabinet.

Also - as previously mentioned, when sailing the transmission must be in REVERSE.
 
Oct 5, 2010
322
Catalina 30 mkII St. Augustine
<img src="http://forums.sbo.sailboatowners.com/attachment.php?attachmentid=82803"/> Mortyd - your information is contrary to information in the manufacture's manual. I have attached the section that supports my statement. It is always good to read the manual for one's self so that one can have actuate information.
Another source:

image-2212166630.jpg
 

mortyd

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Dec 11, 2004
952
Catalina 30 easy living
thanks for your correction. i agree that printed information in the manual supercedes verbal information given to me by an somebody on the phone at hurth. i no longer need to sail in reverse or worry about it. thanks again.
 

jrowan

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Mar 5, 2011
1,294
O'Day 35 Severn River, Mobjack Bay, Va.
View attachment 82803

Mortyd - your information is contrary to information in the manufacture's manual. I have attached the section that supports my statement. It is always good to read the manual for one's self so that one can have actuate information.
Thanks for clarifying this with actual written proof, not somebody's here say.
This misinformation about putting your transmission in reverse while sailing has been going around this site for too long. It was disproven last time it came up, but it's good to clarify once again.
Putting the engine in reverse will cause more strain to the gears as they will be fighting the great hydrodynamic counter force of water over the prop.
The whole point of neutral is to not let the gears engage, so why would it cause wear?
But the real problem of sailing in reverse is that if you have to start the engine in an emergency, you may forget to throw the trans. in neutral first, which will cause huge strain to the engine while starting, & will likely cause it to stall out.

As far as the replacement transmission if the cost is not much difference I would buy a new ZF, but it's surprising that its not substantially cheaper to rebuild what you have vs. buying new.
 

mortyd

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Dec 11, 2004
952
Catalina 30 easy living
the original, and now wrong, information i got from somebody at hurth was that the faces rubbed and eventually polished and reverse, which is a positive gear, did not. since that made sense, and the owners manual updates had stories about polished faces, i believed until i saw a printed manual. coming from an aviation background i am constantly re-startled how much misinformation is around in the sailing community.