I replaced the Hurth HBW100 transmission on an 18-hp Universal diesel I
owned a few years back. The original transmission simply refused to
engage in forward. Reverse, OK. I was told at the time that replacement
would be almost as cheap as rebuilding. Maybe, maybe not. Now, I have
another boat with an HBW100 transmission. The previous owner had
trouble with the original unit. He replaced it, and the new
transmission did not perform well. Hurth replaced that transmission
ultimately. He sold the boat to me, and now I'm having trouble with the
second new transmission, although it has very few hours. Is there a
problem with these units I don't know about? Is there another make of
transmission that would slip seamlessly into the hole left by a Hurth
transmission? BTW, for the earlier poster: Replacement isn't hard if
you can get at your unit. I think folks have already made that point.

I'm not terribly impressed with Hurth transmissions. I had a 100 mated to a
35hp Perkins in my Westsail 32 that failed after only a couple of hundred
hours. I had it rebuilt, and then it failed again. Thinking the
transmission was simply too lightweight to shove the Westie around, I
replaced it with a 150, a much huskier transmission. (None of these
shenanigans were covered by Hurth, btw.) That seemed to do the trick, and
two subsequent owners of the boat, as far as I know, have not had any
further problems.

We now have a Victory Tug with a 150 hp. Cummins and a Borg Warner Velvet
Drive transmission: a truly honkin' gearbox.

Bottom line: in my experience, the Hurth transmissions are at least suspect.

Dick Behan
M/V "Annie"


"Jim" wrote in message
ups.com...
I replaced the Hurth HBW100 transmission on an 18-hp Universal diesel I
owned a few years back. The original transmission simply refused to
engage in forward. Reverse, OK. I was told at the time that replacement
would be almost as cheap as rebuilding. Maybe, maybe not. Now, I have
another boat with an HBW100 transmission. The previous owner had
trouble with the original unit. He replaced it, and the new
transmission did not perform well. Hurth replaced that transmission
ultimately. He sold the boat to me, and now I'm having trouble with the
second new transmission, although it has very few hours. Is there a
problem with these units I don't know about? Is there another make of
transmission that would slip seamlessly into the hole left by a Hurth
transmission? BTW, for the earlier poster: Replacement isn't hard if
you can get at your unit. I think folks have already made that point.

R.W. Behan wrote:
I'm not terribly impressed with Hurth transmissions. I had a 100 mated to a
35hp Perkins in my Westsail 32 that failed after only a couple of hundred
hours. I had it rebuilt, and then it failed again. Thinking the
transmission was simply too lightweight to shove the Westie around, I
replaced it with a 150, a much huskier transmission. (None of these
shenanigans were covered by Hurth, btw.) That seemed to do the trick, and
two subsequent owners of the boat, as far as I know, have not had any
further problems.

We now have a Victory Tug with a 150 hp. Cummins and a Borg Warner Velvet
Drive transmission: a truly honkin' gearbox.

This gearbox is now the ZF 10 M

The HBW 100's torque rating is pretty low. For a 2.045 ratio, the
maximum HP / RPM is 38 HP @ 3000 RPM. So while a 35 HP / 3000 Perkins
may just be under the maximum rating, if you miss the footnote you
might be in trouble, depending on the number of cylinders.

Note: For all "M" (Mechanical) transmissions reduce power capacity by
the following shock factors: 1 cylinder engine ÷ 1.25, 2 cylinder
engine ÷ 1.20, 3 cylinder engine ÷ 1.15"

The "Pleasure" rating isn't very high either:

"Highly intermittent operation with very large variations in engine
speed and power
Average engine operating
hours limit: 500 hours/year
300 hours/year for mechanical gearboxes"

Translation - don't expect too much at this rating. Don't run it all
day at full power.

Here's the ratings page:
http://zf-marine.com/ZFR/Transmissio...ngs&GN=ZF_10_M

We had one on a 23 HP, 3000 RPM Isuzu. Put 1800 hours on it over 4
years. Never hiccuped. I suspect that the box is just undersized for
that size engine

Evan Gatehouse