HBW-5 Gear ratio

[kvk]

The original Hurth HBW-5 trans stopped working in forward and I removed it this week for a replacement or rebuild. The case is stamped HBW-5 2R, i am assuming the 2R is reduction ratio. The transmission mechanic wants to sell me a 1.5 reduction gearbox, and my question / analysis request...how will the 1.5 reduction ratio effect the boat? The sailboat's L.O.A. = 29'11", L,W.L. = 25-ft, 10-ft beam, draws 5.75-ft, uses a Universal 5411 - 12HP, 2 cylinder inboard diesel engine, prop shaft is 1.06-inch diameter, dripless stuffing box, and a folding Martec two bladed prop, (LH 15DX 9P-2), displacement is 8800#.

Any help is greatly appreciated...

Kevin

Not sure if the 2R stamp shows the reduction ratio, but ZF / Hurth has manuals available to tell you that.

Do´nt change the ratio if you are fine with the existent! For what?

And choose your mechanic with more care.

Regards
Richard

Regards
Richard

[kvk]

The ZF manual is mute on the meaning of 2R stamp. However, at the end of the manual, there is contact information for ZF in North America...i will give them a call next week, thanks Richard.

[FAST FRED]

Hurth's SUCK ,
\
replace it with a similar Hurth of one or two sizes larger, or best ,

go find a used rebuilt Twin Disc , and never have a problem again.

FF

[kvk]

Update::

I am almost finished with the transmission related work. The rebuild took a week, and it is back in the boat. What i did learn, was the prior owner(s) was using the reverse gears to move the boat forward...the 5411 engine is a counterclock wise rotation, the HBW-5 was clockwise and would need a right-hand prop. The Martec on the boat was a LH prop, effective in moving the boat forward when the transmission was in reverse gear! I have a RH prop to install next week, and the nightmare has ended. At the end of the day, I gained a rebuilt transmission, full use of forward gears, and access to the port side of the engine compartment...and learned alot more about my sailboat. Its time to raise the main and set the foresail.