HBW-5 Gear ratio

Discussion in 'Diesel Engines' started by kvk, May 22, 2010.

  1. kvk
    Joined: May 2010
    Posts: 3
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    Location: Baltimore MD

    kvk New Member

    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
     
  2. apex1

    apex1 Guest

    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
     
  3. kvk
    Joined: May 2010
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    Location: Baltimore MD

    kvk New Member

    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.
     
  4. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    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
     

  5. kvk
    Joined: May 2010
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Baltimore MD

    kvk New Member

    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.
     
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