Shafts thru the transom?

Discussion in 'Powerboats' started by Buck, Sep 17, 2003.

  1. JBAInnovationAS
    Joined: Nov 2004
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    Location: Norway

    JBAInnovationAS Junior Member

    Like the one on the attached picture. Made form available standard universal joints etc. only the big nylon pivot and axle tube are machined, ... and of course it didn't work. Disasterous geometry and flow to the propeller. I am now building a traditional shaft/ submerged propeller setup on this boat. Will let you know speeds etc. when I am done.
     

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  2. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Looking forward to see this project.
     
  3. Steve H
    Joined: Aug 2004
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    Location: S.W. WashingtonState

    Steve H Senior Member

    Here is a better pic of my current set up that is coming out any day. just waiting for the weather to warm up

    Steve H
     

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    1 person likes this.
  4. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Thanks for the better image Steve H don`t we have fun,the things we do.
     
  5. CaptPPan
    Joined: Oct 2003
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    Location: Bellport,N.Y.

    CaptPPan Junior Member

    I have almost the same setup on a 27' Harley. What size shaft do you use and how long is it. I've also had to force feed my stuffing box with water to keep it from burnig up, did you have the same problem?
     
  6. Steve H
    Joined: Aug 2004
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    Steve H Senior Member

    The shafts are 1 1/2". The are about 70" overall length. Yes I did run water pressure lines from the engine blocks to the stuffing boxes. I just drilled and tapped the shaft log assy and installed a barbed fitting, then connected a 3/8" line from the exhaust manifold. Made a huge difference. It also has water pick up tubes that are bolted to the transom, pointed into the shaft exit holes. I had to tighten the stuffing box constantly prior to the waterline install. Other than dock handling, this has been my main complaint about this set up.

    Steve H
     
  7. CaptPPan
    Joined: Oct 2003
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    Location: Bellport,N.Y.

    CaptPPan Junior Member

    I handled my stuffing box problem the same way and now it works wonderfully. I'm only using an 1 1/4 shaft and it's almost as long since my engine is mounted under the centerconsole. I get alittle shaft wipp on exceleration so I plan to upsize the shaft when I reprop.
     
  8. Steve H
    Joined: Aug 2004
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    Location: S.W. WashingtonState

    Steve H Senior Member

    I tried to use a dripless packing, but the shaft whip issue destroyed it in no time. Had to go back to standard stuffing boxes.

    Steve H
     
  9. tom kane
    Joined: Nov 2003
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    Location: Hamilton.New Zealand.

    tom kane Senior Member

    Shafts through the transom

    These S/P propellers with side plate rudders on Albert Hickman`s 20 ft Viper1V 6 cylinder 25 HP Ferro engine may appear to have water flow problems,the sea sled had a shallow V flatting at past midships through to the transom,and the sea sled gave good speed with the heavy machinery of the time.Power Boat Speed by Kevin Desmond.
     

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  10. Frosty

    Frosty Previous Member

    I bought a brand new cat and did just that I literally stuck 2 shafts out of the transom about 16 inches away, bought surface props 24x 24 and drove them with a pair of Yanmar 6 LPwith zf 630A down 8 degree gear boxes. My wieght is 14 tons and I can achieve 24 kts but cruise all day at 3000 RPM 16 kts. It is very smooth no vibration and use 45 liters per hour at 16 kts
     
  11. CaptPPan
    Joined: Oct 2003
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    Location: Bellport,N.Y.

    CaptPPan Junior Member

    Jack,
    Sounds like a nice boat, can you post some Pictures?
     
  12. Frosty

    Frosty Previous Member

    Hi Capt
    I new some one would ask me that hmmm i do have some but are of the boat when I bought her in aus. I know you want to see the drives. I am not very good at this, will get my buddy to help me --stand by - might take a day or two.
     
  13. Frosty

    Frosty Previous Member

    Ok I got to send you .Hope they come through. One is of the boat leaving Aus on a ship to Singapore. The other is just of the drive only. The rudder at that time was experimental. There has been three since then!!
     

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  14. CaptPPan
    Joined: Oct 2003
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    Location: Bellport,N.Y.

    CaptPPan Junior Member

    What a nice symple system. Is it comercialy availabel or did you make it up?
    Is there a conventional stuffing box on the inside of do you keep the water out some other way?
     

  15. Frosty

    Frosty Previous Member

    I made it myself. The shaft tube is a localy purchased shaft tube with a stuffing box on the inside but not what you would immagine, The stuffing box is another 12inches inside of the transom with a stainless steel threaded tub inbetween the two. Ille get my mate around again with the digital camera. The shaft is 4 foot in total length and is 2 inch dia. I changed the stuffing box for a deep sea seal that I had made up. Its just a bronze bush with with an oil seal at both ends and is supplyed with an oil supply this has been very succesfull. Before I did this I would blow out bits of greasy rope in an hour.I used to grease the shaft tube but now i dont so as to get water up the shaft and cool the seals wich could get very hot. I have pressure fed the shaft with sea water from a pick up at the side and drilled into the shaft tube. It might be a good idea to drill another nipple up at the top on the inside for water out ,then there would be an exchange of water. I might do that one day but up till now I have had no problems. Now if you want talk Rudders thats a different storey
     
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