alternative to driveline stuffing box

Discussion in 'Propulsion' started by need-help, Mar 23, 2006.

  1. need-help
    Joined: Jan 2006
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    Location: new jersey

    need-help Junior Member

    Are there any other options to pass a drive shaft thru the hull?
    The Drive is a 5hp electric motor, and I really dont want the headache and maintenance of a conventional stuffing box.
    Are there any other alternatives? Like a stuffing box with bearings? and sealed with grease or oil?
    thanks for any help or guidance
     
  2. SeaSpark
    Joined: Mar 2006
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    Location: Holland

    SeaSpark -

    water lubricated rubber bearing

    By far the most easy way to seal a shaft in this power range is a water lubricated rubber bearing.

    It's a seal and bearing in one, we own a boat with a 6hp engine for 28 years with a rubber bearing, now problems so far. The bearing is lubricated with water from outside the boat beeing sucked in via a small groove in the rubber (does not go all trough).

    the first supplier google came up with:

    http://www.yardeng.com/productwriteup.asp?id=11

    good luck with your project, diesel engines are old fashion.
     
  3. need-help
    Joined: Jan 2006
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    Location: new jersey

    need-help Junior Member

    seaspark...
    im a little confused. The bearing support for the prop shaft going thru the hull (transom) will have a bearing support on each side. The exterior (wet side) will have the bearing inside of the stern tube and this will be lubricated by the surrounding water.
    Now on the inside of the boat.. where will the water come from to lubricate the bearings/seals? and where it will it go?

    I was hoping there was something available similiar to the lower unit of an outdrive/outboard (with just a single shaft passing thru it). Something that would have bearings in a housing with grease inside of it - then could be bolted up to the exterior of the transom as a complete assembly - the input side of the shaft would then protrude thru the hull to the inside. The housing would be bolted and sealed to the transom like an outdrive.

    Compared to the simplicity of the stuffing box, certainly making this harder - but im still confused on the how the inner bearing surface of what you suggested works and how it is lubricated and sealed.
     
  4. SeaSpark
    Joined: Mar 2006
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    Location: Holland

    SeaSpark -

    water lubrication

    For an example look at:

    http://www.vetus.nl/indexns.asp?lang=2&productid=14

    (vetus.com and www.vetusmarine.com for US also exist but seem to be down, site content is the same.

    Here water is provided by tapping a small amout of water from the engine's cooling water, you don't have, or by a water scoop in the hull.

    The sytem on our boat seems to be out of fashion.
     
  5. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    As long as your installation is done correctly, you should not have any problem with traditional stuffing box/water lubed bearings, especially if you choose one of the new "dripless" packing materials. While the initial cost of the packing is rather astonishing ($65 @ West Marine) for a pill bottle of it, the payback is truly "dripless" shaft sealing. Just be careful when installling it, as the old method of adjustment doesnt work. You must install it loosely, then launch the boat and tighten it SLOWLY over a period of days until it doesnt drip. Also very important to use the proper grease as specified by the packing. With your low hp and smooth electric power, it sould last a long time.
     

  6. Proper
    Joined: Mar 2009
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    Location: Seattle

    Proper New Member

    I like the shaftseal.

    Just adding this for posterity's sake: PYI has a PSS Shaftseal that's pretty good way to go for a drip-less operation that's a good alternative to using a stuffing box. You can see how they install here:
    http://www.shaftseal.com/about/installation_videos
     
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