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Jet pump on 42 sailboat - anybody knows if it would work?

Discussion in 'Technical Discussion' started by morten, Feb 25, 2007.

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  1. morten, Feb 25, 2007
    #1
    morten

    morten New Member

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    Was woundering if a setup with a jet pump of some sort and 4 exits ("corner direction") would work on a 42 feet sailboat - a independent system from the inboard engine that could assist when docking.

    Which kind of jet pump or impeller would be the best solution - would it work with an electrical engine running from the boats battery setup?

    What would this system weigh and cost (not including the mounting)

    Hope somebody out there has a few anwsers
    /Morten
  2. AMG, Feb 25, 2007
    #2
    AMG

    AMG YF Moderator

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    Hi Morten,

    I saw what you are describing in a magazine the other day, but now I can´t find it again...

    However, there have been similar setups in the past, and a normal prop thruster is probably more effective. If you are afraid of missing speed under sail, you can have a retractable. There are even retractable and steerable thrusters if you like.

    Normally you just need them in windy or tide situations and one (electric) bow thruster of 5-8 kW will be enough. Weight is 20-30 kg and a fixed tunnel would be 140-180 mm. Price 15-25´SEK.

    If I´ll find this jet thruster again, I´ll post it here.
  3. morten, Feb 25, 2007
    #3
    morten

    morten New Member

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    Total independent system?

    Thanks for reply - I was thinking of a system where you would not use the inboard engine at all. I mean if you have 4 exits pointing at the boat "corners" then you would be able to use it without the normal prop.

    Maybe with one water inlet and one jet which is distributed out in 4 channels with electrical hatches - in this way you can control the boat in all directions independent of the prop and rudder.

    Is this possible and which jet size would be necessary for a 42 feet 9 ton sailboat?
  4. morten, Feb 25, 2007
    #4
    morten

    morten New Member

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    retractable and steerable thrusters?

    You mention: "There are even retractable and steerable thrusters if you like" - but i did not seem to find any for this size of vessel - 42 feet sailboat.

    Is it the azimuth typ you refer to?
  5. AMG, Feb 25, 2007
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    AMG

    AMG YF Moderator

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  6. AMG, Feb 27, 2007
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    AMG

    AMG YF Moderator

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  7. Brumberty, Feb 27, 2007
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    Brumberty

    Brumberty New Member

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    I drove an antarctic loading barge with 4 hamilton jets, two on the transom with reverses and a hydraulic one on each bow (reversable too)

    It was a forest of levers!
    It could turn or crab any direction.
  8. Norseman, Feb 28, 2007
    #8
    Norseman

    Norseman Senior Member

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    Hmm ,never heard of this on any kind of a sailboat.

    The mechanics and plumbing may cost more than it is worth?
    Not that hard to dock a 42' sailboat.
    If ya have to dock in a gale call ahead on the radio and have several people meet ya on the dock to catch the lines.

    If that ain't gone happen, go around the corner and drop anchor 'till stuff settles down, with a beer in hand.

    Sure, ya could make a 40 something sailboat fly if you installed retractable wings and a big enough powerplant, but, uh, we sailors like to stay low-tech and go for the piece and quiet and the pretty sun-sets.
    Let the power boaters install the high tech stuff to drool over in air conditioned comfort while watching their plasma TVs tied safely to the dock with the blender going full speed mixing the gin to feed the palace...:D :D :D
  9. tri - star, Mar 5, 2007
    #9
    tri - star

    tri - star New Member

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    To Jet - or not to Jet

    To morten:
    Where you live, they make some of the biggest and best jet drives - anywhere. So a few local calls,
    I'm sure will be productive.
    Personaly, I like jets.
    However, most effective units, on the market,
    are designed to work best, at over 30 knots.
    Especialy, in the smaller sizes.
    And they do not like going slow....

    Although, as Bruberty indicates: in the commercial sector you will find industrial strength
    - High Thrust.... Low Speed - jet drives.

    Your requirements, run counter to all these trends.
    That is: You need light duty, small unit(s).
    That deliver high thrust - at relatively slow speeds.

    So...yes. It can be done. What you describe exsists.
    It's done on a larger scale. Every day.
    However, is it cost / effective, in your situation. ?
    Certainly will not be as easy to fix - when things go wrong.
    As other options, presently are.

    'Regards !