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Retractable Marine Drives

Discussion in 'Technical Discussion' started by brian eiland, Aug 4, 2016.

  1. brian eiland

    brian eiland Senior Member

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    Many sailors would like to have a 'retractable propulsion system' to eliminate that excessive drag of conventional 'fixed' prop/shaft systems. There have been a number of different systems worked on in the past few years, but mostly custom systems that have not reached any production status.

    I even suggested one utilizing a 'rim drive propulsion unit' ,
    http://www.runningtideyachts.com/dyn...Rim_Drives.php

    .....but development efforts on these rim drive units dropped off significantly during the depressed yachting market following 2008.
    Just to clarify, there is a distinction between the '(bow)thruster units, verses the propulsion units. The thruster market has progressed along, but little work has been put into the propulsion units.

    I was just doing a little research on retractable propulsion units and ran across this mention:
    http://www.shippingandmarine.co.uk/a...39&issueid=454
    Anyone know where we might find some photos and more details on these units?
    Last edited: Aug 4, 2016
  2. K1W1

    K1W1 Senior Member

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    Schottel were willing to build us a pair of azumithing retractable rim drives each of around 600 ekW a few years ago so info must be out there.
  3. brian eiland

    brian eiland Senior Member

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    As you say there are some custom units out there, its just tough to find out about them in any detail as they are so 'one-off'

    The reason I found that reference above to the Ocean Yachts System unit was thru a google IMAGES search for 'retractable marine drives'. Sometimes its amazing where google IMAGES can take you.
  4. CptnMaxwell

    CptnMaxwell New Member

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    Have a look at the high-end sail yacht builders as they are all trying it at the moment.
    Vitters
    I think both Baltic and Nautors-Swan have both been working on it also.

    Its a very interesting trade-off for these vessels. Reduced drag while sailing versus a significant weight penalty (although in a reasonable location). One big advantage is the allowance for two drives that are not reliant on rudder for steering giving independence of sailing control and motoring control - less compromises in either mode. With the increase manoeuvrability there is possibly no need for a bow thruster, reducing weight forward.
  5. brian eiland

    brian eiland Senior Member

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    Thanks for that info.
    They don't address any details as to how the power gets transferred from the engine to the propeller unit. This might be particularly interesting in that the prop unit can rotate around its vertical axis under power.

    I did just find this statement on this page:
    http://www.vitters.com/unfurled/#unfurled
    They refer to them as 'thrusters' rather than propulsion units?
    And they say they are direct drive??


    Hydraulic Steering Feedback System
    I also found the hydraulic feedback system of there's very interesting as well
    Last edited: Aug 4, 2016
  6. brian eiland

    brian eiland Senior Member

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    BTW I just received an answer from OceanYachtSystems that their units were:, " Hydraulic in deployment, rotation and propulsion."
  7. brian eiland

    brian eiland Senior Member

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    I thought my concept incorporated a minimum use of space, ....particularly if you viewed it from a profile view:
    [​IMG]
    [​IMG]

    ....of course that was if they could produce a reasonable size rim drive PROPULSION unit
  8. brian eiland

    brian eiland Senior Member

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    Piston Boxes for Retractable Rim Drive
    BTW, the tops of those 'piston boxes' that housed the rim drive units were above the load waterline of the vessel, so the rim drive units might be extracted from the vessel for servicing even while the vessel was still afloat in the water.
    Attached Thumbnails
    [​IMG] [​IMG] [​IMG]
  9. Wouter SMG

    Wouter SMG New Member

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    Hi Brian, take a look on our website, ship motion group, we have a standard solution for the superyacht market.
  10. GhostriderIII

    GhostriderIII Member

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    Very interesting Brian. I like your ideas. My next sailboat will have retractable (up-down) engines. I just haven't decided how we will proceed.
  11. brian eiland

    brian eiland Senior Member

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