seafury drives

Discussion in 'Surface Drives' started by mobydick, Feb 12, 2009.

  1. mobydick
    Joined: Jan 2009
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    Location: Ireland

    mobydick New Member

    hi all

    I am looking at putting twin diesels around 350 to 400 hp in a 10m rib, what do ye think of seafury surface drives?
    thanks phillip
     
  2. Frosty

    Frosty Previous Member

    Seafury are Ok if you need an agricutural sytem that you wish to antifoul and leave in the sea. May not be the case with a RIB.

    They are heavy too.
     
  3. mobydick
    Joined: Jan 2009
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    mobydick New Member

    too heavy

    witch other surface drive would you sugest ? I like the shape of the seafury and the 45 deg transome idea. I am doing a few endurance record attempts soon, I want to move away from petrol to diesel and I am not gone on the bravo legs the boat will start in June.thank you
    Phillip
     
  4. xrudi
    Joined: Jul 2003
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    Location: Philippines

    xrudi Rudi Scholz

    LeviDrives Side Winder

    Maybe our LD SD 280-300 would be the right drive for you. A 45 degree transon is required. We have also a new propeller (see photo gallery).

    Rudi
    Levidrives
     

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    Last edited: Feb 14, 2009
  5. mobydick
    Joined: Jan 2009
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    mobydick New Member

    levidrives

    sent email through your website ,would there be extra drag with the two rudders in the water?
    regards Phillip
     
  6. Jarrod
    Joined: Jul 2004
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    Location: New Zealand

    Jarrod Marine Designer

    Dear Phillip,

    I would highly recommend the Seafury drives. Well designed & manufactured, with a long track record.
     
  7. Frosty

    Frosty Previous Member

    Twin tunnel rudders= 4 rudders in total there is drag and alignment probs. The Flexitab drive which looks just like the levi drive has only one rudder. They have simply cut one side off.

    I have recently bit the bullet and done this to my 2 tunnel rudders. Cut one off and increased the aspect ratio of the remaining rudder It put 3 knots on the top and corners much much better.

    Power cat 2x250HP 14 tons 44 foot.

    The drives are nothing, they simply hold the prop in the right place.

    Whilst I use the Seafury props which are the sonny Levi diamond backs, I have experimented with rudders behind the surface prop. I eliminated vibration by not doing so.

    Surface props by thier nature potrude a long way out of the back, having to attach a rudder as well makes it difficult.

    For a twin drive boat rudders do not need to be behind the props.
     
  8. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    Frosty,

    Do you have some pics and performance data on your boat. I am trying to do similar and slowly achieving it. Rudders are a problem- went all over on them. Even thinking of a single rudder in middle of boat leaving propellers completely clean. Are your rudders offset of shaft or completely outboard
    thanks
     

  9. Frosty

    Frosty Previous Member

    Here is one of the best surface prop threads.

    There is a picy of my rudders but those rudders were modified years ago. Same place though.

    http://www.boatdesign.net/forums/powerboats/shafts-thru-transom-2155-8.html

    With bulbous bows it is my thoughts that I get a bit of bow steer, it is for this reason I am keeping on the "larger" rudder idea.

    Aspect ratio (deeper) is very performance enhancing.

    Try to google up the Atlantic Challenger her rudders are forward and of course to the side of the props on the hulls. However this boat was made to do one job only and steering was'nt really one of them.


    This is the Flexitab http://www.flexitab.com/eng_flexiboat.html

    I have copied this one legged approach and adopted the removable rudder blade. I have also gone for the wedge rudder which I should have done years ago instead of messing with a foil shape.

    I am 2x250 HP Yanmar 6LP. Hurth A 630 gearboxes with down 8 degrees max RPM 4200 ,-2 inch shaft of cutlass bearings fed from exhaust feed. 24 x 24 x 4 blade Nibral diamond back by Seafury.

    3400 RPM is 20.2 knots (GPS) 35 liters per hour ( both )
     
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