Catamaran Single Engine One Hull

Discussion in 'Multihulls' started by Boatguy30, Jul 20, 2012.

  1. Boatguy30
    Joined: Dec 2011
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    Location: St Augustine, FL

    Boatguy30 Senior Member

    Pics

    Phil-

    some pics would be great. I assume the motor you have is a 20" shaft? the Yamaha 25 is not available in the US as a 25".

    I had originally planned to use a swinging bracket on my Woods Vardo, but Richard will likely draw a fixed one like on Eclipse and Romany. In lite trim my cockpit will be 28" above the waterline so I think anything fixed, especially for a 20" shaft would be a major drag and hard to get to the motor.

    there is a company in the US making 5" extension kits for most motors. Perhaps there would be a good market for these in Australia?

    did you write an article about adding a bridge deck cabin to your cat? If so I may know your brother Jamie.

    Cheers,
    Jeff
     
  2. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    The Yammie I have is a long shaft - 25 inch called a big foot. Works well but can be a little rough at some revs. Friends had the same engine (Merc 25 big foot is same) with the 5 inch extension. Due to harmonics in the shaft the driveshaft ate out the spline in the crank and there was an awful amount of angst and money spent. They got rid of the extension and went back to a 25 inch.

    cheers

    Phil
     
  3. Boatguy30
    Joined: Dec 2011
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    Location: St Augustine, FL

    Boatguy30 Senior Member

    motors

    I'm sure there are some potential issues with the aftermarket extensions. Not aware of any markets with the Yamaha and Mercurys the same engine and have worked as outboard mechanic in NZ.

    Anyhow, if you can post some pics of your setup that would be great.
     
  4. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    Kankama video

    Gday

    I went out and took a very bad video of Kankama's pivoting nacelle. You have to put your head on its side as I held the camera wrong but it should give a broad brush of my approach.

    http://youtu.be/KAIsMz-2jVA

    cheers

    Phil
     
  5. Boatguy30
    Joined: Dec 2011
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    Location: St Augustine, FL

    Boatguy30 Senior Member

    Great Cat

    Phil-

    that's a great looking boat! Wow, that box has to be big but I guess doubles a good place to stand to see over the cuddy. I think the centerline wheel makes good sense. Is it cables to quadrants?

    Cheers,
    Jeff
     
  6. Eliseviv
    Joined: Jan 2011
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    Location: Darwin

    Eliseviv Junior Member

    Thanks Phil.

    Good Looking boat. Also had a look at your tour in another Vid :)

    I can make that nacelle arrangement work, so thanks for the idea. When the nacelle was down does it need locking off?

    Thanks

    Brett
     
  7. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    No Brett - no locking required for full throttle reverse. What I did not include in the vid is the hinge. It is just a stainless tube glued and stitched with uni to hold it in place. I love stitching with uni as it is really strong. Make the ears strong as well. Glass them till you get tired.

    cheers

    Phil
     
  8. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    The box

    Jeff - the box is wide because of the size of the motor. It fits in well in the cockpit still. It is our seat and we can stand on it when mooring etc. As we often use autopilot the seat does not have to be too comfortable and it is better for me not to have a cushioned driving seat that would get in the way during manouvres. I had a bigger seat before with a back and got rid of it.

    Steering is vectran line to the tiller link bar.
     
  9. Boatguy30
    Joined: Dec 2011
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    Location: St Augustine, FL

    Boatguy30 Senior Member

    Phil-

    By stitching do you mean there are slots in the in the bridgedeck that the uni tape laces thru like a webbing buckle?

    You're dead right on the autopilot. I never hand steer when cruising especially with kids!

    What kind of fuel burn to you have at cruising speed? I'm planning a 15 or 20 hp for my 34' cat.

    Jeff
    sailingcatamarans.blogspot.com
     
  10. catsketcher
    Joined: Mar 2006
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    Location: Australia

    catsketcher Senior Member

    Gday Jeff

    With stitching I mean you drill some 5 mm holes next to each other and staggered as if you were going to tie the thing on - like shoe laces. Then I get some strands - I rip off the end of 600gm biax - about 8 strands about 1 metre long. I wet them out and then pull them through the holes just like I am tying it all together. Put as much tow through the holes as you can. Shove some filler in the holes when wet and then whilst still wet get some double bias and go over the lot - Pull tight as you go. Really cheap and easy and best of all strong.

    My genoa blocks and Catspaws sidestays are shackles held in place with tow. My genoa tracks are stitched into the cabin with tow and are lovely and leak free, quiet, cheap and worry free. The motor hinge is stitched and it is how I am building the hinges on my folding cat.

    With modern composites you should try and stitch all you can. Get rid of the stainless fittings and make it out of glass.

    cheers
    Phil
     
  11. keysdisease
    Joined: Mar 2006
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    Location: South Florida USA

    keysdisease Senior Member

    An I/O leg on a Prout and a hinged "sled" on a Gold Coast Cat. I think the sled arrangement to be the simplest, most flexible and easiest to use of all the adjustable methods.

    Steve
     

    Attached Files:

  12. delebash
    Joined: Aug 2012
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    Location: Eastern Shore of Virginia

    delebash New Member

    I had a macgregor 36 with a 25 hp on one hull.

    It was connected to the opposite tiller by a long tube so that the motor turned with the rudders. This was very satisfactory. I could kick the stern either way. It was on a sliding bracket with a 4 to 1 purchase that could lead to a winch solely for the engine. Depending on the tack, you could adjust the height of the engine. A few times it doused itself pitching but it fired right up. I could do 8.3 knots by GPS in a calm. A modern 4-stroke or fuel injected 2-stroke would be a pretty impressive but inexpensive set-up. Of course, if you are building, your options are many with a smaller difference in expense. Building a pivoting sled would have been more difficult on this tramp type cat.
    By the way, it only had one daggerboard and that was also satisfactory.
     
  13. Stefan Gessinger
    Joined: Jan 2021
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    Location: Canada

    Stefan Gessinger New Member

     

  14. Stefan Gessinger
    Joined: Jan 2021
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    Location: Canada

    Stefan Gessinger New Member

    Hi Phil - I came across your description of stitching genoa tracks, folding catamaran hinges and general joinery with 600 g biax strands and am hoping to pick your brain on your catamaran hinges (I am intending to build the non-structural hinges for my 24' folding catamaran in fiberglass). stefangessinger@gmail.com
     
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