Outboard Motor mounts other than transom

Discussion in 'Multihulls' started by Time2Tri, Jan 2, 2020.

  1. Time2Tri
    Joined: Jan 2017
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    Location: Madison CT USA

    Time2Tri Junior Member

    I own a Crowther 33 Buccaneer which has a stern mounted outboard and originally had a side mount of some sort located on the starboard side of the aft beam against the hull. The stern location is terrible in waves as the prop cavitation is problematic as well as the stern and amas clearly stern heavy. There is an access port from the interior at the nav station which is at the companion way. May be useful or not. Interested in sled design or other side mounts. Currently running a 4 stroke Yamaha 15 long manual tilt electric start so I’m headed to power trim and tilt if I have to return to a solid mount.
    thoughts appreciated.

    Central CT location - Steve
     
  2. oldmulti
    Joined: May 2019
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    oldmulti Senior Member

    I have a PDF of Crowther's 33 Bucaneer plan for an "inboard" outboard arrangement. Its over 12 meg therefore cannot be loaded here. I will see if I can "photocopy" it. Basically it cuts a 1 x 1 foot hole in the bottom of the hull for the outboard foot to go thru in front of the spade rudder. The sides of the hole are made from 9 mm plywood covered with 6 oz glass. Bulkhead 9 is revised and shifted forward 9 inches and made waterproof and has vertical slides placed on it that carry the outboard support bracket which is a combination of metal and solid wood that slides vertically. When the outboard is pulled up a plug is put in the 1 x 1 foot hole to provide a smooth hull surface. If its of interest please advise.
     
  3. oldmulti
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    oldmulti Senior Member

    Here is a "copy" of the Bucc 33 centre board, out board plan bottom of plan. Sorry about the size and lack of clarity. I will try to get a better version.
     

    Attached Files:

  4. catsketcher
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    catsketcher Senior Member

    Go the sled

    You can make your sled or pivoting nacelle to custom fit the boat. I have two rotating nacelles for my cat engines and they work really well.

    I am guessing but I would be thinking of a long pivoting nacelle/sled with its pivot near the back beam. If you can get some hinges there that would be strong. Then you have to make a plywood (I like ply for this situation as it is strong and puncture resistant) nacelle to fit the boat. Curve it if you can and make the bottom veed if possible.

    I would see if you can get away with not tilting the engine. Although you can let the engine tilt a little and then rotate the nacelle. That is what I did with my first rotating nacelle. You will need a hold down line for reverse though.

    For your boat you should follow what the guru did. Jim Brown made a beautiful nacelle for his Scrimshaw. Watch the video



    You can do the same with just a piece of alloy like they did on Spirit



    Learn from the clever guys - don't invent
     
  5. Time2Tri
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    Time2Tri Junior Member

    Old multi- My goal is to reduce weight aft so I’m thinking this isn’t going to work for me. Appreciate the thought and the centerboard layout is very interesting as I don’t have any sketches or drawings yet on my Buc.
     
  6. oldmulti
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    oldmulti Senior Member

    Look at page 7 and 8 plus a few other pages further on in the Multihull Structure Thoughts thread. You will find PDF's of the original Buccaneer 33 plans for the ply version and a round bilge version for foam glass hulls. The PDF's are spread over items as each are fairly large (up to 6 meg) and could not be posted in one group. If you have a good print shop you can get the plans printed full size or using appropriate PDF reader blow sections up to a readable size on screen. Have fun.
     
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  7. cavalier mk2
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    cavalier mk2 Senior Member

    I agree with Phil about sleds except for one small point. I love the one I did for my boat which does manage to retract an extra long shaft without kicking it up. The small point is you do have to be inventive to make a sled work for your particular boat depending on the layout and construction. Make the attachment area reinforced to handle the lever arm loads of over 100 pounds bouncing around in a seaway.
     
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  8. Time2Tri
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    Time2Tri Junior Member

    Sled is definitely the way to go now that I’ve had a look at my boat again today. While I still need to build it and I’d love some plans to work from some advice from this forum would be wonderful. I’m uploading some pictures so you will understand that my boat has this cutout on the starboard side which the raised engine head will slide right into thereby hiding the unsightly thing quite well while providing access to the head if needed but also an Easy way for me to access the manual trim tilt handle thereby eliminating the need for me to buy a power tilt motor as I already own a good running 15 Yamaha electric start. 8D52C5F0-2A18-488F-8D98-4B8F318538F2.jpeg 17CF12D7-7BFA-42A4-9823-05F98CE0EA81.jpeg 0AB6455F-D19C-494D-BF47-BC6599169012.jpeg 20409CD1-C720-4FB8-912D-7EE1AF35A596.jpeg 8D016C70-679C-4514-8314-E65A93C8179B.jpeg
     
  9. cavalier mk2
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    cavalier mk2 Senior Member

    Useful aperture. I put one in my Nicol quarterdeck for the motor when retracted and had the arms stretch up to the rear wing bulkhead which I beefed up to handle the loads from the pivot extensions which tie into that aka. My sled is a bit different as the sled has room to retract into the quarter deck structure but the arms run against the wing bottom for a ways to preserve a walkway/wing support structure that is necessary for that boat.
     

    Attached Files:

    Last edited: Jan 6, 2020
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  10. Time2Tri
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    Time2Tri Junior Member

    Looks terrific and solid too. What did you use for materials? Is it waterproof per se?
     
  11. cavalier mk2
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    cavalier mk2 Senior Member

    The arms are laminated of cvg fir in thin layers. The sled hull and deck is about 1/4" bs1088 meranti ply, back where the motor bolts on is built up out of marine fir ply. All epoxy coated and covered in dynel for abrasion resistance with biax glass used in reinforce areas and carbon fiber on the ends. For the pivot bolt areas oversize holes are drilled and then filled with epoxy with filler/thickener. Once dry that is drilled for the pivot bolts giving a hardened bearing far away from the wood laminate to prevent water intrusion.

    It is light, but strong where it needs to be.

    Lots of different ways to do these things but I like playing with wood composites.
     
    Last edited: Jan 7, 2020
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  12. Time2Tri
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    Time2Tri Junior Member

    Beautiful result. Mine won’t be as pretty but functionally sound and light without exotics....
     
  13. cavalier mk2
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    cavalier mk2 Senior Member

    Looks much plainer installed as it is painted white to match the hull. This sled was designed to work with the limited space between the quarter deck frames I was keeping. Every design is going to have different compromises to make so there isn't a once size fits all when it comes to sleds.

    My advice is to download the plans old multi posted or make a drawing to scale of your area and the waterline and make silhouette mock ups of the sled to get the layout right for your shaft retraction and the sled transom angled right for the motor when in the down position. Use a pin for the pivot and scale a profile of the motor to go on it and start trying things till you get what is the best compromise.

    You want a fine entry on the sled to minimize slaps, mine runs just above the surface, the deck lip keeps spray from waves off the motor.
     
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  14. Time2Tri
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    Time2Tri Junior Member

    Great advice. I’m on it. Found a design which looks a lot like the searunner design but realizing every boat is different so your idea makes a lot of sense. Be in touch with progress.
     
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