Motor Mount Pics Please

Discussion in 'Multihulls' started by ThomD, Dec 23, 2017.

  1. ThomD
    Joined: Mar 2009
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    ThomD Senior Member

    I have had trouble with my various motor mounts over the years, though they are relatively simple things, so changes are no big deal. I want to put a motor on my 24' trimaran, so pics from boats of that size are what I am after. However, please add any mounts you have pictures of that you think there might be interest in.
     
  2. gonzo
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    gonzo Senior Member

    Inboard engines come with mounts. Is this an application where the standard setup won't work? In general mounts last for several thousand hours of operation; particularly in small engines like your are referring to. If they are failing it is almost surely an installation problem. Misalignment is a common cause of failure.
     
  3. ThomD
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    ThomD Senior Member

    I'm thinking outboard motor mounts. There is no normal, just a square marked 4 hp off the back of the boat which is 3/8" plywood.
     
  4. gonzo
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    gonzo Senior Member

  5. Corley
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    Corley epoxy coated

    Hi Thom, This is how Jason Gard did the outboard mount on the 40' trimaran Spirit. I'm going to do something similar of course appropriately scaled down on the 23' Tremolino trimaran. The simplicity appeals and apparently it works well. IMG_1806.JPG IMG_1807.JPG IMG_1811.JPG IMG_1813.JPG
     

    Attached Files:

  6. jamez
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    jamez Senior Member

    Here's mine. 25 foot tri, 5 Hp at the time. Bracket has since been upgraded to suit a bigger motor, but it still mounts in the same place. DSCF1085.JPG
     
  7. ThomD
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    ThomD Senior Member

    Thanks for those pics!

    Jamez, I think that may be what Kurt had in mind. I was surprised to see when I looked into those that at least the ones I had available were listed as not suitable for 4 stroke. I bought a 4 stroke online, but it really seems too heavy in general, so I am again looking for a 2 stroke, I had one that was stolen.
     
  8. jamez
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    jamez Senior Member

    The Hughes 23 that used to be in Auckland had a similar setup (rise and fall bracket), mounted of the port rear of the cockpit pod.
     
  9. jamez
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    jamez Senior Member

    Thought I had a pic of it somewhere......

    H23  ob bracket.jpg
    P1050246.JPG
     
  10. bruceb
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    bruceb Senior Member

    Hi guys, I am still around, and of course, I do have an opinion. I also have tried to design/build a "better" mount. Tried! I am quite the expert on what didn't work very well. The mounts that hang too low tend to drag in waves, particularly on the smaller tris. On the bucs that tend to drag their sterns, any mount that doesn't lift the engine mounting board fairly high is a problem. Also, outboards work much better with a planing surface at about the cavitation plate height in front of the engine.
    I think a modified version the the production lift mount with a hinged board added in front of it might work well for our boats.
    Bruce
     
  11. Corley
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    Corley epoxy coated

    Have you heard anything more on Creepy? I had a chat to the new owner at one stage it sounded like a thorough rebuild was on the cards. I have the plans and was hoping to return them to him when it was convenient.
     
  12. jamez
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    jamez Senior Member

    Hi Corley, haven't heard anything recently. I'll have an ask around. Alternatively you could try posting on Crew.org.nz's 8.5 page.
     
    Corley likes this.
  13. ThomD
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    ThomD Senior Member

    I guess that is what is intended on my boat. I used to have a 3.5 2 stroke, and it was stolen. But the new 4 is a heavy lump. Then I read the Tohatsu 4HPs aren't really 4 strokes, they are something else which explains why they are so loud and vibrate a lot. Overall, I don't think it will work over the back like that, though I am not against getting another motor, I have also been getting into flats skiffs a lot lately, and they use a lot of upsy downsy things on their motors, a lot more sturdy than the standard bracket not in all cases heavy as extreme light weight is a factor.

    I am pretty depressed about the process so far.

    Actually I am normally more of a limited purpose action hero than this story makes me out to be, and the complete waterman, BUT... I also got hosed on this stand up paddle I bought to paddle the boat. It worked really well but with a stack of under 10s in the boat, something happened, and rather than pull the paddle up around all the lines, and booms, and beams and stuff, I just let it drop, and attended to whatever neglected nose wiping was going unattended. It was the right thing to do since I could go back and pick up the paddle, cause you know they float... Dove all over the place, never located it.

    Actually reminds me of the time the engine fell off the back of my motor mount on this motor cat I built and augured itself underwater. Now that one I was able to find. But it is amazing how much sea bottom there is to cover even when you immediately mark the spot you parted company with the motor.
     
  14. ThomD
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    ThomD Senior Member

    Jamez, do you have up close pics of that rudder, looks like an interesting installation.

    OK, I think I am seeing it now, there is a top bracket I didn't notice at first. Is the blade in a slot like a daggerboard?
     

  15. jamez
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    jamez Senior Member

    Yes, its a simple dagger rudder, quite a common setup over here.
    The motor mount worked fine. Although its been taken off for racing here, the boat at this time (2009) had a 3.3 Tohatsu 2S (later upgraded to an 8hp Yamaha 2S). Both these engines were long shaft versions, essential to keep the prop in the water as much as possible. Small 2 stroke outboards are still freely available here.

    P1050246.JPG
     
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