I/O to outboard

Discussion in 'Boat Design' started by Rranger, Nov 26, 2020.

  1. ondarvr
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    ondarvr Senior Member

    The correct flotation bracket on a conversation is typically larger and displaces more water to keep the boat level at rest. Plus adds running surface area back further, more like a normal hull. The added running surface is where the potential for a better ride comes from.

    In a new build its accounted for in the design and a bracket alone may be sufficient. But can go either way.

    You gain space in a conversation, whether going from an IO or OB. You still need to fish around the motors though. Taxes and registration continue on based on the original length.

    In a new build it depends on exactly how they build it for tax and registration purposes. They also frequently fudge on the length, so you think you're getting more boat for the money.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Your typical pod is not in contact with the water at speed, sure you get a greater lever arm for trim purposes, but they are a mixed blessing, depending on the hull.
     
  3. ondarvr
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    ondarvr Senior Member

    A pod can be used both flush with the bottom, or raised up slightly as a step. The other style slopes up slightly and is out of the water at speed.

    As you said, your leverage is greater with the pod out of the water, that's why newer builds go that route. Conversations frequently need the extra running surface to deal with porpoising.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    I have seen some excellent power cats at the smaller end of the range, ruined by pods, turned them into turkeys, it really is not a panacea, but the demand for more internal space is even greater in smaller boats, which is what more or less forces their use.
     
  5. brendan gardam
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    brendan gardam Senior Member

    that pride runabout in my 1st pic goes well except for the poirposing at speed.
    the larger boat in the second pic goes well but too bouyant at rest. chines are above the water. i am going to leave the bung and hatch off next time to see if filling the pod with water helps.
    we fitted a hull extension pod to my cousins 18 ft mustang which was originally an outboard well. that boat had a destinct improvement in ride with the longer waterline.
    i also converted an 18 ft hartley from vdrive to outboard pod and that boat performed great with an old johnson 115 on it. sat on its lines too.
     
  6. Rranger
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    Rranger Junior Member

    Well I’m pretty much convinced to go transom mount and splashwell. I did it once before. I have 1/2 “ and 3/8” plywood already installed and still good. Was going to add two sheets of 3/4” but the transom has a curve to it and after roughing the first 3/4” in I’m not sure about the 1” gap at the top of the transom. I know I can screw it down while curing but I think 3 half inch sheets might work better. Less stress I’m guessing on the bend at the top. It’s a nice big boat and a splashwell won’t take up that much room. My progress in the photo’s.
     
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  7. Rranger
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    Rranger Junior Member

    Photos
     

    Attached Files:

  8. gonzo
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    gonzo Senior Member

  9. Rranger
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    Rranger Junior Member

    Yes something like that saves buying a bracket.
     
  10. brendan gardam
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    brendan gardam Senior Member

    I think that's a good idea. Looking forward to seeing the finished photos.
     
  11. Rranger
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    Rranger Junior Member

    5F240821-65DC-4822-BBEF-A427CA94BE14.jpeg F7DDBC54-09FA-4F35-9D36-4594A149141A.jpeg 0B45E31D-0050-4E55-B622-9B98569C96DD.jpeg

    Yesterday I got the piece glassed up against the old outer fibreglass skin from the inside and a layer of cloth and glass on the outside. Today filled all gaps around the inside edge’s with short strand bondo top part will be below the cut line so didn’t bother filling. . Also have to sand down the white part of the outside patch get rid of the air before the next patch. And fillin the bottom of the outside.
     
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  12. Rranger
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    Rranger Junior Member

    Ready to put on my first sheet of 3/4” full transom size. Question is a coat of resin on both pieces. Let it dry? Do it all while still wet? Or it don’t matter? While wet I can stick my mat on the unwaxed transom side soak it with resin Then soak down the mat side, then apply peanut butter on loose piece and install.
     
  13. Rranger
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    Rranger Junior Member

    The two sheets of three quarter inch plywood glassed in. Do the edge tomorrow with peanut butter then ready to encapsulate. But a question. I’m going to build a splashwell so part of its pieces will act as full height knee braces for the transom and also I need to attach a couple knee braces to the stringers and beef them up at the connection point. I’m thinking I should do that first then encapsulate the knee braces to the bare wood of the transom at the same time as I encapsulate the transom. Or do I encapsulate the transom first then attach the kneebraces to the new fibreglass on the transom? Or does it matter lol.
     
  14. ondarvr
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    ondarvr Senior Member

    Do the transom first, no wood to wood contact of different components.

    With a splash well the need for knee braces is significantly reduced, normally they aren't added to boats with this type of build. It's OK to add them, but it's valuable space under there.
     

  15. Rranger
    Joined: May 2013
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    Rranger Junior Member

    Thanks Ondarvr appreciate the reply, didn’t know about no wood to wood contact of different components. I’m hanging a 125hp merc so I’m nervous about strong enough. Going to build in a way hopefully storage won’t be compromised.
     
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