Couple ?s on inboard/outboard conversion to outboard bracket

Discussion in 'Boat Design' started by the brain, Nov 28, 2016.

  1. the brain
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    the brain Senior Member

    Couple ?s on inboard/outboard conversion to outboard bracket
    I have a older Armstronge stainless steel (late 80s bracket I refer to as a POD)

    It started as a 29” POD I reduced it to 18” (did’nt want alot of setback engine interfering w/ fishing and increasing the water level) but did need enough setback to route control cables,steering tubes, fuel/oil lines, engine harness ect.

    Where the bottom part of POD contacts the transome there is a ¼” opening I believe this opening was designed to drain saltwater from inside the POD to prevent rot however it also fills the POD halfway w/ water.
    ?1.is the POD designed to be filled w/ floation to minimize how much water can be inside POD? I currently don’t have any floation inside POD.

    The backplate where the engine is bolted to the POD has two sets of holes I’m using the upper set so water was filling POD though the bottom set of holes if I bolted the engine to the bottom set of hole water would come though the top set of holes so I sealed the bottom set of holes.
    All this doesn’t make much sense Armstronge built a POD designed to take on water from front and back?

    I have more ?s just starting of w/ 1
    Thanks STB
     

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  2. the brain
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    the brain Senior Member

    anyone w/ advice on POD
     
  3. PAR
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    PAR Yacht Designer/Builder

    Yep, the pod is supposed to fill with water and the gap against the transom is to permit it to drain out. You could put a scupper on the gap, which will cut down on how much water it does hold, but so would a much bigger gap or holes too. I'd put 4 good size holes in the bottom plate, say 2", with two out back and two near the front. Odds are the bottom of the bracket is running clear, with just some splashing getting in, while up on plane. The bulk of the water likely is driven in through the little slot, in the hole shot, as you power up to full plane. If this can be controled, say with a flap or big holes to prevent accumulation, you're good to go. That looks to be about 2 cubic feet of volume, so you'll save a fair bit of weight, with an empty bracket.
     
  4. the brain
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    the brain Senior Member

    OK I'll be checking into a scupper, diffientley a few drain holes, or should I remove the angle piece I glued to the bottom front of POD sealing it? see attached image.

    yes I don't want the added weight of the water filled POD it is contributing in addition to water inside bilge to porposing.

    from what I understand proposing is caused by stern being to heavey.

    what do you think of filling the POD w/ floatation to minimize how much water can be held in POD? like if floatation is in the inside of POD it will occupie the space the water would usalley be?

    also will the floatation inside POD raise the water level?

    Thanks STB
     

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  5. PAR
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    PAR Yacht Designer/Builder

    Filling with foam is an option, though it'll probably eventually get saturated. I'd cut holes between the stitch welds, which appear to also be intended to let it drain. It's going to get water in it, the idea I think is to also let it get out quickly.
     

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  6. the brain
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    the brain Senior Member

    look at the side view notice how the front is much lower than the back of POD I think the orginale 1/4" opening in the front of POD is enough of a opening for drainage.

    the welded seam isn't designed for drainage because it's completely welded.

    I will definitely add some smallish holes in the front of POD where I sealed it.

    as for floation I was thinking of having heavey duty plastic bag inside POD then use poured in foam is this stuff a imitation poured in foam?

    http://www.homedepot.com/p/GREAT-ST...acks-Insulating-Foam-Sealant-162848/100003351

    I'm also concidering cutting up a old cooler and stuffing the POD.
    thanks STB
     
  7. Ike
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    Ike Senior Member

    I would definitely not put foam in. This is stainless steel. Stainless will corrode if kept wet. Water will get trapped between the foam(or plastic bag) and not evaporate keeping the inside wet all the time. That's why there are drains, to keep it dry. For stainless to remain stainless it needs to be allowed to dry.
     
  8. PAR
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    PAR Yacht Designer/Builder

    I don't see continuous welds, but do see stitch welds, which can have areas cut out between them.
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    No need for foam, just proper drainage.
     
  10. the brain
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    the brain Senior Member

    what about cutting up a old cooler and stuffing the POD.

    like will this make the stern more boyant?

    the POD is actelly welded all the way though the stich weld I assume this is the middle of the bottom?
    the only opening was the 1/4 in the front bottom I attached image of this.

    what I can't understand is why would they design the POD to have two sets of engine mounting holes I understand people wanting to adjust engine hight however when this is achcived there will be two open holes on the bottom? are these two open hole designed to either be sealed or there to let water in?
    thanks STB
     
  11. PAR
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    PAR Yacht Designer/Builder

    The cooler idea presents the same trapped moisture against the bracket issue and wouldn't be a good idea. Multiple holes suggests it's intended to fit a number of different applications. If they bother you that much, plug weld them closed.

    I believe you are over thinking this a bit. You have two choices, seal it up or let it drain a lot better than it currently does. The simple route is to provide better drainage. Conversely, you can seal it up (some aluminum plate and some TIG time), which will provide a very modest increase in buoyancy (because of it's volume and location underway), though certainly is more difficult.
     
  12. the brain
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    the brain Senior Member

    I've attempted sealing on the bottom where it contacts the transom and the sides w/ 5200. the lid helps a lot however it's not water tight.

    the engine holes are sealed so water is only entering thought the lid spaces and thogh the threads of the used engine mount holes (like is this possiable)? should the used engine mount holes have a thin layer of 5200 at least on the bolts outside?

    I was planning on cutting a PCV tube down the middle and placing it inside bottom of POD suspending the coolers syrofoam above the POD bottom.

    yes I do have a tendancy to overthink I allways want to improve situations.

    this POD needs more than improvemnets.
    Thanks STB
     

  13. ondarvr
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    ondarvr Senior Member

    Watertight compartments on a boat should be described as “once water gets in it won’t leak out.”

    Water will find its way into just about every space on a boat, and the size and location of that bracket won’t add much flotation, so I would say make it so it drains easily.
     
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