Custom Extended Swim Platform

Discussion in 'Boatbuilding' started by tpenfield, Jan 8, 2019.

  1. tpenfield
    Joined: Dec 2016
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    tpenfield Senior Member

    I got the coring material installed and the 'J' Bolts installed.

    IMG_2465.JPG

    IMG_2466.JPG

    IMG_2467.JPG

    I am running short on resin, so things will have to wait until I get more supplies.
     
  2. fallguy
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    fallguy Senior Member

    Glass looks dry.

    Maybe you are cutting the dry stuff away?
     
    Last edited: Apr 29, 2019
  3. tpenfield
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    tpenfield Senior Member

    Yes, the core strips and glass weave is only wet-out underneath (for now). The top and rest of the glass weave will be wet-out with the next layer of glass/resin.

    Having all of the strips and glass weave pieces pre-cut and organized worked out well. I put the core down in no time.
     
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  4. tpenfield
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    tpenfield Senior Member

    Progress update . . .

    I have the core pieces glassed in on both decks of the platform.

    IMG_2484.JPG

    The 'navtruss' worked out OK . . . a bit thirsty on the resin, but fine. I had to go pick up a few more gallons of resin. The VE stuff has gotten expensive over the past year . . . sort of wished I had started with poly resin.

    I have the remaining embedded hardware installed.

    IMG_2486.JPG

    Next steps will be a bit more glassing and trying to figure out 'boxing' in the rear edge area of the platform to make it like an outer skin.
     
    Last edited: May 6, 2019
  5. fallguy
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    fallguy Senior Member

    Quite a project.

    Decoring that would be a pita unless you could use a router. If that is what you mean.

    Another option would be to laminate a piece of 1708 on..... You could laminate it on a plastic bag and cut it out and glue it on with thixo. Then trim it.

    Not sure if I fully understand, but trying to help if possible.
     
  6. tpenfield
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    tpenfield Senior Member

    Here are some 'bevel' pieces installed at the step-down area to provide some stiffening (hopefully)

    IMG_2493.JPG

    Here they are all glassed in with 24 oz WR.
    IMG_2495.JPG

    I still got to figure out finishing the rear area, but in the meantime, I'll work on some pylon stiffeners.
     
  7. fallguy
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    fallguy Senior Member

    I would have just filleted and taped that.

    A gusset would have been better still.
     
  8. tpenfield
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    tpenfield Senior Member

    Perhaps they are gussets :)
     
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  9. tpenfield
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    tpenfield Senior Member

    Here is a wire frame diagram of what I am thinking for the 'boxed in' area in the aft-most section of the platform (purple lines). This approach will require threaded inserts into a starboard material backing (white lines) for the ladder mounting hardware, which could be problematic if the threads ever fail. If I left the ladder mounting areas open, then I could use a typical thru-bolt, but the boxing structure would be more complicated.

    The purpose of this structure would be 2-fold . . .
    1. Support the ladder abutments
    2. Provide some streamlining for the underside of the platform.

    AftStructure104.jpg

    I'm thinking I could build the box structure from the 1/2" rigid urethane foam sheets that I have left over from the core material, and then fill the cavity with pour-in foam. (USCG approved 2# density is what I have on hand). Afterwards, I could round corners and do some shaping, then cover it with glass. Might be good to vacuum bag it for curing.

    Thoughts?
     
  10. tpenfield
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    tpenfield Senior Member

    Another option would be to go with thru-bolts for the ladders, in which case the boxing structure would need to look something like this . . .

    AftStructure105.jpg

    It would be a bit more tedious, but the ladder mounting would be more reliable.
     
  11. fallguy
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    fallguy Senior Member

    Too tired now. Try for tomorrow, sorry.
     
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  12. tpenfield
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    tpenfield Senior Member

    I think I prefer the thru-bolt approach vs. the threaded inserts for mounting the swim ladders. I will probably set up a resin infusion to apply the fiberglass encasing to the aft structure that I have drawn in post #145. I think I can set up seal tape around the perimeter of it once the foam is all done and shaped. Then set up a couple of feed lines, a vacuum line, and the bagging.
     
  13. fallguy
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    fallguy Senior Member

    You can thru bolt, but you might want to sleeve the core if I am understanding.

    The minimum, of course, would be overboring and filling and redrilling thixo.

    I hate to mention it, but I am not a fan of using light foam here. I would probably use a minimum of 12# or even use plywood (I doubt you would). I just don't trust 5 pound foam for any odd forces.

    Of course, I am just understanding the concept that these will be holding ladders. I am not fully understanding the forces and where a light foam might fail from a 250# person climbing up and putting some odd torque on it.
     
  14. tpenfield
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    tpenfield Senior Member

    Thank you. Your input is making me think through the design in more detail; much appreciated. :)

    The foam is just to fill the void and make the shape. The strength will be in the fiberglass (hopefully) . . . not really relying on the foam for anything but the shape. A triangle - being the strongest shape - is what is designed around the areas of the swim ladder support, where the stress will be the highest. Basically, a triangular shape on each side of the bolt locations - amounting to 8 triangular shapes. So, I'll just want to make sure I use enough fiberglass in those areas.

    I could also contour a rib in the flat areas between the bolt locations for added stiffness for when the 'fat guy' climbs the ladder. :D
     

  15. tpenfield
    Joined: Dec 2016
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    tpenfield Senior Member

    I filled in the surfaces on my wire frame drawing for a more realistic representation of what it should look like. . . .
    .
    ESP105B.jpg
     
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