Trophy 2152 WA (Boat Construction?)

Discussion in 'Powerboats' started by Catboy, Dec 12, 2020.

  1. Catboy
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    Catboy Junior Member

    I can't envision what this looks like. Are there any examples out there? The stringer grid is hanging from the bottom of the hull liner?
     
  2. ondarvr
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    ondarvr Senior Member

    Addressing several posts

    The foam will absorb water, the only thing that changed over time about the foam were some of the emissions aspects.

    It's a common misconception that at some time in the past foams were open cell, or somehow different.

    Foam is cheap and weak, it just happens to work well enough for flotation, at least for a decade or two.

    The equipment to spray foam is a bit finicky and requires skill to maintain and use. These skills are frequently lacking in a manufacturing plant. What you may get is something that expanded enough to look correct, but could be almost worthless.

    Even in good foam, over time the cell walls break, and what was once a closed cell foam more resembles a sponge.

    Just because foam is enclosed, doesn't mean it will stay dry.



    Sometimes the stringer grid is a separate molded piece thats dropped into the hull. It will resemble a wooden stringer grid in shape and size. For the most part they get bonded to the hull, depending on the adhesive and the design, they may or may not get glassed over.

    Most aren't gel coated on either side, no need for it on parts like this that are buried in the hull. Although they may get coated at a later time in production.

    In some designs the hull liner is also the structure that reinforces the hull, just like the stringers would. The shape is different because it may also incorporate stairs, spaces for storage, fish boxes, coolers, seat bases, etc.

    In this design there maybe larger spaces for foam, and foam may be used to help stiffen the liner.

    These are generalizations, each manufacturer may have their own twist on how it's done. It can even change from one length boat to next of the same model. Or even in same hull, a CC may use the same hull as the cabin version, but a totally different stringer system and liner. Same with going from I/O to OB.
     
  3. fallguy
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    fallguy Senior Member

    Marine foams are inexpensive. I'd look for any opportunity to add foam where possible after reading the last post.

    And, be conscious about adding weight in a rebuild.
     
  4. mudsailor
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    mudsailor Junior Member

    More like 4-6” wide and don’t forget the transverses as well, I would guess closer to 20 cubic feet, so enough to stop it sinking
     
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  5. mudsailor
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    mudsailor Junior Member

    Never a trophy with the stringer incorporated into a hull liner, it makes the boat look good but is typically a really poor hull structure....
     
  6. mudsailor
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    mudsailor Junior Member

    Lots of changes in the 2000’s, proud to have been involved.....
    If the hull molds changed...then typically everything changed.....best way to know is to check the Hull ID for the two letter code, 2052 and 2152 are the same boat.....it was built for a long time with sometimes minor changes changes, sometimes bigger (like the stringer change)
    Trophy never shared a hull design.....the Bayliner and Maxum runabouts did (same hull mold) and with the cruisers they sometimes shared the same running surface (but a different topside design/transom design so had a different hull mold)
     
  7. mudsailor
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    mudsailor Junior Member

    Apologies for not being clear....a lot of companies mold the stringers with gel coat ‘out’ and then glue them in place with Plexus......IMO a really poor way to build them (very little continuity across the tops of the stringer) and then a blind bond with very expensive glue.
    The trophy stringers after being demolded were placed in the hull and fully glassed into the hull, a straightforward, easy and very inspectable way of building boats.
    Transom should be 1 3/4” of plywood and the rest glass (mix of chop and roving)
    Per NMMA Regs all outboard boats between 20’ and 26’ LOA would have basic flotation.....and we would always test the boats to make sure
     
  8. mudsailor
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    mudsailor Junior Member

    Foam is 2 part, assuming it is mixed correctly then closed cell, problems arise if the mix equipment isn’t calibrated.
     
  9. fallguy
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    fallguy Senior Member

    can you shed any light on how the Robalo might have sank off Florida with the firefighters? The boat was never found.

    Did the regs kick in on a certain year?

    Or t top added takes it over?

    Apologies to the OP, but hoping the q&a helped him.

    Massive Search Continues For Missing Port Canaveral Boaters https://www.mynews13.com/fl/orlando/news/2019/08/18/2-boaters-missing-since-leaving-from-port-canaveral
     
  10. mudsailor
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    mudsailor Junior Member

    No idea......but there are differences between USCG regs and NMMA requirements (which reference a subset of ABYC rules) for flotation and Ultimate stability is not measured. The rules are based on historical accident data, not on engineering logic.....so a 19’11” outboard powered boat needs ‘level flotation’ under USCG rules, but a 20’1” stern drive boat needs no foam under USCG. Now NMMA requires more than the basic USCG requirements which is good.
    Overall the European rules (ISO rules) are much more logical, they balance foam needed against stability against self draining cockpit against freeboard and down flooding height.
    As a note from the early 2000’s onwards all the Bayliner//Maxum/Trophy boats met both USCG and ISO rules no matter where the boat was sold
     
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  11. fallguy
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    fallguy Senior Member

    Thank you so much. I knew there was some nonsense involved. We now return to regular programming. My apologies to the OP.
     
  12. Catboy
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    Catboy Junior Member

    This 2152 has an I/O not an O/B, how does that change the way the regs look at the boat and it's requirements? It's very reassuring to think this boat won't sink!
    Any thoughts on whether this boat would roll once swamped? It does have a hardtop.

    Fallguy - this was a worthy detour!

    I think I'm clear on the construction, it all makes sense, I'm glad there aren't any wood stringers and I a appreciate all the comments.
     
  13. mudsailor
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    mudsailor Junior Member

    Quite a bit for flotation, but Trophy made them them both the same, ie built the boat above the minimum requirements, but swamped stability is something that is not calculated or checked, that much free surface is never a good thing.....just because it won’t sink doesn’t mean you ever want to be in that situation of hanging onto your barely floating boat. If it’s that rough....wear a life jacket and locator
     
  14. gonzo
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    gonzo Senior Member

    To keep a boat from capsizing and float upright when swamped, the foam or watertight boxes need to be under the deck and the upper part of the sides. If the foam and boxes are in the bottom, the boat will likely flip when swamped.
     

  15. Catboy
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    Catboy Junior Member

    Can you please speak a little to the typical process for bonding the plywood to the bottom of the deck liner (inner layer in the mold) and transom areas?
    Sealing the plywood & steps in bonding of the plywood core to the inner layer?
    There are also some vertical plywood panels with fiberglass on each side. Do you think those plywood panels are Greenwood also?
     
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