Design tip on inclosing a 22” cruiser

Discussion in 'Boat Design' started by the brain, Sep 6, 2016.

  1. the brain
    Joined: Sep 2016
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    the brain Senior Member

    Design tip on inclosing a 22” cruiser

    I have a 1977 22’ Starcraft Chieftain would like to inclose from rear of hardtop.

    The boat is aluiamin I’m not sure undiced which type door to have slider or a household storm door.

    The rear wall will hold my generax generater above deck behind the helm station,

    I would like a bendable shelf about table height for a small gallery hotplate/ fry daddy oil fryer.

    edit I plan to fabup some window flanges for the side windows this will the easy part.

    if anyone here has done this type of inclosesure please post images.
    I like the way the rod holders and net are located on this boat.

    http://www.hewescraft.com/products/ocean-pro/

    Thanks for any advice on design
     

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  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    This isn't a terribly difficult thing, though is more complex than you realize, I think. As far as the shape and size of tables, counters and other bits of furniture, well this should just be an aesthetic call, so long as you think lightweight and stiff. I have no idea what a bendable shelf might be. Rod holders can be easily placed about anywhere. Use a backing block for the fasteners to have something to bite into.

    As far as the door, sliders from someone's family room or a regular house door probably will not be your best choice. The boat's just not big enough nor dry enough to consider house parts - they just rust and/or corrode, especially around salt water. These pieces are also heavy, which you want to avoid, so consider an aluminum "cored" door, which is foam filled, with aluminum skins bonded on. Depending on the alloy, it'll hold up better. Also the hardware (hinges, latches, etc.) can't be homeowner grade stuff. Stainless or bronze are the usual choices. Don't be fooled by stuff that looks bronze, bring a magnet and test it. If it sticks, it's plated steel and it'll rust quickly.

    The bulkhead can be a number of things, but given it's an aluminum boat, I'd be inclined to use aluminum over a tubing frame. You can pop rivet, screw or bond it in place.

    If you bring the control cables and steering linkage sideways through the splashwell wall, you'll have a better lead to the engine. Also, make the cables the right length for the job, by coiling, looping or generally taking up some length, behind stuff, so when they do exit the splashwell wall, their length is just right.
     
  3. SamSam
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    SamSam Senior Member

    Have you considered this type of thing?

    [​IMG]
     
  4. jehardiman
    Joined: Aug 2004
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    jehardiman Senior Member

    The best advice is to make it light, or really not heavy, and make sure it doesn't weigh much.

    One of the most common causes of fatalities in small boats, especially working craft, is a retro fit that encloses space and adds weight high.

    Did I mention make it light?
     
  5. the brain
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    the brain Senior Member

    canvs looks OK but it seams to me a lot of time setting it up.

    I want the wall so I can have generater 500BTU AC sys. and small galley.

    audio/video entertainment will be windows media center.

    probablley use a aluiamin household storm door.

    here's what I'm iminatating
    http://www.hewescraft.com/products/ocean-pro/

    __________________
     
  6. the brain
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    the brain Senior Member

    yes the wall will be made of aluiimin.the actuelle wall will be light in weight however the generater weights in at 50LBs AC another 15-20LBs fry daddy 2LBs.

    I would prefer to have the generaters exhaust tube thought the wall.

    this boats capisty is 2900LBs of people and gear inside boat.

    yes the wall will be made of aluiimin
     
  7. Barry
    Joined: Mar 2002
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    Barry Senior Member

    I would recommend a Dutch Door, the top half opens independently from the lower part of the door. Swing type, extra ventilation

    1 inch square tubing welded frame, .063 sheet inside and out with 1 inch foam in between would work
     
  8. Barry
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    Barry Senior Member

    Or unless it is 403 stainless which is magnetic.
     
  9. PAR
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    PAR Yacht Designer/Builder

    18-8 (304) stainless really shouldn't be used on a salt water boat, though I see it a lot anyway.
     
  10. the brain
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    the brain Senior Member

  11. the brain
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    the brain Senior Member

    Starting the enclosure rear wall.

    I have the first of three wall uprights cut. Will require me to cut the inside gunwale (it’s designed to hold the top of starside fuel tank also to protect control cables/ steering tubes ect. All this stuff is tucked up against gunwale. So I think I can slide the upright outward on both sides.

    Notice the portside cover only protects the top of port fuel tank.

    Plan to fab the window into the aluimin (flimsly) door then reinforce door.

    Door will need to be lowered a tad.

    I will relocate ladder to portside due to steering tubes then have plateform on starside for diving catch cooler collection or a plastic 6 gallon fuel container.
     

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  12. Barry
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    Barry Senior Member

    1) How are you going to attach the bottom of the uprights into the hull? Ie to the sheet aluminum hull bottom or to stringers?
    2) Cutting the gunnel might cause you some issues as that is what gives the side of the hull a considerable amount of strength
    3) What is the thickness of the gunnel? There should be a hole drilled somewhere through it to determine this thickness.
    4) Before you cut the gunnel, send us a sketch as the gunnel is a structural member that FLEXES quite a bit when pounding the waves and there is a good chance that you will have welds cracking. Ie I am assuming that you are intending to cut the gunnel and weld in the upright??? If you send a sketch before hand, there are some methods to perhaps reduce the chance for work hardening and then cracking due to the stress concentrations that you will impart into the gunnel/upright joint.

    AN EXAMPLE WOULD BE IS TO NOT MAKE A VERTICAL WELD ACROSS THE GUNNEL, there are proven welding procedures to reduce problems here

    5) Any idea of the hull bottom thickness as well


    You do not want to weld in an upright onto the sheet floor. This hard spot will almost certainly cause stress concentrations that will crack over time. And sometimes not a lot of time
     
  13. Barry
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    Barry Senior Member

    Looking again at the upright by the gunnel, if it were my boat and I had to mount this upright as you are wanting to I would cut the upright immediately above and below the gunnel. You can then weld in the upright upper and lower pieces as the welds will be in a plane the same distance from the neutral axis of the member. Do not weld vertically across the gunnel or there is an extremely good chance that you will have problems.
     
  14. the brain
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    the brain Senior Member

    this is a walkaround gunwale the uprights will be inside of gunwale look closely at the piece I'm cutting (only on star side) the brown piece extends the length of star gunwale it's designed to protect the top of the fuel tank it isn't a structaule piece.

    I attach the bottom of uprights w/ small angles rivoted to uprights then screwd to floor floor is screwed to stringers.

    the top upright angle is revioted to hardtop then bolted to upright (some it can be easiely dissassembeled.
     

  15. Barry
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    Barry Senior Member

    I assumed that the brown piece was a support that is located between the gunwale and the chine
    As you referred to it as cutting the gunnel, in your Picts and comments, I used your terms.
    If this piece runs the length of the boat or say from the transom to close to the front, then it is structural to stiffen the side of the boat. ANY time a member takes a load there is strain, stretching, of the piece, (hopefully elastic) and if there is a stress concentration due to, some options, a stiff cross member or even a weld in an incorrect direction, a notch from a poorly finished weld, you can produce work hardening, then cracking then failure

    Rivets will work fine but with material as soft as aluminum, they often lose their tensile load and can get sloppy
    Our preferred method was a flat washer wherever a bolt head or nut was
    going to touch the aluminum. Then a split washer, not to keep the nut from backing off but to keep some tension in the bolt, then a nylock nut to tighten things up
     
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