Homemade RIB howto?

Discussion in 'Boat Design' started by Saqa, Dec 5, 2013.

  1. Saqa
    Joined: Oct 2013
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    Saqa Senior Member

    Hi fellas, ever since the thot of using the sponsons on one of these things
    http://www.sevylor.com/Coloradotrad...l-P2037.aspx?gclid=CI3LoI20jLsCFYWDQgodIz8AvQ
    on my boat, I am obsessed with making a lil RIB using them

    I can imagine making a s&g vee hull about 10' long and 1.2m wide using ply and only making very short height sides, just enough to give descent hard chines and a sole and a transom

    Cant think of how to then attach the sponsons to the hull. Do I duplicate the hull with PVC fabric or similar and sew the sponsons on then nest the hull inside?
     
  2. Grey Ghost
    Joined: Aug 2012
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    Grey Ghost Senior Member

    Could be D shaped tubes or fiberglass hull shaped with half rounds to accept the tubes.
     
  3. nimblemotors
    Joined: Jun 2009
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    nimblemotors Senior Member

    I believe the inflatables are glued to the rigid boat.
    Visit rib.net they have lots of projects showing how the boats are made.

    [​IMG]
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Unless you are a diver or a rescuer, what is the object of the exercise ?
     
  5. Saqa
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    Saqa Senior Member

    Mr Efficiency, I have been too busy actually making a boat then keyboard bashing but while waiting for the paint to dry thot to see whats happening in the virtual world

    I asked a technical question on an aspect of a project I am interesting in working on. Ways to fit inflatable sponsons on a 10' barebones stitch and glue hull? Something that might be fun and practical craft that is easily stowed and carried yet rigid in the right place, cheap to make where even a second hand RIB would be too costly due to lack of availability. And to make use of something that might end up sitting and rotting due to disuse

    Maybe a micro RIB is only to be used by divers and rescuers where you live but I am sure I wouldn't need a special permit from them to use one here in Fiji for having a wicked old time hooning around the flats behind my in-laws farm with the 8hp outboard, setting traps for muddies and being able to fit wheels to the transom and drag its expected minus 40kg total weight back over 200m of mixed grass and dirt terrain and lock it up in the farm shed so it doesn't get pinched

    I am sure my relos there also wouldn't have to apply for the aforesaid permit to be able to use it as a tender for their 26' wooden panga style launches, so they are not forced to beach their collective 4 boats on dodgy mud and wait at the mercy of tides to head back out and in in pursuit of their livelihood. Being able to collapse the sides and stow it away on the larger boat if need be Its also called building goodwill, building a place for yourself in the minds and hearts of people after all the anger in running of with and marrying their youngest daughter

    Now that I have met your conditions for participating in a technical discussion, lets see what you have to offer to the world of attaching an inflatable bag to a rigid surface :/

    Why do it? This is a repeated question thread after thread on this forum. I do not remember the rules of Boatdesign.net specifying that if you want advice or discussion on a technical aspect or concept, you have to first provide the whole rationale behind whys of your project :/ May I suggest that maybe forums might be the wrong type of online activity for you
     
  6. Saqa
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    Saqa Senior Member

    Yeah I thot of the hollow tubes but made from stitched tarp like fabric but using rigid tubes would add weight that I would like to keep off
     
  7. gonzo
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    gonzo Senior Member

    The material for the tubes is either Hypalon or PVC. Either one needs the proper adhesive and building techniques. They have reinforcement tape and bulkheads. It is not impossible to do since RIBs are assembled by hand. However, they spend a lot of time and wasted material in researching how to cut and fit all the parts.
     
  8. Saqa
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    Saqa Senior Member

    Hey mate, do you know if expanding PU Gorilla glue will be strong enough for the job and bond glass to nylong fabric? Thats the strongest glue I can get my hands here that is waterproof
     
  9. Saqa
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    Saqa Senior Member

    True, I used to work at the Achilles distributor in Sydney. Did learn some of the tricks of repairing the boats during downtime but I dont have the gear here in Fiji. The sponsons on the canoe are currently stitched on by the factory. Unlike regular inflatables, this thing is supposedly a nylon fabric jacket fitted with PVC bladders making it a bit more rugged

    Somehow lacing or stitching them onto a simple veehull made of just the glassed ply bottom panels and transom looks to be simplest but I hve never done anything like that so do not know if that is feasible or safe
     
  10. Saqa
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    Saqa Senior Member

    I should add That I have seen the folding portabote online and thinking something like that maybe
     
  11. DCockey
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    DCockey Senior Member

    My understanding is that while Gorilla glue will expand as a foam to fill voids, the strength is reduced by a considerable amount.

    Also consider mechanically fastening the tubes in place. Add a flap along the top and bottom of the tubes and then screw or bolt the flaps to the hull.
     
  12. Saqa
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    Saqa Senior Member

    Thats an excellent idea, thanks for suggesting that. I think I know have the means to make this feasible
     
  13. Richard Woods
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    Richard Woods Woods Designs

  14. Saqa
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    Saqa Senior Member

    Basically since all I am looking at at doing is a flats hooner and occasional tender for use in a large bay always in the lee of Volivoli peninsula here in Rakiraki Fiji, I am now inclined towards a flat barge types hull with a square top view made safe and stable by recycling the sponsons from the Colorado

    What do you guys think of this?
    10' total hull length

    4' hull with plus sponsons increasing beam

    1' tall sides

    Using sheets of quality 6mm exterior ply

    Panels attached to each other using 1"x1" batons of a quality marine rated local semi hardwood called damanu, its clear lumber and very resilient

    4-6 batons under the hull length to stiffen things up and provide some abrasion protection for the bottom

    Would I need to make a skeg using that lumber? I dont know how long or wide will be needed, lumber is 1" thick

    Left over ply to make a fore deck capping the bow with the fuel tank and gear stored underneath
    A baton outside the chine forming the flap to screw down the sponson along the chine and same job up the top also forming a stiffener for the gunnels

    Transom, damanu plank with a Tee middle plank bolted on to take the motor at a correct height

    All glued and screwed with gorrila, its $50 FJD a bottle which will do the whole boat compared to the $200 FJD epoxy that will be needed

    I have a gallon of laminating resin which I bought when starting on my other ongoing project here http://www.boatdesign.net/forums/boat-building/building-stitch-glue-boat-fiji-48653.html but never used as I decided to go epoxy on that after advice received on this site. I also have heaps of 600gsm roving that I bought to use on that boat but never did again after advice on here. Maybe I can use them to laminate this hull and its either polyester resin + 600gsm + car paint or penetrol+marine *****l on this hull

    The smallest motor we have is 8hp and will have a 12' pole for stealth work
     

  15. Saqa
    Joined: Oct 2013
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    Saqa Senior Member

    Richard, the dogs are exactly what I intend to replicate by recycling the sponsons from this new canoe that will rot with disuse
     
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