Solid RIB tubes

Discussion in 'Boat Design' started by Darbio, Jan 8, 2019.

  1. Darbio
    Joined: Jan 2019
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    Location: Australia

    Darbio Junior Member

    Hi all,
    I have a 4.8m RIB that has sponsons/tubes that have come to the end of their life. As it seems with all RIB tubes, they are leaking air and ripping apart at the seams. A shame!

    Alas, I am looking into options, one being to re-tube it, but the other to be to build a set of fibreglass/aluminium tubes which I can affix in place of the existing ones. Re-tubing is expensive and potentially not worth it for the value of the boat, however fibreglassing is something that I have previous experience with and potentially may be cheaper and also lengthen the lifespan of the boat.

    There are a few mentions on the forums of people stating that they are going to undertake such a task, however no-one has posted any follow up on this, which makes me think that the project never happened.

    The hull of my boat is in top condition so it would be a shame for this to be the end of the whole thing.

    Any hints/tips warmly received.

    Cheers,
    Darbio
     
    waikikin likes this.
  2. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    Do you have a pic of it, or the same boat ? I don't get why you would want rigid "tubes", it would be easier to just build some sides on to it, possibly.
     
    Barry likes this.
  3. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Are the tubes made of Hypalon?
    What RIB is it?
    What year?
    Pics would really help.
     
  4. Darbio
    Joined: Jan 2019
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    Location: Australia

    Darbio Junior Member

    Thanks for your replies guys. @Mr Efficiency, I'm not sold on the idea of solid tubes - I would definitely consider building some sides, but I am wary that the hull was made for tubes and as such I'd have to look into stability etc. I was actually thinking of making the popular 'D' profile sides for the boat and making more space inside - it might be too narrow without the tube profile. Do you have any examples of people that have done this?

    Something like this is what I was thinking:

    Snap55.jpg

    The RIB is a PVC RIB, made in 2008. The brand is Silver Marine and the glue at the seams is just falling apart. I spoke to a few repair guys and they all told me that the PVC RIBs from that era which are glued and not welded are all starting to/have already fallen apart and warned me that it's going to be an ongoing battle to keep it airtight - it's already been re-glued in the past.

    Here are some pics:

    IMG_0083.jpg
    IMG_0085.jpg
    IMG_0104.jpg
    IMG_0106.jpg
    IMG_2792.jpg
     
  5. Darbio
    Joined: Jan 2019
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    Location: Australia

    Darbio Junior Member

  6. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    @Darbio, this is my design.
    Do you want me to explain some particularity about it?
     

    Attached Files:

  7. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Well, TANSL seems the man to answer this query, being his design.
     
  8. Darbio
    Joined: Jan 2019
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    Location: Australia

    Darbio Junior Member

    @TANSL I liked the "tubes" on the side, with the larger inside dimensions. Not sure if this would work on my boat though being a bit narrower. I like the flat gunwhales/tube tops as it allows an area for people to sit/lay down etc. My boat is just a runabout and won't be used as a diving platform at any time in the near future. Do you have dimensions? What materials were you going to use? Did it ever get built?

    @Mr Efficiency I'm keen on hearing other ideas too. Don't hold back because I posted that image. Specifically I am hesitant to not incorporate "tubes" (or something similar - even if rigid) for two reasons: because that is what the hull was designed for; and because the beam of the boat is 2.45m and 1m of that is tube, leaving the floor space only to be 1.5m. The boat might be too narrow at that width.
     
  9. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    TANSL is the designer of your boat, or am I reading this wrong ? He is best placed to advise what the options might be.
    Its a shame you can't buy giant pool noodles to strap on as a replacement for inflatable tubes, you would have no problems with deflation then.
     
  10. Darbio
    Joined: Jan 2019
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    Location: Australia

    Darbio Junior Member

    Aha! I see the potential confusion :). @TANSL is the designed of the boat that I said I liked the look of, not the actual boat that I have. Apologies - my bad!

    It is a shame that giant pool noodles don't exist. It is also a shame that you can't get LLDPE tubes (the stuff they make some kayaks out of) for a decent price. Hence my idea to built some from aluminium or fibreglass.
     
  11. TANSL
    Joined: Sep 2011
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    Location: Spain

    TANSL Senior Member

    Darbio, I'm not sure if you need to modify an existing boat or what you really want is to design a new boat. In any case, I would be happy to help you.
    The project was commissioned by a client, aluminum boat, waterjet, for diving work, and I do not know if any units were built. The intention of my client was to patent his idea, but I do not know if he got the patent. Yes, I know he was extremely happy with my work. LOL:).
     
  12. Tiny Turnip
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    Tiny Turnip Senior Member


  13. Barry
    Joined: Mar 2002
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    Barry Senior Member

    The problem that you may have in trying to build out of aluminum is the sealing of the fibreglass hull to an aluminum structure. Possibly too many compound curves in play between the tubes and the fibreglass hull
    If you are going to build full or, D style tubes to maximize inside storage space, you will still need a form/mold

    Here is an out of the box idea.
    Deflate the tubes. Remove the valve diaphragm portion so that the 1 inch opening is clear, mix up an amount of two component foam, you have to figure out the amount the foam will expand to so you will have a surplus to fully expand the original hypalon/pvc tubes.
    Pour in enough foam, rock the boat back and forth so you get good distribution along the floor, and when the surplus reaches the valve, close the valve. If the foam still continues to expand, you may be able to just cut some holes in the top of the tubes to let the excess flow out. The pressure from the foam should fill the tubes to the proper shape

    When you are done, you can cut the PVC off the foam male plug. Now you will have the hull to tube face interface created and you can decide then on what shape that you want to
    build the tubes using the foam mold that you have made. Then fibreglass what ever tube you build to your hull

    I am not saying that this will work but if I was considering building fibreglass tubes, I would give this a go. I don't think the two part POUR type foam is expensive. You might find
    that it takes a day or so to foam the tubes.

    You could call an inflatable repair company around your area to see if they have any abandoned, removed tubes that they could not repair but might be used as a
    trial run
     
    Last edited: Jan 10, 2019
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