Reelfoot Lake (Stump Jumper)

Discussion in 'Boat Design' started by tnlakeboat, Mar 9, 2014.

  1. tnlakeboat
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    tnlakeboat Junior Member


    Got the new bottom wood cut......see pic.
     

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  2. tnlakeboat
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    tnlakeboat Junior Member

    New Wood

    Watson, shouldn't I run screws from bottom into new cross members once they are in place?
     

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  3. rwatson
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    rwatson Senior Member

    Hmm, interesting question.

    You could actually use the screws from the outside to pull the planks close up to the glass outer shell.

    The only question I have in my mind is of there are going to be any hassles fitting the cross members at the same time you are pulling the planks into the hull tightly.

    In the original boat, I would bet that the planks and frames were the whole boat, and they were all screwed and glued to form the hull - and the glass shell was done years after in an attempt to save the outer hull, over the top of the screws.

    Now you have a glass outer shell, and you are epoxying the whole business together, the need to screw the cross members from the outside of the hull is probably totally redundant and if you put screws in from the outside, you are risking water entry points that will destroy the timber.

    While I am not on the spot, my gut feel is that you should ignore the cross members until you have the wood planks safely glued up against the glass hull.

    Once the timber is cured tight, I would put a layer of glass over the inside of the hull, sealing the timber in totally. Then, using weights and/or 'push sticks' force the cross pieces to be glued to the top of the glass layer, hopefully not having to use screws or fasteners at all. Any fasteners that you do use, need to be removable and their hole refilled.

    Modern epoxies are super strong, and the main aim is to avoid as many 'punctures' that could let water into the timber structure.
     
  4. tnlakeboat
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    tnlakeboat Junior Member


    Very good points. Being my first go at this I am trying to look at options to reduce unnecessary work. I would rather avoid the whole screw thing from the bottom for sure. As long as the cross members support that is all that matter, right?

    The goal being that when 2-3 people are in the boat, the load is not directly on the bottom but the lower part of the sides where the members rest.

    The fiberglass was part of the original construction. In the days before they actually used sheet metal over the wood.
     
  5. rwatson
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    rwatson Senior Member

    Actually, probably not that straight forward. The cross beams are there to re-inforce the bottom. Say the cross means are 2" high, you could get the same effect if you made the bottom out of say 2" hi density foam and glassed the top and bottom. in effect you are making the bottom of the boat more rigid. If someone steps on the hull between the cross beams, the beams will resist the tendency of the whole bottom of the hull to bend or flex. The hull will definitely be strong enough to handle people stepping on the hull bottom once the beams are glued in - just as it can handle impact at speed of a rock or a log while traveling in the water..

    Once again, the members make the bottom resist the weight of crew - but its not necessary to restrict people to standing on the beams. having floorboard on top of the beams will tend to spread loads better, true, but I would bet that you wont put your foot through. Even dropping an anchor from waist high to the hull bottom ( when you are floating ) wont go through the 'floor'. The cross beams help a lot with that - especially if they are properly 'glued' to the 'floor' of the hull.

    I have never heard of small boats having sheet metal over wood - the rust/rot problem would have been horrendous.

    In any event, the hull would have been screwed down, then the glass applied over the hull.

    The reason that the wood rotted, is that it had water held against it by the glass. I would beat that the rot occurred where the glass delaminated slightly, allowing the water to collect.

    Sealing the whole of the inside of the hull with glass and epoxy will make for a lot stronger hull, as well as longer lasting.

    Epoxying the cross members to the top of that, will supply a whole lot of extra rigidity to the flat bottom, to resist impacts and load from the top or the bottom of the hull.
     
  6. tnlakeboat
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    tnlakeboat Junior Member

    You have to understand....these where good o'l boys back in the day that didn't venture very far. Guess they realized the advantages of glass later. The last guy to build the boats, Dale Calhoun was highly recognized for his work. My understanding is that one is actually in the Smithsonian.

    I appreciate your input. It has helped me finalize my plan. I just need to get the epoxy out and get a feel for using it prior to hitting the real thing.
     
  7. rwatson
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    rwatson Senior Member

    Smart move. A few small test runs will be super valuable.

    There are some good instructional videos on Youtube.

    A couple of tricks I find useful -

    Low heat from a hairdryer or electric heat gun, makes the job of wetting out the cloth much easier and more thorough.

    Plan to put the second layer of epoxy on, just as soon as the first one is hard to the touch, and still a little tacky. It saves a lot of fuss and sanding between coats.

    Pars technique of having part A and Part B of the epoxy, measured in separate cups prior to mixing has saved a lot of wasted goo. You can simply 'mix as you go' and not have to 'guesstimate' the total amount required.

    have fun :)
     
  8. tnlakeboat
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    tnlakeboat Junior Member

    Got the boat turned over. It really looks good. going to clean and prep for some additional glass. Thinking about coming about 1/2 way up the sides. You can see just how little draft.
     

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  9. tnlakeboat
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    tnlakeboat Junior Member

    I have read numerous post on opinions about the application of epoxy on here. There are some very knowledgeable folks on here and can't say how much I appreciate this forum for that. I have this little (18ft) lake boat that I am restoring and although it has with exception of a couple of small holes, a very solid fiberglass hull. I felt compelled to go ahead and strengthen her up a bit so one cloth and 3-4 coats of west system it will be. This will be followed by oil based olive drab paint.

    Guess you have to read, heed and go with what seems practical.
     

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  10. flathead65
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    flathead65 Junior Member

    If you don't mind me asking, how is that Honda GX coupled to the shaft and how is it engaged/ disengaged. I want to do something similar. A picture would be great.Thanks.
     
  11. tnlakeboat
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    tnlakeboat Junior Member

    Hey, don't mind at all. At work now but will get some pics this weekend.

    It is an inboard arrangement of course. Motor is mated to shaft with just two bolts. The shaft runs down a pipe at a slight angle and is bushed to create a nice slip fit. The prop is protected by a plate mounted on the very bottom of the boat. Pics will pretty much describe.

    Probably mention already but these boat where built by 4 generations of same family specifically for the application of running over stumps in shallow waters.
    Very hard to come by now. Last builder died in 2007. Aluminum Jon boats are pretty much the norm now.
     
  12. tnlakeboat
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    tnlakeboat Junior Member

    Bottom painted with two coats of oil based camo.
     

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  13. flathead65
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    flathead65 Junior Member

    When you have time. Is the bushing an oil impregnated bronze type? I would also guess this is a direct drive unit with no means of neutral. The only other question I have is the diameter of the prop? What a difference with the work you've done. I like it. Looking forward to pics. Thanks.
     
  14. tnlakeboat
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    tnlakeboat Junior Member

    I am not 100% about the bushing but it looks to be bronze. Here are some pics of the motor shaft, boat shaft and prop. The prop is approximately 8" diameter. Hope the pics help.
     

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  15. flathead65
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    flathead65 Junior Member

    That's some old school technology there. I think the best way would be to fill the Honda with oil until it spills out the fill port on the level and then install it in the boat. The fact it sits on an angle doesn't have an adverse effect because of the splash lube system. The dipper has plenty to grab and I can't see there being any starvation issues. They are mounted on 15 degree plates on race karts all the time, but inline with the crank. The prop appears to be brass? Anyway, cool boat and I think you're doing a great job on it. Four generations of builders can't be wrong. Thanks again.
     
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