Bass boat conversion question

Discussion in 'Boatbuilding' started by TheWizzaardd, Apr 6, 2017.

  1. TheWizzaardd
    Joined: Mar 2017
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    TheWizzaardd Junior Member

    Since I began looking into boat building and construction I have been seeing all of these different builds for converting an old row boat into a decked fishing boat which is something I m quite interested in doing. My question is what are the frames anchored to? It appears as if they build the frame then simply place it on the hull and screw the deck to it, which doesn't seem right. I assume I am missing something. An example is https://www.youtube.com/watch?v=ZttwiEDTSUs or https://www.youtube.com/watch?v=10rshYiDoIc

    It seems like something interesting to try, and every summer rowboats pop up for sale all over the place for pretty decent prices.

    also I saw people adding supports to the transom so they could either increase the hp or modify it so they feel safer using max hp with an older boat, such as from the 50s. Good or bad idea? they sort of added a2x6 beam from the transom to the first aluminum bench seat.
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I wouldn't follow any of the advice on the the 2x6 equipped aluminum V bottom you posted. It's ridiculously overbuilt, so much so it'll need another 20 HP just to do the same speed it did previously and this also dramatically lowers the boat's stability and capacity.

    The other one at least uses 2x2's which are still more than you need, but a fraction of the weight of the clown using 2x6's. Unfortunately, he still used 3/4" plywood decking panels. I always wonder what they're thinking this needs to hold up, a full size fridge, full of beer? Of course he also uses carpet over the wood, which is a God send to people like me in terms of future work, because carpet on wood is a guarantee that you'll be back to have it replaced. His other "upgrades" are good ideas.

    To build a casting deck you only need an aft bulkhead, some 1x2 stringers and some 3/8" plywood to fit the deck space. On an aluminum boat you don't drill through the side of the boat, into frames. The frames and other support structure (stringers, cleats, etc.) are attach (screwed) to existing structural elements, like the chine log, bilge stringers, etc. These are riveted or welded to the aluminum hull shell, so an appropriately sized screw doesn't penetrate the hull, just the stuff inside it. I just did this to an old 14' tinny and used a couple of 8' - 1x2's and about 2/3's a sheet of plywood. I added maybe 20 pounds to the boat total.

    Most of the time, if you make a template for the casting deck, running from chine log to chine log, the plywood will neatly just lay there, maybe with a few screws to insure it stays put. The trailing edge will need some support, so this is where you put a bulkhead, which can have a hole (or two) cut in it so it's a ring frame instead. Screw a 1x2 along the top of this 3/8" plywood bulkhead, so the decking plywood has something to land on. Additionally, if any of your well fed friends will join you on this deck, you'll want a few longitudinal stringers, notched into the ring frame. These tie the casting deck plywood to the ring frame once it's all screwed down. Space these fore and aft stringers on 12" - 14" centers and let them land on the chine log. They're just stiffeners so the plywood feels firm under foot.

    Instead of carpet, consider truck bed liner or a "FlexSeal" coating. It's tougher, waterproof, has much better under wet foot traction and can be repainted and pressure washed when the time comes.

    I fix these "tinnies" all the time and I usually pull out a lot more wood than I put in. The boat is rated for what it's rated for and you can screw all the 2x6's to the transom you want, but this doesn't make it a good idea or even legal. There's a formula for figuring out how much HP you can toss at this puppy and going over this sounds like fun, but odds are I'll read about you in the paper some day (We read about people finding a way to drown themselves in boats regularly where I live). Besides, you don't want to take that boat much over the mid 30's anyway. The hull form is a type that will beat you (and the boat) to death are speeds higher than this. Tell me the boat's length, transom height and width are and I'll tell you how much you can safely put on her butt.
     
  3. TheWizzaardd
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    TheWizzaardd Junior Member

    I figured it was too good to be true hence the question. I just wanted to make sure that I took nothing from that video seriously.

    So I can anchor to pretty much anything as long as it isn't the hull?


    I was probably going to use 1x2s as I usually have a bunch laying around for various projects and they are usually pretty cheap. I was going to seal the wood as I had looked up carpet prices and then immediately changed my mind. flexseal is probably the way to go.

    I was just using those videos as a reference to the fact it didn't look like they attached the decks or frame to anything not the ludicrous over framing. I had no intention of making it that beefy unless it magically let you put a 50 hp motor on it. But in reality I was going for light as possible with the framework and decking because speed is fun. I also want most of it to be the flat deck so no way in hell am I putting 14'x5' worth of 3/4in plywood on that thing with a 2x6 frame.

    Thank you for the information, very helpful.

    When I get the cash to start this I'll probably post pictures seeking guidance. I want to do some weird stuff so help will be appreciated.
     
  4. jorgepease
    Joined: Feb 2012
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    jorgepease Senior Member

    ... or use a really thick foam core panel to make the clear span, and just glue it. If you expect lots of weight or the span is great, glass some stiff backs - vertical braces to the bottom. You can build in hanging boxes and put hatches for storage etc... do it all off the boat and drop it in as one piece.
     
  5. TheWizzaardd
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    TheWizzaardd Junior Member

    Does the wood type for the stringers matter? If pine will make the whole thing fall apart, which I doubt, I won't use it. I just have a crap load of 1x2s and 1x3s from when we redid our kitchen. So it doesn't matter if they rot out quicker as I have oodles of replacements, but if there are complications related to pine that I am not seeing I will stay away.
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The cheapest and easiest way to get 1x2's is to buy a good looking 2 by something (2x6, 2x10, 2x12, etc.) and run it through a table saw, set at 3/4". Each off cut will be a 3/4"x1.5" piece (what a 1x2 is). When doing this, it's important to know what is a good piece of wood and the easy way to do this is buy big stuff, like 2x12's that at 16' long. The reason is simple, you need bigger, older trees for these sizes, so the wood will have tighter grain, denser stock and you can easily pick through a few in a pile, at the big box store to find deadnuts perfect boards, no knots, splits, straight grain, etc. Go down to the local big box and look through a dozen 2x12x16' boards and you'll quickly see what I mean.
     
  7. TheWizzaardd
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    TheWizzaardd Junior Member

    I know what you mean with the boards. If I had a table or band saw I would totally do that. All I have at the moment is a circular saw and I am the one person alive who can't cut straight with a circular saw so I will avoid that. I could rig up a table saw.. but that is how you lose fingers so I will probably avoid that too.

    These boards are from cabnits from the 60s, before the quick growing pines were used, so the grains are much tighter and it has surprisingly few knots. I just wanted to make sure using hickory or mahogany didn't magically make my boat fly as some would suggest. Ill drive to eight stores before I will take you standard wavy gross knotty 1x2
     
  8. PAR
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    PAR Yacht Designer/Builder

    A circular saw can be setup to act as a mini table saw. You simply screw a cleat (1x2) onto the bottom of the saw, set to leave 3/4" of material from the blade edge. This "guide" thingie on the bottom of the saw will insure you have a straight line, assuming you just keep constant and consistent pressure against it during the cut. There are dozens of videos about doing this with a circular saw, some better than others.
     

  9. TheWizzaardd
    Joined: Mar 2017
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    TheWizzaardd Junior Member

    I shall keep that in mind. Ill still probably find a way to muck it up, motor disabilities are good for that, but we shall see.
     
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