Help drawing and design Texas Scooter boat

Discussion in 'Powerboats' started by Aransas Flats Rat, Jan 31, 2020.

  1. Yellowjacket
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    Yellowjacket Senior Member

    You don't need the caps on the stringers on the top. That's just added weight if the deck is bonded down with goo. At the most you could use a 1x1 on each side of the stringer plywood and that would be plenty. You are correct that if you use stringers to attach to the motor board you'll provide the necessary support. I would bring the stringers through the deck and along side of the motor board. Then you can add blocks ahead and behind the motor board and that would provide support to the motor board and spread the load to the stringer plywood. Screwing into the motor board is a bad idea as it will just split. For the stringers alongside the motor board those need to be 1/2 inch plywood. For the other stringers 3/8 is more than fine. You can cut holes as shown in the pictures to reduce weight, but don't get too greedy. You need to tie the bottom and top of the stringers together and if you cut too much out you'll get cracking as they won't be able to take the loads.
     
  2. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Thanks, that makes perfect sense, I didn’t plan on using any screws with the the exception to hold together until bonded, laminations on stringers would be, set in thickened Epoxy, 1/2” fillet taped three layers (offset) 12-17 oz biax 6” tape then glass over entire stringer.
    I like the idea of just using 1x battens to provide a bonding surface for the deck.

    As per tying stringers together I was thinking about traverse frames/bulkheads, taped in to the hull in the same means as stringers. In my mind this would create the hull as one unit when completed splitting the loads equally.

    I’m stuck on the bottom shape, I’m not sure with this type hull if the hydrodynamics really comes into play as I think I understand the first bottom shape example is to transform the longitudinal direction on the force of water but is the offset necessary aftwards.

    To me there would be not much difference with a flat bottom hull so in my mind I’m thinking the typical flat bottom shape would be sufficient.

    I could have this all wrong and would appreciate comments and or corrections as I’m really trying to learn.
    Thanks
     
  3. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Also on the lightening holes in stringers and transverse frames I would stick to the rule of 3” as I understand it.
     
  4. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Here is an example of the transverse frames/stations. Notice the notches for attaching to stringers. Would be bonded with thickened Epoxy and taped.
    E11C0F85-1C71-418C-A894-3601D061BD5A.png
     
  5. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Ok so here is were I am stuck on and need help.

    I’m lost on where to get started. I am confident in the concept and I accept full responsibility. I have fished off one many times in Texas; to most it’s confusing and hard to get them to steer from the norm of max freeboard and performance design and they think why In the world would you want minimal freeboard and no sides; it's about functionality for its purpose.
     
  6. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    I have a couple of plans that I feel I can manipulate to this hull.

    This is the one I feel would be the best fit. It is a 20’ sold by Boat Builders Central, it is a very stable hull easy planing.

    Would like some suggestions or direction to convert.
    2C0BFE9F-3B58-41B8-817F-F20E25ED6295.png
     
  7. bajansailor
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    bajansailor Marine Surveyor

  8. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Thanks. I have the complete plans for this model. No concern with loosing stufff as it’s a sole purpose boat. Flounder gigging
     
  9. Yellowjacket
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    Yellowjacket Senior Member

    The one thing that you need to think about is that with a very flat bottom and almost square chines, this boat is going to run flat and skid a lot when you turn. You'd need a strip on the bottom (like a 1x2) as a minimum or more better would be a skid fin that was about 4 or 5 inches deep mounted about 3 feet forward of the transom.

    Another approach is to make the hull with "no trip" chines so that the boat rolls into the turn as opposed to just skidding. Having some roll is good because things won't slide off the deck and people won't have to hang on as hard when compared with a flat turning boat. If you look a the plans and hull shape of the Diablo you'll see something that is a lot better than a flat bottom both in terms of ride and handling. You could "break" the bottom by making the center section four feet wide (using one piece of plywood) and then have some deadrise in the outer two feet of the hull on each side. This wouldn't make it any harder to build, but the boat would handle a whole lot better and when sitting it isn't going to have much difference in draft. That is probably what I'd do just to cut down on the pounding and it would actually make the hull stiffer and ride a lot better.

    As to building, the way to build this is to set up your framing upside down and then put the bottom on it, and the flip it over and do the decking.
     
  10. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Resp: Great thought, This is acceptable for the use and purpose, i am comfortable in that. I’m not looking for speed rather than its functionality and I’d be happy with 20-30 mph.

    Resp: Absolutely agree and planned on after the hull was glassed. Reason being an add on in my mind is that would be a wear item and that way the will be secondary to the hull and cane replaced without affecting the initial hull core.

    Resp: I will check that out.


    Resp. Could you sketch what your explaining. Thanks
     
  11. Yellowjacket
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    Yellowjacket Senior Member

    Just look at the "Diablo", it has a flat section in the middle of the bottom and outside of that the edges are angled up probably about 15 degrees unil you get to the sides. In your case the middle flat section would be four feet wide and the outside angled up parts of the bottom would be two feet wide on each side of the flat bottom section. Here is a link to the plans for the "Diablo Grande", which is a bit smaller in beam than what you're thinking about but be similar. You don't need to too much angle if you want to keep the draft really shallow, something like 10 degrees of deadrise would be fine. But really, in my experience a single runner on the bottom like a 1x2 isn't going to keep you from just skidding, you need more than that. Most boats roll into the turn and in that case a small stringer on the bottom will do it. But for a flat bottom it takes more skeg than that or you'll just skid like crazy, even at 25 or 30 mph.

    Diablo Grande – 18′-0″ x 6′-3″ – H.H. Payson & Company https://instantboats.com/product/diablo-grande-18-0-x-6-3/
     
  12. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Thanks yellow jacket. I set up some cheap Luen today and started doing some line drawings for the bottom section.

    I need some help before moving forward on the decision for the dead rise.

    I’m thinking I will need to inset the motor board area as such as,
    981373D4-9978-4233-B25A-E51688B844A2.jpeg
    (Above is a borrowed picture for an example of the motor well as per my question)

    On the hull I started to think about a couple things today while mocking up so cheap luen. Would it be possible to build two box hulls and have the center section become the bridge between the two.
    4D4CCF9A-6738-43B2-8346-9253DB8DE703.jpeg
    My thoughts are this might do two things,
    1. Create clean water for prop or jet drive as well as suction for jumping up in shallow water
    2. Combat the issues with handling in a turn. I could also add the skeggs, day two each side.

    Can you give you thought on this?
     

    Attached Files:

  13. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Another thought on the inset transom/motor board is it would allow me to build a box frame in the aft section creating two things,
    1. Support for the transom
    2. Possible addition storage and/or hull access, bilge pumps, rigging chases ect.
     
  14. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Thoughts on the hull sides
    46EEC2B3-8A75-489B-B5A4-6BE60CDD0E89.jpeg
     

  15. Aransas Flats Rat
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    Aransas Flats Rat Senior Member

    Here are a couple pictures that I hope will bring some light to what I am asking. Also please understand I am not changing my mind or trying to be all over the place just trying to do it right the first time. I want and respect you guys input and I am hear to learn and hopefully a few others will to.

    Bottom view (2nd hull option)
    F6A66A81-DA8C-4AA2-B534-5525B2E78B8C.jpeg 89BA6C58-D04A-4D4A-A984-EC59E636E2CB.jpeg
    Is there any major issues to do this in stitch and glue?

    Thoughts on possible stringers and framing.

    E2C66582-30B0-4656-85DE-C8E40113FE4C.jpeg
    Again I borrowed this pic from a previous project.

    If this is all to much to figure and will effect the integrity of the hull it’s know big deal just a thought. Thanks so much for your reply’s.
     
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