Help with scooter boat design

Discussion in 'Boat Design' started by Aransas Flats Rat, Jan 22, 2020.

  1. Aransas Flats Rat
    Joined: Sep 2018
    Posts: 188
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    Location: Florida

    Aransas Flats Rat Senior Member

    Hello all my Name is Capt. Travis I currently live in Florida and I am wanting to build a Texas style Scooter (basically a platform). I have built three boats from a set of plans and done a total gut and rebuild as well, I am familiar with stitch and glue type builds as well as general repairs.

    I would like to build a platform type boat that would enable me to access very shallow water to gig flounder, I’m not so concerned about handling at speed as the boat will mainly be used at an idle or short runs getting from one bank to the other. I have done several searches and have found nothing similar to my needs.

    Boat description:
    16’
    7-8’ wide (floatation/stability)
    Shallow draft 5”-10” at rest
    Forward rake
    Pocket Tunnel
    Main power: outboard engine
    Second source: 18hp Honda with 3 blade propeller (air motor)

    Want boat as light as possible and needs to be nothing fancy but yet functional.

    Would like to use stitch and glue glass over ply method if applicable.

    Please see pics for reference of desired design.

    Thank you in advance for your time, comments as well as input.
     

    Attached Files:

  2. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Either a catamaran hull or a Sea Sled hull could work well in this situation.
    What diameter prop are you putting on the "air motor"?
     
  3. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Thanks bluebell,

    I looked at these designs and I would like something simple and flat bottomed, nothing fancy. This boat will have one purpose. I have a fishing boat.

    Will use an experimental synthetic 3 blade 36”
     
  4. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

  5. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    The design proposed seems simple and affordable to build I just don’t know how to get started.

    I’m thinking 4 4x8 sheets but joined and taped that would make a 16x8 sheet to start.

    Sheet thickness is one question? My thoughts are 3/8 or 9mm would be sufficient for the hull bottom and 1/2” for the pocket tunnel.

    Thinking side depths would be about 12” aft and tapper down at the curved bow.
     
  6. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Thanks bajansailor,

    Here is what I’m wanting. First pic is a gutted one without deck and stringers second pic is a completed one. These are 12’ I need one at least 16’

    I will use the air motor mainly, however not at speed but to simply move the boat forward at a slow idle. For best example like a trolling motor.
     

    Attached Files:

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  7. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    This should help with visualization.
     

    Attached Files:

  8. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    I think it would be very similar to an airboat hull but with very low sheer, reason for no sides is the ability to freely step in and out of the boat as well as flipping flounder into fish box on deck.

    The main area I am lacking is the knowledge of how to design and figuring out the displacement factors.

    Should sides have a angle say at 15deg or should they be straight up and down.

    I would see at least 4-6 1/2” thick stringers egg crated and then foam filled.

    Two layers 1/2” laminated for transom?

    Lol I need a start off.
     
  9. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Here is what I have as per weight so far,

    40-50 hp 2 stroke
    190#
    Air motor/prop and stand
    150#
    25 gallon fuel tank
    150# full
    Three 12 volt deep cycle batteries
    204#
    mic. wire, lights rigging
    150#

    Total estimated rigging:
    844 lbs.
     
  10. Yellowjacket
    Joined: May 2009
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    Location: Landlocked...

    Yellowjacket Senior Member

    What you want is very similar to what we used to use as dive boats in south Florida when I was a kid. They were flat bottomed and we often had a clear plastic panel in the bottom so we could see down into the water. These boats were made out of 1/4 inch plywood that was laid over a frame of 1x2's. The areas where the two pieces of plywood where joined, (like down the middle of the hull) were 1x4's so the skins could be screwed into both pieces of plywood and the center spine also had a vertical 1x3 that was set vertically on edge to act as a backbone. The stringers were about a foot apart and the transom was a one inch plywood and the height was bigger than the main deck so the wake wouldn't wash over the top when you slowed down. IIRC the height of deck was about a foot and a half from the bottom and it was made out of 3/8 ply with framing to make it stiff enough to walk on. Overall it was pretty light and easy for us to move around. The decks stiffened the transom but there were some hatches and bins inside. I don't think you're going to find any plans for something like that, it's too much of a specialized thing.
     
  11. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Thanks Yellowjacket. That makes since. I was wanting to stay clear of the framing and screws, but use stitch and glue method, instead of framing use stringers and bulkheading (egg crate) bottom and side panels butt joined and taped, stingers offset joints by laminating two pieces of 1/4” ply. As you stated two sheets laminated 1/2” for transom/stern and braced with knees attached to stringers.

    I’m think the BOM is:

    Bottom: 4 4x8 1/4” thick
    Sides: 2 4x8 1/4” thick
    Stringers: 4 4x8 1/4”thick
    Deck: 4 4x8 3/8” thick

    Hoping someone times in on design.
     
  12. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    What he wants to make is a Texas Flats boat. They are essentially a flat bottom, flat topped barge (or scow) with a console and seat mounted on top, and a motor mount at the stern. see Dargel Boats https://dargelboats.net/boat-model-lines#16a15910-3ae0-4e5a-af49-c8b47217b064 Several companies in Texas make them for working the shallows on the Gulf Coast. They have to have an exemption from the US Coast Guard because they cannot meet the flotation and loading standards, not because they don't have enough, but because the tests are based on conventional boats with high sides, that you sit in, not on, and the flotation tests are based the same way. Anyway, he simply needs to build a long, wide, shallow box. Then fill it with foam.
     
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  13. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Thanks so much Ike, description is perfectly said.

    Just trying to get a starting point as there is no available plans.

    Questions:
    Bottom section:
    1. Is 1/4 marine ply sufficient for the bottom panels with a layer of 1708/Epoxy?

    I’ve seen guys subject to oysters and rocks use two layers of 1708 and they claim it’s somewhat bullet proof.

    Sides:
    1. Is 1/4 sufficient as well for the sides again one layer of 1708?

    Thanks
     
  14. Aransas Flats Rat
    Joined: Sep 2018
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    Location: Florida

    Aransas Flats Rat Senior Member

    Thoughts on assembly and design.

    1. Assemble bottom panels, figure out bow rake
    2. Make pattern of stringers from that
    3. Cut out trans frames
    4. Assemble stringers/frames and build on top of that.

    Option 2:

    Build two individual hulls and bridge them in the mid/tunnel section. I would assume this method would involve a much more complex framing system?


    I am still at a loss as I don’t have a degree and I have never designed a boat. I understand I am asking a lot and taking my own risk and except that 100%. This seems like a simple design would just appreciate some help getting there. Thanks
     

  15. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Have you seen this thread?
    Building a boat for Texas flats. https://www.boatdesign.net/threads/building-a-boat-for-texas-flats.54072/

    Post #4 by the legendary PAR sums it all up very well.
    In this post he refers to the TX 18 -
    Texas Sled 18 (TX18) - Study Plans https://bateau.com/studyplans/TX18_study.php?prod=TX18
    This has a sunken (slightly) cockpit - however I am sure that you could make it a completely flush deck as per your initial thoughts. And if it is completely flush deck, and filled with foam, then you could probably reduce the hull depth a bit if this is really an issue - although will a few inches of 'extra' freeboard really hinder your flounder catching ability?
    Having even a small rail or bulwark around the gunwhales will be appreciated the first time that a fish or an important tool slides (or is kicked accidentally) overboard.
     
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