Plywood/glass Jon Boat idea

Discussion in 'Boat Design' started by Kevin Miller, Aug 17, 2024.

  1. Kevin Miller
    Joined: Aug 2024
    Posts: 7
    Likes: 2, Points: 3
    Location: Georgia, USA

    Kevin Miller Junior Member

    Hi. I’m Kevin. Utter new guy. I’ve been planning a 13.5’ flat nosed, flat bottom basic Jon boat to build in glass over plywood this winter. I have questions. Plans Attached
    1- is there a critical distance from the bow I should begin the upward curve of the bottom toward the bow?
    2- Is a 14* angle from the bottom to the gunnel sufficient? I feel it is a bit too square.
    Thank you for any and all advice. IMG_3282.jpeg IMG_3283.jpeg IMG_3286.jpeg IMG_3285.jpeg IMG_3284.jpeg IMG_3281.jpeg
     
  2. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    Hi Kevin, welcome to the Forum.

    Nice drawings (not plans).

    1. Probably, but it depends.
    2. Hmmm... First off, it's not 14 degrees, it's 104* from the bottom and 14* off vertical.
    (2 cont'd) It may or may not be too "square".

    Very hard to know with so many unknown variables: speed, seas, travel distances, loading, engine size, operating weather, etc, etc, etc.

    Best advice I can give you is search for a sound, used boat that fits your needs (SOR).
    Preferably one with a good trailer.

    Failing that, the next best advice would be to build from a proven plan that meets your SOR.

    And if neither of those two options float-your-boat, then my final words of advice, and thanks for asking,
    would be to triple all your time expectations and then double that as to effort, money, grief, and time expected
    to complete your design and build.

    BB
     
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  3. Kevin Miller
    Joined: Aug 2024
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    Location: Georgia, USA

    Kevin Miller Junior Member

    Thanks for the reply and advice. I’m keenly determined to build, so buying fails the point. I’ll certainly take the time and effort estimate you offer into account.
     
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  4. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    The side view shows the curve of the bottom beginning too far aft. Also the curve does not need to rise the 16 inches that it appears to do. If you leave it as shown on your drawings, there will be a problem with the weight that the front pedestal will support. The boat will tend to stand on its nose. The sides are higher than they need to be unless you anticipate having a ton of fish in the boat or you anticipate operating in rough water. Be aware that Jon boats are not the best suited for rough water work.

    Fourteen degrees is about right for the transom and alright for taper (flare) of the sides. That is a convenient angle because it is a ratio of one inch to four inches which makes for easy layout.

    It might be a good idea to look at Jon boats at your local boat dealers place or at the typical Jon wherever you find it. Would be advisable to use pretty much the same layout as the Jon boats that you see. There are about three zillion of them out there, mostly made of aluminum. No need to change the general layout of something that has proven itself so well. The Aussies and Brits have a pet name for them. They are "tinnies".

    You have done a good job of drawing a scale layout of the boat.
     
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  5. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell . . . _ _ _ . . . _ _ _

    No problem, but you did say:
    And I should have added that after all your hard work you may be disappointed with the outcome
    as it will be a one-off with unknown handling characteristics.
    But I do admire your tenacity.

    Best of luck with your designing and building.
    Keep us updated on your process and progress.
     
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  6. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

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  7. Kevin Miller
    Joined: Aug 2024
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    Location: Georgia, USA

    Kevin Miller Junior Member

    Thanks so much for taking the time to consider my ideas and offer your thoughts and expertise! I really appreciate it.
     
  8. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    What are your latest thoughts now Kevin, after reading ours posted above?
     
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  9. Kevin Miller
    Joined: Aug 2024
    Posts: 7
    Likes: 2, Points: 3
    Location: Georgia, USA

    Kevin Miller Junior Member

    Thank you for asking, @bajansailor. My first thought is gratitude for your (all) replies. Regarding practicality, I’m retired and all my kids are grown and moved on, so building a little boat is a long held dream of mine that I may now indulge. My lovely bride also asked why I don’t just buy one.
    I have seen videos of numerous boats built with “stitch and glue” or similar methods and I understand entirely what I’m getting myself into.
    Regarding design, I did indeed go out and look closely at a variety of jon boats before deciding on this basic shape. I then drew this up in about an hour one morning. My next examinations will include the liberal use of a tape measure. I like the idea of buying inexpensive plans to work from and the Duckworks boat is quite similar to what I want.
    My use for this vessel will be fishing local creeks and rivers in South Georgia in the U.S.; possibly local lakes, which is why I drew (not plans) a tall-ish hull.
    Truly the most valuable response to me (although, again, all are appreciated) was from @messabout who noticed my forward seat pedestal is drawn forward of the bottom hull rising toward the bow. I should have noticed that.
    All the responses to my questions have merit.
    I’m adding a photo of a “tinnie” aluminum boat that has a close profile to what I’m looking to create, and behold, (which is to say I just now noticed) there that forward seat is, aft of the bottom hull rising point!
    I’ve given myself until January 1, 2025 to finalize my drawings and begin laying out, so please continue offering any and all critiques of this project.
    KM
     

    Attached Files:

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  10. Kevin Miller
    Joined: Aug 2024
    Posts: 7
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    Location: Georgia, USA

    Kevin Miller Junior Member

    Per the above conversation, I’ve redrawn the boat: changed out the stern seat pedestal for a different seat idea, relocated the forward seat to aft of the hull rise point, started the hull rise about 18” farther forward.
     

    Attached Files:

  11. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    The angle of the bow seems regionally specific. Brand dependant you'll see steeper or shallower bows. Was told by a guy who pieces together welded flat bottom river boats that he has different slopes and start points. Villages off a river that has tons of low sloped gravel beaches prefer ones like the camo one you posted for getting in and out while beaching. The river systems with steeper cut banks like shorter more squared off noses than carry more buoyancy forward and support stepping up on the bank.

    Aside from that I have no specific thoughts.
     
  12. Kevin Miller
    Joined: Aug 2024
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    Location: Georgia, USA

    Kevin Miller Junior Member

  13. thundermountain
    Joined: Sep 2022
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    Location: Van Buren, Arkansas

    thundermountain Junior Member

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  14. Kevin Miller
    Joined: Aug 2024
    Posts: 7
    Likes: 2, Points: 3
    Location: Georgia, USA

    Kevin Miller Junior Member


  15. Cory
    Joined: Nov 2020
    Posts: 19
    Likes: 1, Points: 1
    Location: Sedro Woolly Washington

    Cory Junior Member

    Kevin

    Sides tilting out 20 degrees is within a half a degree of ultimate average of this style boat.

    62 inches back from bow if the boat is 4 ft wide is where the bottom starts to come up.
    If it is a narrower boat that distance becomes shorter.
    The narrowest 13.5 ft Jon boat I have had my hands on is 46.5 but in areas were there is no ripple on the water I have had people talk about super thin aluminum narrow low side Jon boats for one person to move in and out of the water with no boat ramp.
     
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