Looking for input on boat.

Discussion in 'Boat Design' started by Crash5291, Jun 4, 2012.

  1. Crash5291
    Joined: Jun 2012
    Posts: 6
    Likes: 2, Points: 3, Legacy Rep: 10
    Location: Ontario, Canada

    Crash5291 Junior Member

    Hi all,

    Thanks for looking. I will try and answer a few questions i know will come up and hopefully it will make this easier.

    I make my living working on the St. Lawrence River in the heart of the 1000 Islands.

    Been around/driving boats all my life. This is my first attempt at building a boat though.

    My main worry is in the actual design of the boat.

    Its intended use is fishing, needing a shallow draft and decent stability.

    This will be a Plywood build with a layer of fiberglass to seal it all up.

    My questions are: (referencing attached picture)

    How stable will this design be?
    Thoughts on its tracking through the water?
    Thickness of materials to use for the outer sheathing should be?

    My thoughts are inner framing every 2 feet, with a pair of tie backs for the transom locking it to the last 2 frames or so

    I would like to make it stout enough to take a 25-30hp motor.

    The hull drawing i attached is one of 2 i have the second is just on paper right now.

    Attached is to be a 16' OAL 4' 4" beam top, 4'beam bottom.

    Second design is a 16' OAL with a 7' beam bottom and a 7' 4" beam top. with a custom cut center beam that will give a small skeg through its length to help tracking.

    So fellas What are your thoughts?

    Attached Files:

  2. Stumble
    Joined: Oct 2008
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    Location: New Orleans

    Stumble Senior Member


    I would ugly recommend going and either buying plans for your boat, or finding them for free.

    Something like the scrambler at Glen-L, or one of the powered drift boats seems to fit your plans, but will save you a ton of work, and since it doesn't appear that you have any design experience, will likely save you from a poor performing boat, months of headachs, and a lot of time and money spent on something you aren't happy with.

  3. rwatson
    Joined: Aug 2007
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    Location: Tasmania,Australia

    rwatson Senior Member

    Stumble has said it all - that design is very ordinary, and performance will be less than acceptable.

    All the questions you have on the materials ( scantlings ) will cause you a bunch of headaches - so get a proven design, and enjoy the building experience, and end up with a boat you can enjoy using or selling.
  4. PAR
    Joined: Nov 2003
    Posts: 19,128
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Crash, welcome to the forum. The usual set of questions are in order. Have you done a weight study? Where are your CG and CB located and their relationship to each other, etc., etc., etc. If you aren't able to answer these very basic questions, you're not at a point where designing your own boat is a wise thing to consider (no offense intended).

    There are countless jon boats of that general configuration available, with the engineering and hydrodynamic stuff already figured out. You can spend some time learning about engineering and yacht design, or you can just take Stumble's advice and get on with the project next week when the plans package arrives.
  5. mydauphin
    Joined: Apr 2007
    Posts: 2,161
    Likes: 53, Points: 48, Legacy Rep: 575
    Location: Florida

    mydauphin Senior Member

    Don't let the above guys get you down, they like to design things that work all the time. Takes the fun out of it. I have built a couple of boats like that before.
    I was surprised by...
    How much it cost by the time I finished, would have been cheaper to buy a old hull
    How slow it would go, it got heavier with time and had trouble planning
    How much it would pound in the surf, but was actually faster with a little headwind
    I also would not go to a 20+hp engine, 20 hp puts alot of stress on structure, you have to make sure it can handle it. You also need increase side height. Mine was 2 feet tall.
    I would think 15 hp is about all it would take.
    Tracking will suck even with skeg, it will travel at angle to the center depending on weight. That is problem with nearly flat boats.

    But I used it for years, and it more than paid for itself. It would carry 800 pound of weight and 2 people all over the bay. We used it for seawall repair and even to install piles.

  6. Crash5291
    Joined: Jun 2012
    Posts: 6
    Likes: 2, Points: 3, Legacy Rep: 10
    Location: Ontario, Canada

    Crash5291 Junior Member

    Hello all,

    Buying plans seems like the easy way out, and after a few failures i might give in but doubtful.

    I wondered about side height that's easy enough to adjust

    I have been looking for an old hull that is close to what i want but have not seen any in the last 6-7months of looking. i will continue looking that's a given.

    I don't mind the wander a flatboat has, and at times it can be fun.

    What i am after is the side to side stability that our 17' Carolina Skiff has, 2 men and tools one side working over the side with up to 80lbs of steel being held and it is stable and still tons of height from water to gunnel.

    I added in the slight V to the bottom on the thought of adding in tracking but not losing a lot of draft.

    On the back of my mind is build light and prove the design then i can just recreate it in metal.

    I hope to have time in the next few days to move the 2nd design from paper to computer.
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