Transition joint or full length butt joint

Discussion in 'Wooden Boat Building and Restoration' started by unseen wombat, Jul 7, 2009.

?

How did you join the side panels to the bottom panels on your boat?

  1. With a transition joint near the stem

    1 vote(s)
    33.3%
  2. Butt joint all the way down

    2 vote(s)
    66.7%
  1. Projectus
    Joined: Mar 2017
    Posts: 3
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    Location: Wisconsin

    Projectus New Member

    Hello PAR,
    I've been itching to build something all winter, and I've always wanted to build a small boat, mostly for fishing in spots I've otherwise only been able to access with a kayak, so I started some research a week ago.

    I watched Sam Devlin's Polliwog video several times, and I'm just having a hard time with the reason for the transition notches cut near the bow. One of the mysteries to me, is that it appears to be a nice butt joint along the notch section, and then the side panel appears to overlap/overhang the chine, aft to the transom. If planing away all that overhanging plywood is done, I can't picture what material is left!

    I know I'm missing something here, many, many things most likely, but as I look around for plans and methods, I'm taking this particular mystery into heavy consideration.

    I've always drawn my own plans for projects, but I know too little about building boats to attempt drawing up my own.

    I should begin with what I am hoping to build. I'd like something small - about 8-12 feet. I don't mind scarfing. The stitch and glue method intrigues me more than building frames does. And, I've seen a few plans that use neither. Ideally, I'd like to slide it into the bed of my truck (6-foot bed), and I'd like to be able to use a 36-lb thrust electric trolling motor, or a very old Neptune Mighty Mite motor that still runs. I think it's jus 3hp. I think I'd better be able to row it too...

    It will be used for fishing out-of-the-way lakes in Wisconsin. And for satisfying my instinctive urge to build stuff. If I enjoy it, and I think I will, I'd eventually like to move on to something larger.
    I appreciate the response,
    Dan
     
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    [​IMG]

    This shows two angled joints, the bottom two typical of what you'd find aft of the "transition" and the top one forward.You can see the plywood edges ride against each other differently, which is why there needs to be a transition. In reality you can precisely make this or simply fake it. On the faked joint, you just fill the gaps with goo and fabric, as under putty and paint, who's to know. The fabric and epoxy will take the place of any missing plywood and these areas need to be rounded over heavily anyway, so the fabric can lay down neatly.
     
  3. Projectus
    Joined: Mar 2017
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Wisconsin

    Projectus New Member

    I really appreciate the responses, thanks. Hopefully after I complete a project, I can contribute more than just questions.
    The graphic appears to show a top view of two pieces of plywood meeting each other, but more in a way of meeting at a corner. But a butt joint of a side panel sitting atop the bottom panel (chine?) long edge to long edge, doesn't appear to be two sheets of ply joining the way the graphic shows.
    The question I have, is not so much why the transition notch, I can live with that, but what happens after the notch. I'll try attaching some screen shots from Devlin's video. The apparent non-joining of the remainder of the side, aft, bugs me.
    Maybe after that joint is planed down, the remaining plywood edge will be okay because fiberglass cloth will be applied later.
     

    Attached Files:

    Last edited: Mar 27, 2017

  4. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Again, this technique is left over from older build methods, as a way of making an overlapping joint turn into a butt joint, in the forward portions of most hulls. The angle changes so much that you need to maintain alignment. In reality, it's unnecessary on taped seam builds. When you reach this point in the build, you can simply use a belt sander or plane, to whack off the offending area. Forward of the transition, the end grain will face each other, while aft of the transition the end grain will be over lapped by the other planking panel. It doesn't need to be neat or clean, just aligned properly. Once the thickened epoxy fills the gaps and fabrics are applied, the interior of the joint becomes invisible and essentially irrelevant, both structurally and aesthetically, assuming good prep and bonding techniques.
     
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