Stitch and Glue Ply

Stitch and Glue Ply

This is normally restricted to cartop and trailable boats, where ply thickness of up to around 6 mm can be used. For the smaller boats the panels are plain ply. Larger boats can be built with the panels in thin ply, then GRP sheathing applied both internally and externally, generating a sandwich construction. This technique is regarded as giving faster and less demanding construction than ply on frame. This will be because framing is not required (or isolated framing is fitted to the built hull shell), and for the larger sizes the shaping and fitting of thick ply is avoided.

Many recent applications of ply stitch and glue techniques have been for timber epoxy construction, or as the basis for GRP/ply sandwich construction. This latter allows thicker panels to be built, to suit larger boats.

Normally the ply panels are cut out to their installed shapes, and progressively pulled together along their longitudinal seams (stem/keel and chines), with copper wire (or recently plastic cable ties) through holes. This progressively generates and controls the hull shape, which can be adjusted to some extent prior to the fitting of framing. A basket frame can be used to help generate the shape, and support the hull (right way up) during construction.

Flared bow shapes can be generated by making a series of slender V cuts longitudinally in the topside panels. These will generate near-flat joints.

Seams are then filled and glassed internally.  The copper wire are then trimmed back externally, and the seams  are glassed externally. External and internal faces are glassed as required. Gunwales, internal framing etc are added as required, and the outer and interior surfaces smoothed and then coated as required.

A Plywood Stitch and Glue Dinghy – Hull Shape

A Plywood Stitch and Glue Dinghy – Panels

 

Stitch and Glue Joints

 

Convert a Design to Stitch and Glue

If there is a design you would like to build, but it lacks the panel shape information, all is not lost. (I am assuming you have some familiarity with the stitch and glue technique and with boat hull shapes.)  I haven’t tried this, so at ths stage you are on your own.

  1. Get a copy of 3DBoatDesign software ($50 nominal), install it, and get some familiarity with it.
  2. Enter the hull shape of your chosen design into 3DBoatDesign.
  3. Adjust your hull shape to achieve fully developable surfaces. (This is a feature of 3DBoatDesign.)
  4. Output the shapes of the hull panels from 3DBoatDesign. I will offer procedure on this when I have tried this).
  5. Mark out the panel shapes onto the ply sheets. You are on your own for positioning the ply panel butts and the nesting.
  6. Cut out the ply panels, and proceed with building your boat.
  • Go to Boat Design Software page for 3DBoatDesign information – click here

 

 Tutorial

There is a well illustrated tutorial on Stitch and Glue construction  under “Tech Support” on the Bateau website. This is well worth a viewing if you are considering the technique. Click here to go to the Bateau website.

 

  • Go to Stitch and Glue Ply Blog page – click here

 

The Major Plan Supplier  Bateau  (E-Boat Inc) has an extensive range of boats, all using this technique.

  • Go to Bateau page – click here
  • Go the Bateau website – click here

 

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