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Enclosing the Pontoon

A project log for A Plywood Canoe

I built this canoe 10 years ago. It was fun but various design flaws has limited it use. This project is about a salvaging the canoe.

agp.cooperagp.cooper 03/15/2017 at 07:280 Comments

Enclosing the Pontoon

This has been a difficult problem to solve. You cannot just fibreglass tape the outside seams as it will leak. Not good. Here is an ideal join (source unknown):

Note how the yellow filler seals the joint.

One option is to cut holes in the last plank/panel in order to gain access to the inside seam and then patch the holes when done. I did this once and I can say it is still not that easy to tape the inside seam and patch a curved (stressed) panel afterwards.

Another option is to add a chine log/stringer/batten and screw/glue the last panel after bevelling as per this example (source unknown):

Image result for kayak chine stringer

In the end I decide to "lap-strake" the last panel. Here is the unfolded panels (one side only):

The magenta panel is a copy of the blue (top) panel but shifted 50 mm up and trimmed to the blue panel. Instead of using the blue (top) panel, the magenta panel is used instead. After all the inside seams are done, the blue (top) panel is glued/screwed over the magenta panel.

The main problem is that the panels do not fit on a half standard plywood sheet (i.e. the black box) so I will have to shrink the pontoon a little

Updates to the MiniKayakTable Spreadsheet

More updates to the spreadsheet for the above closure method and the inclusion of some DXF export code. The DXF file is as simple as can be but I know not all CAD programs will not be able to read it. As they say: "Not my problem!" as it works with DeltaCad:

I need to get the data into DeltaCad so I can re-export it for laser cutting, if I decide to build a model. I originally intended to migrate the excel macro to DeltaCad once I had "ironed out" the bugs. I still may if I can workout how to add a table input in DeltaCad.

Here is the central pontoon bulkhead:

AlanX

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