Also I have updated my pages on boatbuiding, restoration and repair methods.
For a long time now we have been fans of eliminating permanent fastenings in boats. We use plasterboard/drywall screws to hold the parts of the boat together until the glue sets up then remove them.
There are several good reasons.
1/ Fastenings always act as a potential way for water to get from one part of the structure to another. With epoxy construction there is always a waterproof glueline between the parts that make up the boat – but a fastener will always pierce that glueline.
2/ Often you launch a new boat but after a few years you can see the outlines of the fasteners – they can even crack the paint sometimes which allows water to penetrate the structure.
3/ The reason we are looking at in this article is that having no fastenings make it really easy to remove large parts of boat with high speed tools like routers, powerplanes and circular saws without the risk of hitting a fastening with them and risk damaging the blade the timber around the fastener or the operator.
We built our $350 OZ PDRacers out of a really terrible quality hardwood ply – not only was it brittle but it had significant interior voids with the result that Peter put his foot through the bottom – he doesn’t have my catlike agility!
We learned our lesson and specified a slightly thicker plywood for the bottom of the boats in the plans – remember that we were experimenting at this stage to make sure that the whole thing worked. In the end there were three changes we incorporated in the plans. A thicker bottom, a reduction in the height of the boat to give more room on the ply sheets and a stiffer mast. All of these details were included into the first plans we produced – the Mk2 OZ PDRacer.
I used the methods in this pictorial to repair the bottom of one boat overnight then the other boat the following night. That way there was at least one boat to sail all the time!!!
The bottom of the boat was completely removed by router. The router was set to the same depth as the plywood thickness. I then worked over all the frames and the remains of the bottom just fell to the floor.
I used the wet on wet method to fully coat the inside face of the replacement bottom then glued it in place.
One of these two boats went on to become the one that holds the world speed record for Puddle Duck Racers – 9.2mph. They have also travelled around 2500km on their trailer.