Winter/Spring 2007 - I've been exploring the coastline a bit recently, especially around the mouth of the river Hamble in Southampton Water (UK) - and It suddenly struck me that this river, several miles upstream, runs almost right past my door...
So... why not build a boat? Plop it in the water and sail/row/paddle it all the way down to the mouth of the river, then back up again, I guess.
Sounds almost too easy. That'll probably be because, not having done anything quite like this before, I haven't really much idea what I'm talking about, but it's going to be fun learning.
So what kind of a boat?
Well, the river up near Botley village, where I live, is navigable by small boats, but it's probably a bit too twisty and narrow in places for a rear-facing rowing boat, especially attempting to go upstream, and anyway, I want to be facing forwards, so it needs to be some kind of canoe/kayak, or something along those lines.
Initial searches took me quite quickly to the very interesting website of a guy called Hannu Vartiala - who is very clearly an experienced and accomplished builder of small boats.
'One Sheet Boats'?
I'm intrigued by the idea that a usable boat can be made from a single 8x4 sheet of plywood - I really like the simple construction of Hannu's Prism Boat - to which he has fitted oars, but I think could alternatively be used with a double kayak paddle.
But I'm just a tiny bit concerned about the low, flat ends of the Prism Boat, and anyway, I want to build something at least slightly original - in at the deep end (pun intended) of boat design, although it still needs to be kept very simple.
My boat design
I took the basic idea of from the Prism - joining identical strips of ply together to make a basic boat shape, but instead of three planks, each 16 inches wide, I've gone for six planks, each 8 inches wide:
-This changes the shape of the boat quite significantly - it turns from a flat-bottomed, flare-sided shape (which I understand is called a 'dory') into a rounded bottom, with sides that are more or less vertical at their top edge. This might not be entirely an improvement in terms of stability, but let's run with it and see what happens.
Changing the construction in this way didn't have any effect on the flat ends - so I have also added a couple of sections - this is mostly to stop the thing getting swamped by small waves (which might not be as big a risk as I fear), but also for aesthetics - I think my design looks nice - as I hope the pictures further down will demonstrate. Anyway, I end up with an exploded view that looks a bit like this:
Experiments
I built a couple of twelfth scale card models; the green one is the original prism design, the red one is my design:
I've also added small decks at either end - mostly for structural rigidity - I think I'll actually end up with what amounts to a fat canoe.
Starting the build
21 May 2007: I have nearly all of the materials now and I've cut out a template so that I can mark my ply to get all of the sections the same shape. I need to make a couple of sawhorses to work on, and my garage/workshop seems to have filled up with family junk again. I need to clear that out before I can start cutting.
22 May 2007: I made myself a couple of sawhorses(below) out of OSB that I had lying around - to make it easier to support the big ply sheets for cutting - they're the same height as my folding workbench and when inverted, they'll be able to support the hull of the boat so I can work on the inside without it rolling about
I've also made an MDF template for marking out all of the segments to the same size and shape.
23 May 2007: Marked up the boards today (above right) and cut them out...
They still need trimming up a bit and the shoulders need rounding off, then I need to drill them for stitching and the build can begin!
03 June 2007: Trimmed up the panels today - I was pleasantly surprised at how little difference there was between them - I had been expecting some of them to have cut out a bit wonky, but they were all the same to within a millimetre or so.
Then I clamped them together and rounded off the shoulders with my electric planer (I started with the hand plane, but it was too hard) - not the ideal tool for working with plywood, but the blades are new and sharp and I set the cut depth very shallow and it was fine.
So I now have the twelve sections trimmed and ready for assembly - the next few jobs are:
- Cut and trim the four wedge-shaped extra panels
- Drill the stitching holes
- Glue (butt join) the sections together in pairs to make boat-length panels.
08 June 2007: I've cut out the extra panels today (see above right)
Time to drill the stitching holes, so I made myself a little wooden jig to ensure they would be evenly-spaced
It's just a piece of wood with two holes in it, about four and a half inches apart and the same distance in from the edge - one hole has a masonry nail pushed through it, so the first hole is drilled with the nail hard up against the end of the section, then the nail is dropped into the freshly-drilled hole and the jig can be brought alongside the edge again to drill the next hole and so on, at precise intervals.
Both pieces to be joined (marked with the same letter) are clamped face to face and drilled at once, so the stitches should line up precisely in adjoining sections.
Drilling the stitching holes for the four extra panels was interesting, because the curvature of the two pieces is not identical - so I had to get the ends aligned, drill the first hole, then use the nail in the jig to keep everything in register while I rotated the pieces so that they were both flush-edged with the jig, ready for the next hole.
Just need to assemble and glue the butt joints, then it will very quickly start to look like an actual boat...
09 June 2007: I glued three pairs of sections end to end and secured the joints with ply reinforcement. I used nearly all my clamps, plus an assortment of paint pots to keep it all pressed down until the epoxy cures.
10 June 2007: The glue has cured and the joints look pretty good
The epoxy on the outside - where it was pressed against the polythene - has formed a perfectly flat smooth joint which will hardly require any sanding. The darker colour of the glued timbers indicates that the epoxy has 'wet' the wood fibres well - this means it's soaked in and the bond should be all the stronger, as it comprises the glue and to wood together.
I've glued up the last three pairs of panels today and because the weather has been exceptionally warm, the epoxy cured in a couple of hours.
Next job: begin stitching.
Now it gets exciting - see the next page for details...
