Tuesday, 6 March 2012

A pleasant distraction

Clearly, fixing up the coachroof is a major job, but not something I am even going to attempt until the weather improves a great deal. For now, best not to think about it too hard.

Some exercise has helped my back problem, but lying around twisting this way and that, I realised that doing something like lifting an outboard onto the back of a dinghy could be just the sort of thing to put me out of action for a good long while. I'd be much better off with a dinghy that rows well. I'd be getting the right kind of exercise to strengthen my back, and there'd be one less noisy outboard to feed, maintain, and keep secure.

A dinghy that rows well is long, too long to fit on my boat. So I figured a nesting dinghy would be best, one that comes apart, with one part stored inside the other.

The platform at the back of the boat is a metre wide. It could store a dinghy, but some of it would be hanging over the back. I think that would be fine for short journeys, day hops, trips in nice weather, but where there was a chance of heavy weather, I'd prefer the dinghy stored in the cockpit where the weight is more central. I'd have to leave room to walk around it fore and aft, but that leaves me 6 feet or so. With a 5' front section, I could have a 10-11' dinghy.

For the dinghy to fit just where I want to store it, and for it to be as big as possible within that space, I'd have to design it myself. A stitch and glue job would be nice and light, and I could design it to be as commodious as possible, so as to allow for rowing with 2-3 other people in it.

The free hull design program here was a great help. I imported the curves it produced into another CAD program, and saw that the curves weren't that even. I smoothed them out some more, and generated the numbers that would allow me to layout the panels. That was fun. My first boat design.

First I made templates using wallpaper, then laid them out on some 6mm ply (poplar core, nice and light):

Cut out two floor sections and stitched down the centre of the floor with wire:

Open the two parts out:

Add a side and the stern:

As I was working alone, I needed to use parcel tape to hold the parts roughly in position, so that I could stitch them together with wire. You can see the butt block on the side - a piece of scrap ply I've used to join the panels together where. I used a little bead of polyurethane glue for this so that I can remove the butt blocks once I have finished epoxying the boat and added the rub rail. The join is right where the boat will be separated into two parts.

Here's the rest of the parts stitched together:

Perspective seems to make the bow oddly too big, but in real life, it's exactly as I'd planned on the computer. Very satisfying. Assembly took just a morning!

Here's a bulkhead I added where I will saw the boat in two later. I've made two bulkheads, and joined them together with some corrugated cardboard. This will allow me to saw through nice and easy with a hand saw:

This pleasant work was quite a contrast to messing with wet foam and delamination down the cat on the river. It's occurred to me that if I find more delamination, one possibility it to use a grinder to chop off the whole of the coachroof, and transport it to the workshop where I can sort it all out without being interrupted by the weather.

Dinghy building seems like an escape from the more serious issues but planning the work according to the weather feels like a more seaman-like approach than battling on!

If anyone is interested in the plans for this boat, here are the plans in an A4 pdf file. 

The dinghy is 3177mm long and 1220mm wide at it's widest. You can make it with 3 8 x 4 sheets of ply.

You may want to wait till I publish a photo of the boat on the water first though!

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