A ukulele that fits through a kayak hatch? Do they even sell such a thing? Especially in my favorite baritone uke scale length?
No idea, actually. Didn't even check. Why would I do that when it might offer a convincing reason to just buy one instead of building my own? Where would be the fun in that? Sorry, but that's just not the way I roll.
Also, I got my paws on a nice chunk of fat 5/4 american black cherry lumber to use, Prunus serotina itself. A very pleasant wood to work with indeed, both looking and smelling nice. I'm pretty sure it was destined from the start to become a travel-sized baritone ukulele.
I used the basic concept of the Martin Backpacker guitar where you saw out the neck and body out of basically one big stick. You do most of the shaping of the neck and headstock while it's still a solid stick that you can handily clamp into a vise. For the hollow body, I marked and cut outside the lines, and then used a spokeshave and plane to thin the sides down to where they seemed flexible enough to spread the way I wanted them to.
The ends are spread apart with a bit of stick sawn from the chunk I had cut out of the middle, so it would be the same height and all. I cut the ends to a consistent angle, and then sawed it into a nice arc. The ends were left thicker to act as a bit of integral blocking, and to leave room to thoroughly round over the corners with a rasp. Don't want your kayaking ukulele to have any sharp corners that could chafe on your drybags, you know.
The back and the top were harder to source suitable lumber for. After a bit of investigation though, I realised that lots of cheap ukuleles use nothing other than thin plywood for this, and I had some decent-enough pieces on hand already, some 2mm meranti-ish stuff that seemed resonant enough when i tapped on it. Certainly, it was no worse and probably better than the plywood on some of the cigar box guitars I've built. Plus, like I said, I already had some. With the back glued-on (complete with a brace installed) the whole thing suddenly got totally stiff and rigid. The holesaw on the bench there was for cutting out the soundhole. I had to check my layout while I could still see inside.