Planning Stage

Those are spritsails on the dory lollygagging across the background, not everybody had them. At least the guys in front are getting some fish. All that crap in the boat and there's still room for a ton of codfish.

These guys have a sprit sail rolled up on the mast laying alongside the oarsmen, but there doesn't seem to be that much wind right at the moment. Very impressive mittens, among the many bits of gear worth studying in this photograph.

I get these ideas, see, and they fascinate me somehow, bordering on obsession. Riding the bus, falling asleep, having coffee, lurking on Reddit, my little mind will not shut up about it but I do make progress sometimes and the idea gradually works itself into a recognizable shape. When I am lucky, that is, lucky and honest with myself.
I have never actually seen a working Grand Banks Dory with spritsail complete. I am developing this thing based on what I know from the small craft I have seen and the book by Pete Culler, Skiffs and Schooners kind of the bible for the theory of the thing with a lot of nice drawings.
But not of the "partners", the construct that holds up the mast. In his drawings it is just a hole in a thwart and a block on the floor. The actual ins and outs of mast support aren't mentioned.
I won't have a thwart handy.
There are three in the dory, 2x8 cedar, just planks with a taper on the tips and a notch to locate them at a particular rib (frame) to sit on and row or if you are lucky, to sit on while somebdy else rows. They fit on the third, fourth and fifth frames.
I want the mast to go on the second frame from the bow.

I think I will have only one of the little arches and the horizontal breadboard type slab wiith the hole in it. But this is the idea that solved the most of the problems.

SO the necessity turned my mind to possible solutions, and I considered one thing and another, ways you could get a cross piece on there with a place to secure the mast. The block on the floor is a given as long as it spans enough width to spread the force across enough planks to even out the load.
I made a little drawing, which is not, I should warn you, an architectural plan, but a concept sketch. I liked it.
It seemed to me that the seat-plank type deal wasn't very high in the boat and that there might be too much leverage against it if the wind started to cook like it hopefully does, after all I have a reefing band and if you reef your sail the wind is cooking for sure.
Another trip over to the salvage yard, where they soaked me 16 bucks for a slab of old  growth 2x8, which I brought home on the bus. People looked, but nobody laughed.

I'm pretty good at working things down gradually enough to make a snug fit. I made a big bedstead once that had no fastenings or glue. You assembled it with a mallet. Anywaythis bracket will be easy enough to make, with notches and tabs and insert part B into slot A type thing.

 Later on the drawings and planning changed from the support to how to hold  that up in some kind of way that would allow the whole thing to come off and stow away.

This is the part that kept me obsessed with the subject, but I think you could make part of this bracket rotate like the latch on the door Almanzo made for Laura and Ma's Little House on the Prairie.

Some time soon we will have a nice discussion about how this shit actually corresponds with reality...