The keelson is the long, thin, tapered panel which sits on top of the keel and connects it to the bottom panels of the hull.
It is a very simple component and manufacture was a piece of cake after the keel assembly!
Here is the keelson, with the two halves glued and clamped together on a saw horse.
And here is the cured puzzle joint, sanded smooth.
It was then tucked up in the workshop rafters, out of harm's way until required.