It took a lot of planning and preparation for this step: joining the two halves of the PRT tightly but still able to be easily removed for storage and transport.
My solution was to use 4 inch lag bolts with thin nuts on the outside of the smaller section. This creates permanent pegs for the front half to slide onto.
First I created a notch in the board a bit bigger and deeper than the nut. Through the center of that hole I drilled all the way through the board. You can kind of see the result in this photo.
Once the first board was drilled, I lined up both halves and screwed them together. I continued the holes through the other support.
I then unscrewed the sections and pulled them apart. I then proceeded to install the lag bolts and check for a proper fit. Overall it worked out pretty good. Here is the final result.
Now that this is done I can proceed to panel the rest of the hull and work on a card stock stand-in for the pilot house.