I decided not to build the gallows and instead opted to construct my own design of a stainless steel stand which is easily removed by pulling out two clips held in by bungee cord and lifting it out. It takes about 20 seconds to fit or remove. Here are some pictures
There is a small plate with a pin screwed to the floor for the post to locate on.
Stabilizing brackets attach to pins on metal angle brackets screwed into the transom. Not too bad looking when the post is removed. You can also see the bungy cord and clips which attach the brackets to the fixed pins.
At the top I made a stainless V shape and used some creative knot tying to form a soft cradle.
The Stainless pole looks quite elegant and is very strong. I have just completed a 1000 km round trip with no problems with my design. My wife helped me with some sewing to make the cover for the mast and sails etc. We also made a cover to keep rain out of the not so watertight hatch doors when driving or parked.
I included a hook on the post that secures the tiller during road travel
Another view of the soft cradle at the top.
My main motivation to build this was that I intend to use the boat for occasional fishing outings and so thought that the gallows as designed would get in the way.
Well it works for me.