Here are some shots of the depth sounder bracket I made. It was made out of scrap stainless steel (lid of a broken alcohol stove), and some scrounged teak (broken autohelm bracket).
It is basically an oval shaped piece of stainless with 3 holes drilled in the bottom an one in the top. I bent the top and bottom 90 degrees. It is mounted on a piece of teak, which is attached to the rear bulkhead, just off to the side of the companionway. The arm itself is a piece of teak, with stainless strips on the top and bottom. I used some threaded stainless rod as the hinge point - it goes through the top of the bracket, the arm, and then the bottom. There is a little vertical slack in this. On the bottom of the arm is a pin - this pin fits in the 2 holes in the bottom to lock it in place (one for the folded in position, one for the extended out position).
Here are some photos:
It is a pretty simple design, and could easily be adapted to better suit a particular boat, or the material on hand. It would have looked really good with brass/bronze instead of stainless steel, but that would have required constant polishing. Aluminum would have also made a good choice. Since the wood is inside your boat most the time, you could use whatever type of wood you have inside your boat, or you could use spruce/pine/fir or whatever and paint it.
