I doubled up the thickness of the coaming as shown in the gray area illustrated at right.

The motorboard is laminated from several layers of plywood to 1.5" to 1.75" total thickness. The top of the board should extend about 1" above the coaming.

The board is set against 2" wide hardwood cleats which are securely screwed and glued to the coaming.

A hardwood brace is located on the forward face of the board, about 6" from the top. Since this piece slants in towards the motorboard, you will want to cut a limber hole in the brace so that water does not collect here.

At this point, the space created by the transom, coaming extensions and motorboard will not have a bottom. I originally left mine this way, but regretted it. Too much water entered the boat this way. I later added a bottom, and you should too.