I've been building the cabinet to stack the refrigerator, microwave, and a roll-out trash receptacle. It will connect to the kitchen cabinet when it is fabricated...
The first phase of this was to build a robust framework to support the refrigerator and microwave on top. We wanted to elevate the refrigerator so we wouldn't have to bend over to get things from the bottom. The entire structure is screwed to the structure of the boat. Debbie had an idea to build-in a roll-out solid waste receptacle, so here it is. The photo above shows it with the door test fitted...
Jumping ahead, here's the 2nd and 3rd levels fabricated, the refrigerator and microwave installed, and the outer luan covering installed on the structure. The last picture is after all of the joints were caulked and awaiting paint. The lower section is not covered, as the kitchen cabinet will be fabricated and attached on the lower side, so no covering is needed there.