We had wanted a Galley Shelf over the sink of our 1985 Catalina 30 mk I, so I decided to build one. It is 3/4" A-A grade plywood I had around trimmed with pieces made from some white oak floor boards I also had around. The shelf hangs from a 1/4" screen door turnbuckle that I modified for the purpose. I made an insert out of some 1/4" fibreglass I also had in the shop and put the pegs that hold the dishes in it. This way I can change it out later if we decide to change dishes or purposes without having holes in the shelf itself.
The deck is not parallel to the galley counter, so there is a tapered filler piece. This means the screws holding up that end are of different lengths. Be careful you do not use too long a screw or you will penetrate to the outside. This shelf only comes out as far as the sink faucet so access to everything is unhampered. We added an LED strip light under the shelf wired into the galley light. This helps with illuminating the galley counter a lot.
The deck is not parallel to the galley counter, so there is a tapered filler piece. This means the screws holding up that end are of different lengths. Be careful you do not use too long a screw or you will penetrate to the outside. This shelf only comes out as far as the sink faucet so access to everything is unhampered. We added an LED strip light under the shelf wired into the galley light. This helps with illuminating the galley counter a lot.