Mine is rather complicated, but I'll try to describe. I wanted a big table for the cockpit, and when I measure the dimension and compared to both the gap between the settees and the cockpit seats, realized I could make one which folded in half for stowage but when unfoled would both serve as a table and drop between both the cockpit seats and the between the settees to permit both outside sleeping under the stars (with a rather large mosquito net hung over the boom, etc.) and inside across the cabin. For outside I move the cushions out, and for both I have a rollup, blowout camping pad which fits the gap just right.
Outside would only be an option at anchor in calm weather, so no need to worry about securing. Just needed to make sure side and end supports where proper. Am using a ubolt which replaced the rear cockpit locker hardware, which I also use to secure my lifeline. Cockpit hatches are secured internally with line running into the cabin to cleats. Have small platforms which insert also into the placements wherere the hardware for the side lockers used to be, and where the end meets the companionway, it is supported by a pair of cleats which are used to secure misc lines and jacklines.
Inside, I have a platform which normally is the base to the seat for the drop down nav table I built over the port-a-potti in the head (yannked all the fancy head hardware and hoses - port-a-potti there for the wife and kids only...). anyway, it has a gap in the board which fits the end of the table towards the galley and secures down through the hatch to the top of the old holding tank, now chain locker. Installed two thin 1" / 1" strips along the settees which hold small gear, lines via bungee cords etc. normally, but on which the platform rests when in use - platform secured down by same small lines crossing over the platform. The other end aft just rests in the top staor (with the other points secured, it's not going anywhere!).
For table, the underside has fold down legs with dowels which fit into the legs and extend to bridge the gaps when used as a table.
Am still tinkering a bit with it all - as you can tell I like to find at least two, sometimes three or four uses for the mods I do. Admittedly, one issue is stowage for it, as even folded in half it is a fairly large piece of "furniture." Thus far I've tried it secured it in the head and v-berth - not quite satisfied with either yet....
