*cringe* This suggestion will prolly get me lynched -- either by traditionalist sailors or my fellow woodworking professionals....
How about composite decking products -- eg, Trex or TimberTech? Mills easily, doesn't rot, splinter, or warp. Not real expensive in small quantities. You'd have to leave expansion room, & it isn't especially structural. But it'd be my first choice of decking in a persistently wet environment. Could make your little pop-up table out of it, too.
(I love wood. Make my living with it. But it has its limitations, and marine environments .... not so good.)