Water doesn't get to that area very much. Maybe during wash down, and I just don't spray it hard. It's really a good place for weights, outrigger tackle, drain plugs, rubber bands, etc. Not a good place for hooks and lures, it's outside, even more moisture because it's outside would just rust everything.
Make it entirely out of wood, don't use drawer rail hardware, that would just rust too. I took all the drawers out, West System epoxied the wood on all sides, and epoxy painted them when I redid the wood on the front. The rest is made out of same laminated material as the inside cabinets.
Maybe you could lock it with some kind of bar that slides down in front of all the drawers type idea.
Glenn (Wizard)
"The Reel One"
26' Billfisher