Get a cheapo WalMart safebox. put some copies of various papers in there an a few bucks. Leave it unlocked, but hidden in the first place they will look.
meanwhile, money rolls up well in a little PVC tube with end caps, can be stashed in a number of places, and will float if need be. Who would cut open a PVC pipe? Or how bout double ziplocked inside a specific life vest pocket? Hidden in plain sight is best. Everybody knows about the fake food cans.
slightly different subject, but I am curious as to whether anyone here has experience with the .38 caliber steel inserts for flare pistols?