I am intrigued that you are describing what is essentially a beach environment. My experience patrolling the beaches of Channel Islands national Park suggests that the beach is a very good place to be if you are trying to corral goodies in a survival situation.

I have found working flashlights (more than once), in additional to various other items related to scuba diving, literally miles of rope (usually the yellow polyester stuff), nautical charts, consumable food, a usable walking staff, clothing items (some of which were usable). All this was in addition to the ostensible objects of my search, - archeology, historic shipwrecks, and pygmy mammoth fossils. Moving water transports objects a long way...Oh, yes, there were also two messages in a bottle, but, alas, no magic lamp complete with genie. It got to the point where I made regular use of the yellow rope to fabricate fossil casts, never bothering to carry any until we could scoop up some along the shore.

Not only all these found objects, but in a lot of environments, you are going to have food readily at hand - mostly mussels and other crustaceans. The beach is where it's at!