I bet you will find an enormous amount of ideas here
" Sail Away from the Safe Harbor". . .Dream. Mark Twain
"Set Your Sails on an Adventure of Your Life . . .Read'
I particularly like. . ." Treasure is not just Silver and Gold." . . captain Jack Sparrow ( you can add to that quote. " Open a Book and Discover it"s Treasure
If you do a newsletter, information board, or calendar you could title it "Scuttlebut Sailing News"
for math " Point Your Compass Towards___" Draw a large Compass
"Shiver Me Timbers" it's Halloween ( Acknowledge any holiday or special event)
I def. would include a treasure chest ( map), perhaps a crow"s nest, and a ship with you students on board. Have Fun