Outline: A fun blowout day activity.

Divide your group into two or more teams and send on a scavenger hunt. The
kids race to gather as much material as possible from surrounding environs:
lifejackets, wetsuits, old sails, paddles, tyres, etc.

The teams then assemble the material into a giant collage on the ground
(best done somewhere it's possible to get an ariel view). Bonus marks for
sailing-related creativity.