So I wanted music for surfing but not tower speakers.  The ski pylon seemed like a good mounting point so I came up with a removable setup that sets on the pylon and plugs into a Neutrik jack in the rear locker.  Just a couple Krypt cans, Polk MM651-UM speakers, and a bunch of PVC.  The cans can rotate about 30 degrees and stay level so when the bow goes up they'll keep pointing straight back.  The unit can be turned so it can be pointed into the cockpit or in any direction for floating/swimming