Perfect irony that you should mention 'Gilligan's Island'. My Bainbridge Island pal was at his Mailbox one day. The Lots across the Lane are the usual long & narrow config so that more folks can have a Dock w/water access via skinny Lots. Who does he meet at the communal Mailboxes? The 'Professor' from Gilligan's Island; his Neighbor who's into Sailing. The beginning of that Show was filmed at the Breakwater Jetty at Balboa Beach CA. Sailed it many times...
From all I've seen to date, the true RV Brownout protectors are kinda pricy. But, they're justified, perhaps, in that they protect high value items when the Blenders kick on.