RE: The Serenity
The Serenity is indeed 455.5 cm long.
I apologise for providing some bad information (based on some long held "assumptions" I had about the interior length of the 15 foot body on the back of my truck.
I went over to the Windsport Test Site and measured (with an 8 meter tape measure) the length of the Serenity (Wood) I have in the '07 demo fleet.
The board is serial number STSEW06070007.
It meaures 455.5 cm from nose to tail. That translates to 14' 11 3/8".
So, you should have 5/8" clearance inside your 15 foot (diagonal) winter storage locker..
I'd check the diagonal measurement again, to be sure, but the Serenity is very narrow at the bow and stern, so if you indeed have 15 feet, it should fit.
Sorry for any confusion created by the previous double post. I've deleted both of them.
Hope this helps,