where to put it - your antenna that is
We bought a 356 and the dealer mounted the gps antenna on the port side underneath the sternrail seat HULL MOUNTED rather than on a rail. It is out of the way, and there is no degredation of the signal. (On our previous 326 it was mounted on a sternrail seat rail and unwary guests were always using it for a handhold and we constantly lost signal.