Well, there is also another berth, 25 Berth Gate 4 in Southampton, which is used when the main berth is out of action, I did create a mission where you berth there instead, but I don't no what happened to it.
Talking of dropping of passengers at Ryde Pier, Wightlink, some MANY years in the past, used to pick up/drop of passengers on their Portsmouth-Fishbourne route at Clarence Pier and Ryde Pier, but this was eventually dropped, and the route just went straight from Portsmouth to Fishbourne