The Firth of Clyde estuary would also be a good area to model, in a small area we have great scenery including high mountainous islands, sandy bays, cities and towns.
There are many large and small ports, 12 ferry routes+ a seacat route to Ireland, a container terminal , graving docks, shipyards, victorian style piers, an ore terminal and a large harbour with estuarial and deep sea tugs, marinas and even a nuclear submarine base.
All of these things in a small area definitely make the Clyde a good choice for shipsim.