If you ae lucky to stay at the Rock Hotel a number of the rooms have balconies facing the Bay. The panoramic vista that opens out before you is staggering. They have a a couple of PCs in a computer room to go onto whatever AIS based internet program you use. Marinetraffic, fleetmon, vesselfinder, shiptracking etc...
A good position to go to is the Cable Car to the top of the Rock. There is a cafe there and the apes get fed up there IIRC. This position there are excellent views over the eastern anchorage. Be aware of the ape poo!!
You can get out onto the bay by getting a ticket to board one of the dolphin boats [dolphin adventure dolphin safari] both have internet web sites and you can purchase tickets on it. So you can not only look at the marine life ... when it pops up, but also get some excellent photograpphs of the varoious ships moored in the bay.
I use a Canon EOS 700D with a 100-400mm lens