Is St Petersburg dock near the city centre?

When Royal Caribbean’s Brilliance of the Seas docks in St Petersburg could you tell me how near to the city centre it is? And, do I need a visa to get into the city?

The Royal Caribbean Brilliance of the Seas docks into Saint Petersburg on the seventh and eighth day of the itinerary. The cruise dock is approximately 15-20 minutes away from the city centre depending on traffic. If you have booked on a fully licensed shore excursion through your cruise line, for example, you will not need a Visa. However if you are determined to explore completely on your own, you must have a tourist Visa to enter Russia; this can be booked online and varies in price depending on when you apply. Prices vary between £73.00 to £210.00