Tickets for the Maritime Museum Ferry (which runs subject to weather conditions in the off season) cost 1.50zł each way, and can be ridden by anyone, regardless of whether you're visiting the museum. As such, it offers a very handy shortcut for those simply looking to get to the other side of the river. However, there is now a bridge from the Crane to the Granaries' side.
NOTE on Ticket Prices:
There is a combined ticket option for Granaries, "Sołdek" ship museum and the Crane that costs 25/16zł.
The National Maritime Museum's interactive exhibition Ludzie-Statki-Porty (ENG: People-Ships-Ports) is available 12 zł / 8 zł.
A regular ticket for the Granaries costs 12/8zł and is free on Wednesdays.
Keep in mind that combined tickets are available for the museum-owned granaries, Sołdek ship museum, the Crane and the Maritime Cultural Centre including the interactive exhibition for 30 zł / 20 zł. However, if you do not want to include the interactive exhibition in your ticket, it will be 25 zł / 16 zł.