Berlin: an empty oil tanker doing a test run to see if it can actually navigate the passage. It is something like this: http://dolfijn1962.deviantart.com/art/German-oil-chemical-tanker-Ellen-Essberger-2004-370752325
The Canadian Arctic is divided into zones based on when the sea ice appears in the fall and disappears in the spring. If a vessel wants to enter a zone before or after what is determined to be the ice-free date, they have to have an ice pilot on board (meaning a pilot who is trained and has a certain number of hours of experience navigating through ice) or they have to be escorted by a Coast Guard icebreaker. In the play, the Berlin completely by-passes that rule. So when Thomas asks if they have an ice pilot on board, he is trying to find out if there’s anyone on board who knows how to handle the Arctic environment.