The black lettering refer to the official naval radio call signs for actual ships. For example, NCOM is the call sign for the USNS Comfort, a hospital ship used as a processing centre of Haitian migrants in 1994. It also served as a floating hospital moored at Pier 92 in Manhattan from the afternoon of the 9/11 Terrorist attack. In 2018 it sailed to offer assistance to countries affected by the Venezuelan refugee crises.

Some of the other call signs included are EBFI for the Spanish rescue ship Audaz, GBSY for HMS Mersey, MGY for The Titanic, MPA for The Carpathia and EADH for SS Navemar. The Navemar is notable for a 1941 voyage in which 1,129 Jewish refugees were taken to the US in overcrowded conditions. Tickets for the few cabins sold at exorbitant prices. The captain charged $2000 to those who could squeeze into his cabin. Bunks were fitted into the filthy coal-holds.