A deck boy on a ship on a convoy to Russia What is the Merchant Navy? The merchant navy is a term used to refer to the commercial sector of the maritime industry. The merchant navy has no involvement in military service, but rather the shipping of cargo and people across sea routes aboard cargo ships, tankers, and cruise liners. Merchant seamen crewed the ships of the British Merchant Navy which kept the United Kingdom supplied with raw materials, arms, ammunition, fuel, food and all of the necessities of a nation at war…