Don't C-class ships need three pipes?

Class c ships need three pipes. According to relevant public information, C-class ships need three pipes. Class C ships can be divided into Class C I and Class C II, with a gross tonnage of over 3,000 tons and a gross tonnage of 500 to 3,000 tons. Staffing personnel include: captain, first mate, second mate, third mate, boatswain, carpenter, sailor, helmsman, chief engineer, engineer, mechanic, flight attendant (purser), chef, waiter and ship doctor.