Final answer:
The statement is false as it contradicts standard maritime 'port-to-port' passing rules where both vessels would pass with their port sides facing each other, but context is needed to determine the correct maneuver.
Step-by-step explanation:
The statement "Both vessels shall alter their course to starboard and shall pass on the port side of the other" is False. In standard maritime navigation rules, vessels would alter their courses to starboard only if they are following the 'port-to-port' passing rule, which means both vessels would pass with their port (left) sides facing each other. However, without specific context or additional rules like the International Regulations for Preventing Collisions at Sea (COLREGs), we cannot definitively determine the correct maneuver.