103. Which of the following components provides a direct source of sea water for the fire main system?

Sea chest suction is the correct answer; it directly supplies seawater to systems like the fire main. Sea chests are hull fittings designed to draw seawater from outside the vessel. Rose box suction draws from bilge wells, a stuffing box seals a shaft, and a cofferdam sluice valve connects internal spaces, none of which provide a direct seawater source for the fire main.