This was the beginning of his painting career at sea.
He would then make a series of paintings in various ports: Le Havre, Antwerp, and Rotterdam.
He sailed for the first time in 1929 to explore new horizons, and he boarded sailing boats to paint the fishermen on the banks of Newfoundland and Greenland.
In the 1930s, he became the painter of the main French naval armaments, and in 1936, he was named Peintre de la Marine and became a member of the Naval Academy.
During World War II, Chapelet served on the transatlantic convoys between 1939 and 1940.
From 1942 to 1945, he served as commissioner of the navy in the Mediterranean, and in 1946, in Indochina.
Meanwhile, he continued to paint different military operations and naval battles.