First appearance of Popeye in white U.S. Navy uniform.
The short was released less than a month before the attack on Pearl Harbor, which sent both regular folks as well as cartoon characters off to enlist.
The flag sight gag "Enemy (Name Your Own)" was a broad wink to the war in Europe and the far East already happening. Had this short been created after 1941, the flag would have undoubtedly been Japanese.
The officer wears three stripes on his uniform sleeve, indicating the rank of Commander. A Captain wears four stripes.
Although the short was released just before the US entered WW2, the title has a prominent capital V in the word Navy. V for victory was a wartime slogan popularized by Winston Churchill in the spring of 1941.