Harold is a rich young idler who falls in love with Mildred:  "She averages six proposals a day, including Sundays and holidays."  He decides he wants to marry her ("...It's too hot to play croquet; let's get married"), and she directs him to her father, who stipulates that Harold must prove he can do something other than loaf.

Harold "puts his shoulder to the wheel" by enlisting in the Navy.  Mildred and her friends embark on a long trip on her father's yacht.  Harold tries to cancel his enlistment, but to no avail.  On the ship, Harold dreams he is an admiral―in a dual role, he takes orders from himself.

Harold encounters Rough-House, who is impressed when Harold accidentally knocks out the Navy's boxing champion.  The ship sails into port at Khaipura-Bhandanna.  The Maharajah has taken a liking to Mildred, and kidnaps her.  Harold uses comic acrobatics to rescue her from the palace, eventually retrieving the key to the room she is locked in, and escaping from the Black Castle with his betrothed.

What was said about A Sailor-Made Man:

Wid’s Daily (November 27,1921)
"Lloyd again demonstrates in this the possibility of straight clean comedy without resorting to slapstick or smutty effects. His comedy is clean, straight, and decent."

Motion Picture News (December 3, 1921)
"It is a carefully worked-out comedy, there being a stamp of rehearsal over it which indicates that Lloyd never offers anything haphazardly conceived and executed."