Military rank in naval forces
Quarter gunner was a military rank used in naval forces. 
United Kingdom.
In the Royal Navy in the middle of the 18th century, the term "quarter gunner" was used for referring a type of seaman specialized in maintenance of guns. The position was part of the gunner's crew, and one quarter gunner was assigned for every four guns.
United States.
Quarter gunner was a type of petty officer in the ranks of the 19th century United States Navy. Similar to the equivalent rank in Britain, for every four naval guns there would be a quarter gunner. Quarter gunners were under the command of gunner's mates, and were responsible for guns' maintenance and operations.
References.
 ;templatestyles src="Reflist/styles.css" / ;