Marlin is 131 feet in length with a beam of 13.5 feet and is equipped for surface, submerged, and snorkel operations. Accommodations are provided for a crew of two officers and 16 enlisted men. The torpedo room is the forward compartment containing the solitary tube, the torpedoes ready for firing, the forward escape trunk, and berths and lockers for the crew.
The forward quarters contains the crew's mess facilities. In this area the food stowage, galley and scullery, a head and washroom (with shower), and additional lockers are arranged. Below decks is the forward main battery.
The control room is the center for steering and diving control, fire control, and submerged conning. Included herein are the periscope, radar and sonar equipment, trimming and stability controls, and hull opening indicators.
The after quarters housed the radio room, office supplies, and berths and lockers for the subs two officers. Below this compartment is the after battery.
Last is the machinery spaces. This area is the maneuvering control station for the main propulsion equipment. Here are the twin diesel engines, main generators, main motors, distilling plant, main hydraulic system, and air compressors.
The Marlin's size is a remarkable contrast to the larger Gato and Balao class fleet subs of World War II, and even more so to the colossal modern missile submarines of today. But her diminutive size actually enhanced her function as a target submarine; if our ASW forces developed the skills to detect the elusive Marlin during fleet training exercises, what chance would a Russian Akula or Typhoon stand? And if the Cuban missile crisis had chain-reacted into a shooting war, only Marlin could have penetrated the bays and harbors the enemy ships would have used as refuge from our nuclear attack subs. We can be thankful she was never needed in this capacity, and reassured that if she was needed, Marlin would have pulled her weight, and more.