| COMMISSIONED OFFICERS | ||
| ABBREVIATION | RANK/RATE | DUTIES |
| MIDN | Midshipman | Cadet at U.S. Naval Academy |
| WO | Warrant Officer | An officer with prior enlisted experience |
| CWO | Chief Warrant Officer | An officer with prior enlisted experience |
| ENS | Ensign | Division Officer |
| LTJG | Lieutenant (junior grade) | Division Officer |
| LT | Lieutenant | Department Head (Engineer, Navigator, etc.) |
| LCDR | Lieutenant Commander | Commanding Officer of Destroyer Escort |
| CDR | Commander | Commanding Officer of Destroyer |
| CAPT | Captain | Commanding Officer of Escort Carrier |
| COMO | Commodore | Screen Commander |
| RADM | Rear Admiral | Commander of Task Unit or Task Group |
| VADM | Vice Admiral | Commander of Task Group or Task Force |
| FADM | Fleet Admiral | Commander-in-Chief of Fleet |
| NON-COMMISSIONED ENLISTED | ||
| ABBREVIATION | RANK/RATE | DUTIES |
| ACRM | Aviation Chief Radioman | Transmit and receive radio messages. Encipher and decipher messages. |
| AEM | Aviation Electrician's Mate | Inspect, maintain, repair and install all electrical equipment in aircraft. |
| AerM | Aerographer's Mate | Make weather observations. Read weather codes and signals. |
| AM | Aviation Metalsmith | Repair airplane metal parts. Know principles and theory of flying. |
| AMM | Aviation Machinist's Mate | Assemble, service and repair airplanes and airplane engines. Splice aircraft wiring. Know principles and theory of flying. |
| AMMC | Aviation Machinist's Mate C | Aviation carburetor mechanic. |
| AOM | Aviation Ordnanceman | Handle and take care of all aviation weapons. |
| ARM | Aviation Radioman | Operate radio transmitting and receiving equipment of naval aircraft. |
| ART | Aviation Radio Technician | Maintain all aviation radio equipment. |
| B | Boilermaker | Fit pipes, make repairs in boilers. Know construction of marine boilers and fireroom safety precautions. |
| Bgmstr | Buglemaster | Know all bugle and drum calls and honors rendered. Lead and instruct a corps. |
| BkR | Baker | Operate ovens. Do any kind of baking. |
| BM | Boatswain's Mate | Work with canvas and hoisting with block and tackle. Handle rope, wire, and anchor chain. Handle power and sail boats. Steer ship and chart courses. Direct salvage. |
| Bug | Bugler | Play in a bugle and drum corps. Know bugle calls and honors. |
| CK | Cook | Take charge of galley. |
| CM | Carpenter's Mate | Use hand and power tools. Take charge of ship ventilation, painting, watertight control, drainage. Understand shoring and drydocking. |
| COX | Coxswain | Work with canvas and handle boats. Know signaling. |
| EM | Electrician's Mate | Use electrical tools and repair electrical equipment. Charge storage batteries. Wind armatures. Stand watch on main gyrocompass and in main control room of electrically driven ships. Repair telephone circuits. Apply first aid in case of electrical shock. |
| F | Fireman | Fire and tend boilers. Operate, adjust and repair pumps. |
| FC | Fire Controlman | Stow, inspect and repair fire control instruments. Take charge of fire control equipment. Know electricity - A.C. and D.C. Man fire control stations. |
| GM | Gunner's Mate | Take charge of gun and crew. Assemble and fire all types of guns. Handle ammunition. Handle mines and depth charges. |
| HA | Hospital Apprentice | Know minor surgery, first aid and nursing. Maintain sanitary conditions. |
| M | Metalsmith | Make plans, time and cost estimates. Work in copper and brass. Temper metals, repair damage. Test for watertightness. |
| ML | Molder | Equip and work in foundry. Make castings. Use molding tools. Operate oil furnaces. |
| MM | Machinist's Mate | Operate main and auxiliary engines. Adjust, repair, and overhaul engines. Be familiar with ship's drainage systems, distilling plants, evaporators and pumps. |
| MMS | Machinist's Mate S | Shop machinist. |
| MoMM | Motor Machinist's Mate | Operate machine tools. Operate and maintain internal combustion engines and engine auxiliaries. Knowledge of pressure and air systems. Be familiar with electrical apparatus. |
| PhM | Pharmacist's Mate | Take charge of sick bay. Do minor surgery and administer simple medicines. |
| PhoM | Photographer's Mate | Organize and direct operations of Naval photographic units. Operate motion picture machines. Develop negatives and make prints. |
| PR | Parachute Rigger | Pack and repair parachutes. Parachute jumping experience. |
| Prtr | Printer | Take charge of ship's printshop, set type. Read proof. |
| QM | Quartermaster | Steer ship and take soundings. Use range finder. Plot bearings. Know signal control and navigation. Send and receive International Code by blinker, searchlight and semaphore. |
| RdM | Radarman | Stand radar watch and operate radar equipment. |
| RE | Radio Electrician | Maintain radio equipment. |
| RM | Radioman | Transmit and receive radio messages. Encipher and decipher messages. |
| RT | Radio Technician | Maintain radio equipment. |
| S | Seaman | Know naval drill duties, knots, steering and signaling. Stand watch and gunnery duties. |
| SC | Ship's Cook | Supervise and prepare cooking. |
| SF | Shipfitter | Use hand and machine tools for steel metal work. Bend, repair and fit pipes. Operate fire extinguishers and rescue breathing apparatus. |
| SK | Storekeeper | Take charge of ship's storeroom. Issue and account for stock and clothing. |
| SKV | Storekeeper V | Aviation Storekeeper. |
| SM | Signalman | Stand signal watch on bridge. Identify flags. Use blinker, searchlight and semaphore. Use range finder, searchlights, signal apparatus. |
| SoM | Soundman | Operate special sound equipment. |
| StM | Steward's Mate | Serve at table in officers' mess. |
| TM | Torpedoman's Mate | Lubricate, assemble, charge and fire torpedoes. Lay mines and drop depth charges. |
| WT | Water Tender | Take charge of fireroom when under way. Maintain, repair, and overhaul boiler system. |
| Y | Yeoman | Take charge of ship's office. Take dictation, write Navy letters. Prepare reports and keep personnel records. |
|
ENLISTED RANK STRUCTURE |
|
| C | Chief Petty Officer |
| 1c | Petty Officer First Class |
| 2c | Petty Officer Second Class |
| 3c | Petty Officer Third Class |
| S1c | Seaman First Class |
| S2c | Seaman Second Class |
| EXAMPLES | |
| CEM | Chief Electrician's Mate |
| GM1c | Gunner's Mate First Class |
| AM2c | Aviation Metalsmith Second Class |
| SM3c | Signalman Third Class |
Source: The Bluejacket's Manual 12th edition. (Annapolis, MD.: U.S. Naval Institute, 1944).