| Abbreviation | Definition |
|---|---|
| PCH | Patrol Craft, Hydrofoil |
| PCM | Patrol Craft, Missile |
| PCS | Patrol Craft, anti-Submarine |
| PF | Patrol Frigate |
| PG | Patrol Gunboat |
| PGG | Guided-missile Gunboat (Patrol, Gunboat, Guided-missile) |
| PGH | Patrol Gunboat, Hydrofoil |
| PHM | Patrol Hydrofoil Missile |
| PMB | Pilot Mail Boat |
| PR | River Gunboat (Patrol, River) |
| PSNS | Puget Sound Naval Shipyard |
| PSV | Platform Supply Vessel |
| PT | Torpedo Boat (Patrol, Torpedo) |
| PTF | Fast Torpedo Boat (Patrol, Torpedo, Fast) |
| PTGB | Torpedo GunBoat (Patrol, Torpedo, GunBoat) |
| PTH | Patrol Torpedo, Hydrofoil |
| ptn | pontoon |
| QAWT | Quick Acting Water-Tight |
| R.M.S. | Royal Mail Ship |
| RC | Revenue Cutter |