| S&P | - | Sale & Purchase |
| SAFCON | - | Cargo Ship Safety Construction Certificate |
| SANR | - | Subject to Approval, No Risk |
| SAR | - | Search And Rescue |
| SARSAT | - | Search And Rescue Satellite System |
| SART | - | Search And Rescue Radar Transponder |
| SATCOM | - | Satellite Communications |
| SB | - | Safe Berth |
| SBM | - | Single Buoy Mooring |
| SBS | - | Surveyed Before Shipment |
| SBT | - | Segregated Ballast Tank |
| SC | - | Salvage Charges |
| | - | Short Circuit |
| SCNT | - | Suez Canal Nett Tonnage |
| SD | - | Sailing Date |
| | - | Short Delivery |
| | - | Standard Design |
| | - | Single Decker |
| SDR | - | Special Drawing Rights |
| SF | - | Safety Factor |
| | - | Stowage Factor |
| | - | Shear Force |
| SG | - | Specific Gravity |
| SHEX | - | Sundays, Holidays Excluded |
| SHINC | - | Sundays, Holidays Included |
| SHP | - | Shaft Horse Power |
| SIGTTO | - | Society of International Gas Tanker and Terminal Operators |
| SLA | - | Single Line Approach |
| SMC | - | Safety Management Certificate |
| SMS | - | Safety Management System |
| S/N | - | Shipping Note |
| SNST | - | Soonest |
| S/O | - | Shipping Order |
| SOC | - | Shipper Owned Carrier |
| SOF | - | Statement Of Facts |
| SOFAR | - | Sound Fixing And Ranging |
| SOL | - | Shipowner's Liability |
| SOLAS | - | The International Convention for the Safety Of Life At Sea |
| SONAR | - | Sound Operation Navigation And Range |
| SOPEP | - | Ship and Shore Oil Pollution Emergency Plan |
| SP | - | Safe Port |
| SPC | - | Self-Polishing Copolymers |
| SPD | - | Steamer Pays Dues |
| SPM | - | Single Point Mooring |
| SRL | - | Ship Repairer's Liability |
| SS | - | Special Survey |
| | - | Steam Ship |
| SSB | - | Single Side Band |
| SSHEX | - | Saturdays, Sundays, Holidays Excluded |
| SSHINC | - | Saturdays, Sundays, Holidays Included |
| SSN | - | Standard Shipping Note |
| SSO | - | Ship Security Officer |
| SSW | - | Summer Salt Water |
| ST | - | Short Ton |
| | - | Standard Time |
| STBY | - | Standby |
| STC | - | Said To Contain |
| STCW | - | Standards of Training, Certification and Watchkeeping (convention) |
| STD | - | Standard |
| STEL | - | Short Term Exposure Limit |
| STL | - | Submerged Turret Loading |
| SWAD | - | Salt Water Arrival Draught |
| SWASH | - | Small Waterplane Area Single Hull |
| SWATH | - | Small Waterplane Area Twin Hull |
| SWBM | - | Still Water Bending Moment |
| SWDD | - | Salt Water Departure Draught |
| SWL | - | Safe Working Load |
