A tanker is a ship built to carry liquid cargo in bulk, using internal cargo tanks rather than containers or open holds. Tankers form one of the highest-value and most heavily regulated segments of the merchant fleet.
Main Tanker Types
- Crude oil tankers — carry unrefined crude oil, ranging up to VLCC (Very Large Crude Carrier) and ULCC (Ultra Large Crude Carrier) sizes
- Product tankers — carry refined petroleum products (diesel, gasoline, jet fuel)
- Chemical tankers — carry a wide range of liquid chemicals, requiring specialized tank coatings and strict cargo segregation
- LNG/LPG carriers — carry liquefied natural or petroleum gas at very low temperatures, requiring specialized containment systems
Key Safety Features
- Inert gas systems — filling cargo tank space with inert gas to prevent explosive atmospheres
- Double hull construction — mandatory under MARPOL for oil tankers, reducing spill risk from side collisions or groundings
- Crude oil washing (COW) — cleaning tanks using the cargo itself during discharge, reducing residue and pollution risk
Additional Certification
Joining a tanker requires Tanker Familiarization training beyond standard STCW Basic Safety Training, given the specific hazards of flammable and hazardous liquid cargo.
Exam Relevance
Tanker cargo operations, inert gas systems, and MARPOL Annex I compliance are core Cargo Work topics for deck officers, with additional depth required for tanker-specific endorsements.