The primary propulsion engine driving the ship's propeller shaft, typically a large slow-speed two-stroke diesel on cargo ships.
Quick facts
Regulation
SOLAS Chapter II
Regulation
MARPOL Annex VI
In practice
The engine's fuel injection, exhaust, and cooling systems are monitored continuously by engine-room watchkeepers or, on UMS vessels, by automated alarm systems linked to the bridge. Routine duties include taking indicator diagrams, checking exhaust temperatures and turbocharger boost pressure, and monitoring crankcase oil mist detectors as required by SOLAS II-1/40. Engineers adjust fuel timing and valve clearances during planned maintenance periods in port or at sea to maintain thermal efficiency and keep exhaust emissions within the limits set by MARPOL Annex VI.
Regulatory detail & full definition
The main engine is the heart of a ship's propulsion system, typically a large slow-speed two-stroke diesel engine directly coupled to the propeller shaft via a thrust block. On most ocean-going cargo vessels these engines turn at between 80 and 120 rpm and develop thousands of kilowatts of shaft power, with some of the largest units exceeding 80,000 kW. SOLAS Chapter II-1 prescribes the structural and machinery requirements for propulsion systems, including redundancy arrangements and shaft alignment standards.
The engine's fuel injection, exhaust, and cooling systems are monitored continuously by engine-room watchkeepers or, on UMS vessels, by automated alarm systems linked to the bridge. Routine duties include taking indicator diagrams, checking exhaust temperatures and turbocharger boost pressure, and monitoring crankcase oil mist detectors as required by SOLAS II-1/40. Engineers adjust fuel timing and valve clearances during planned maintenance periods in port or at sea to maintain thermal efficiency and keep exhaust emissions within the limits set by MARPOL Annex VI.