Marine Engineering - Propulsion Matching, Fire Safety and Emissions
Marine Engineering
This domain tests propulsion plant selection, auxiliary systems, and the environmental and fire-safety rules that govern machinery. For PRC-flagged ships the applicable texts are SOLAS II-1 and II-2, MARPOL Annex VI and the MSA statutory technical rules, with CCS class rules covering the machinery installation itself.
Core rules
- Engine–propeller matching: the propeller curve (P ∝ n³) and the engine layout diagram; sea margin and light-running margin are added to the trial-condition power.
- Fire safety: machinery space of category A, fixed firefighting for large engine rooms, quick-closing valves, and an emergency source of power outside the space.
- MARPOL Annex VI: global sulphur 0.50% since 1 January 2020; 0.10% in ECAs. China's domestic emission control areas (DECA) require 0.10% sulphur in core ports and 0.50% in the wider coastal ECA.
- EEDI applies to new ships above the size thresholds; EEXI (2023) to existing ships; CII rating A–E annually.
- Ballast water: BWM Convention D-2 standard, approved BWMS and a Ballast Water Record Book.
Worked example
A 50,000 DWT bulk carrier, V_ref 14 kn, main engine 8,000 kW at 75% MCR, SFOC 170 g/kWh, HFO with C_F = 3.114. CO₂ per hour = 8,000 × 170 × 3.114 = 4,235,040 g = 4.235 t/h. Per day = 101.6 t. Distance per day = 14 × 24 = 336 nm. CO₂ per nm = 0.3025 t. EEDI = 0.3025 × 10⁶ / 50,000 = 6.05 g CO₂/(t·nm). This figure only means something against the required value for that ship type and size on the reference line.
Traps
Using MCR instead of 75% MCR in EEDI; mixing SFOC units (g/kWh vs kg/kWh); applying EEDI to existing ships rather than EEXI; assuming DECA limits equal the global cap.