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Certificate of Fitness & LNG Loading Sequence

Chief Mate

times asked: 6; times asked
questions: 2; questions
last asked: 2026; last asked

The slides, written out

AI-drawn illustration. Simplified to explain the idea, not to scale.

Slide 1 · 1/4

CERTIFICATE OF FITNESS & P&A MANUAL Key statutory documents governing LNG and NLS operations CERTIFICATE OF FITNESS (CoF) CoF LNG The ship's licence to carry specific liquefied gas and NLS cargoes in bulk. Lists all approved cargoes by technical name. Never load a cargo not on that list. Specifies design parameters for each tank: Tank type, MAWP, minimum design temperature, relief valve set pressure & relieving capacity. States filling limits based on DSG. MAX FILLING RATIO = DSG / SG × 100 Typical LNG limit: 98% at reference temperature Documents secondary barrier requirements (Type B drip-tray / membrane full barrier, hold space inerting / ventilation). Identifies special equipment or operational restrictions (e.g., IG generator, reliquefaction, vapour return compatibility). The CoF is reviewed during each annual and renewal survey. A Tripartite Agreement may be used for a cargo not yet assessed by IMO, involving the flag state, loading port authority & receiving port authority. P&A MANUAL (MARPOL ANNEX II) P&A MANUAL Required when the ship carries noxious liquid substances (NLS) in bulk. Describes operational procedures to comply with MARPOL Annex II. Pre-wash & tank-cleaning procedures Emergency procedures for NLS spills Slops disposal & retention on board Sampling, stripping & ballasting procedures Cargo Record Book – entries & requirements Procedures that prevent pollution IMPORTANT: A gas tanker that carries only non-NLS cargoes (e.g., pure LNG or LPG without the listed NLS) does NOT need a P&A Manual. The same principle applies to the IPPC Certificate and Cargo Record Book under Annex II.

Slide 2 · 2/4

PRE-LOADING PREPARATION FOR LNG Essential checks and preparations before LNG transfer 1 CARGO VERIFICATION • Confirm LNG (methane) is on CoF • Verify cargo composition • Obtain SDS from shipper 2 LOADING PLAN • Calculate filling limit (98% for LNG) • Account for heel and ullage • Determine available capacity 3 STABILITY & DRAFT CHECK • Verify trim (stern trim preferred) • Check under-keel clearance (UKC) • Ensure compliance with load line 4 SHIP/SHORE SAFETY CHECKLIST • Test ESD link and emergency release • Confirm vapour return connection • Access control & communication test 5 INERTING & DRYING • Inert tank/hold spaces • O₂ level below required limit (<5%)* • Dew point below −45°C • Prevent ice formation *Refer to ship's Cargo Manual for exact O₂ operational limit. CRITICAL LNG PRINCIPLE RAPID COOLING CAUSES THERMAL SHOCK Controlled cooldown is mandatory to protect tank structure. KEY OBJECTIVES Ensure safe operations Prevent icing & thermal shock Protect tank integrity Prevent pollution & emissions IMPORTANT Do not proceed to cooldown or loading until all preparations are completed and verified.

Slide 3 · 3/4

LNG COOLDOWN & CARGO TRANSFER Controlled operations for safe and efficient LNG loading BOG MANAGEMENT To Engine for Fuel To Reliquefaction Plant (if fitted) To Mast Riser (If permitted) VAPOUR (BOG) TEMP. SENSORS LEVEL GAUGE LNG SPRAY (COOLDOWN) PRESSURE MONITOR LNG KEY MONITORING DURING LOADING PRESSURE Keep below relief valve set pressure (typ. 0.25–0.7 bar for LNG) LEVEL Use radar/ultrasonic gauges Avoid stratification TEMPERATURE Ensure uniform cooldown within design limits TRIM & STRESS Adjust ballast to maintain hull girder stresses within permissible limits 1 COOLDOWN Introduce LNG spray into tank Max temperature drop rate ≤ 10°C per hour Target tank temperature: −130°C to −140°C (uniform cooling) 2 LOW-RATE LOADING Start loading at 10–20% of maximum rate Confirm stable cooldown profile Monitor BOG pressure & tank conditions 3 FULL-RATE TRANSFER Increase to full loading rate Monitor and manage tank pressure Manage BOG: engine fuel / reliquefaction / vent Maintain trim and hull stress within limits 4 TOP-OFF PHASE Approaching 98% filling limit Reduce loading rate High level alarm & ESD protection active Prevent overfill at all times 5 VAPOUR RETURN Displaced vapour returned ashore or burned Maintain slight positive pressure to prevent air ingress OPERATION GOLDEN RULE CONTROLLED COOLDOWN + MONITORING = SAFE LOADING Follow Cargo Manual, IGC Code & SIGTTO Best Practices at all times.

Slide 4 · COMPLETION &

COMPLETION & POST-LOADING SAFETY Final steps to secure the cargo and prepare for departure 1 STOP TRANSFER & DISCONNECT Shut cargo valves Blow-down loading arms (Nitrogen / Cooldown & Drain) Disconnect Emergency Release Coupler (ERC) Ensure all loading arms are safe and depressurized 2 SECURE CARGO SYSTEM Close and secure manifold valves Isolate vapour return line Verify tank pressure is stable Confirm all cargo vents and systems secured Maintain tank pressure within design limits 3 DOCUMENTATION & RECORDS Complete Bill of Lading Record cargo transfer details Update Cargo Record Book (if NLS) Make entry in Deck Log and C/O report Accurate records ensure compliance with IGC Code & MARPOL Annex II (where applicable) 4 DEPARTURE READINESS Confirm hold space inerting / ventilation normal Ensure cargo system isolated and secure Verify moorings and fenders ready for safe departure Safety first at every step KEY SAFETY REMINDERS Follow Cargo Manual, IGC Code & SIGTTO Best Practices Monitor Tank Temperature, Pressure & Levels Maintain Communication with Terminal at all times Never bypass alarms, interlocks or safety procedures Manage BOG responsibly – engine / reliq. / vent NEVER LOAD A CARGO NOT LISTED ON THE CoF SAFETY • COMPLIANCE • PROTECTION OF LIFE & ENVIRONMENT

In exams

Asked 6 times across 2 different questions, most recently in 2026. Asked most in Chief Mate (6).

Drafted by SailR from our daily lessons. AI-drawn illustration. Simplified to explain the idea, not to scale. Last updated 19 Oct 2026.

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