Question 1

The bosun requests permission to carry out welding on the forecastle deck to repair a mooring chock. As OOW in port, what are your obligations before authorising any hot work?

Accepted Answer

A hot work permit must be issued before any welding, cutting, or grinding where sparks or heat can ignite surrounding materials. Before issuing: identify fire risks in the area and adjacent spaces (fuel pipes, paint stores, electrical cables, wooden fittings); ensure a fire watch is posted during work and for 30-60 minutes afterwards (smouldering fires take time to develop); ensure fire extinguishers and a charged hose are immediately available; check wind direction — sparks travel downwind; identify nearest fire detection coverage for the area. The permit specifies: location, nature of work, time period, fire precautions, who is responsible. In port, inform port authority if their hot work permit procedures apply. The OOW does not sign the permit — in most SMS systems, the master or chief officer signs. The OOW must verify precautions are in place. The hot work permit system is a fundamental element of the ISM Code SMS and is specifically required under COSWP Chapter 16. Fires started by hot work are among the most preventable causes of shipboard fire — and among the most common. Key points: (a) the fire watch must continue after work ends — smouldering fires in insulation, paint coatings, or dry timber can take 30-60 minutes to develop into open flame; (b) adjacent spaces must be checked — sparks travel through gaps, voids, and deck penetrations; (c) in port, many terminals require prior notification to their fire team and may have their own hot work permit system that must be complied with in addition to the ship's system; (d) the OOW's role in most SMS systems is to check that precautions are in place, not to sign the permit — but they have authority to stop work if precautions are inadequate. Multiple MAIB investigations have found hot work permits issued without adequate fire watch arrangements as a contributory factor.

Question 2

Your examiner asks: "Describe the fire triangle and the four internationally recognised classes of fire relevant to shipboard operations. Which extinguishing media are correct for each?"

Accepted Answer

The fire triangle requires three elements simultaneously: heat (ignition source), fuel (combustible material), and oxygen. Remove any one element and the fire goes out. Classes: Class A — solids (wood, rope, bedding) — water, foam, dry powder; Class B — flammable liquids (fuel oil, paint, solvents) — foam, CO2, dry powder; Class C — flammable gases (LPG, acetylene) — dry powder, shut off supply first; Class D — combustible metals (magnesium, titanium, sodium) — specialist dry powder only; Class F (electrical equipment) — CO2, dry powder — NEVER water. Note: electrical fires are sometimes classed separately rather than as a fire class. The fire triangle (heat, fuel, oxygen) underpins all firefighting strategy: cooling removes heat (water); smothering removes oxygen (CO2, foam blanket); starvation removes fuel (shut off supply, remove combustible material). Note the tetrahedron model adds a fourth element — the chain reaction — which halite extinguishing agents (Halon, now banned under MARPOL Annex VI except for existing systems) interrupt. Electrical fires (Class F in some classifications) must never be fought with water or foam — both conduct electricity. CO2 is the correct agent for switchboard and electrical equipment fires. Class D fires (metals) react violently with water — specialist dry powder (not standard ABC powder) is the only safe option. At OOW level, the examiner expects correct extinguishing media for each class and awareness that using the wrong agent can be dangerous.

Question 3

Your examiner asks: "What types of fire detectors are fitted on cargo ships under SOLAS Chapter II-2, and what are the conditions under which each type is most effective?"

Accepted Answer

Smoke detectors (ionisation or photoelectric): detect combustion particles — most effective for smouldering fires producing visible or invisible smoke before open flame. Heat detectors: either fixed-temperature (alarm at a set temperature, e.g. 57-96 degrees) or rate-of-rise (alarm when temperature rises faster than normal, e.g. 5 degrees per minute) — effective for fast-burning fires. Flame detectors: detect infrared or ultraviolet radiation from open flames — effective in machinery spaces with high background heat. Gas/carbon monoxide detectors: detect CO as an early indicator of smouldering fires. SOLAS II-2/7 requires automatic fire detection and alarm systems in crew accommodation, service spaces, control stations, and cargo spaces as appropriate. SOLAS II-2 Chapter 7 and the FSS Code Chapter 9 govern fire detection requirements. Key point for OOW orals: smoke detectors are the most sensitive for early detection of smouldering fires (which produce CO and aerosols before visible flames) — they are required in accommodation spaces. Heat detectors are more appropriate in galleys and machinery spaces where ambient temperatures and aerosols (cooking fumes, diesel exhaust) would cause false alarms from smoke detectors. Rate-of-rise detectors are faster-responding than fixed-temperature but can false-alarm in areas with rapid legitimate temperature changes (boiler rooms, hot work areas). Flame detectors are specifically required in unmanned machinery spaces. CO detectors as an early warning layer are increasingly specified in cargo hold monitoring systems. The FSS Code divides spaces into three categories: A (accommodation), B (service/machinery), and C (cargo) — each has specific detection requirements.