The examiner asks the master to explain the SOLAS requirements for immersion suits on a cargo vessel, including who must have one, the size requirements, and the maintenance obligations.

A. IMMERSION SUITS — SOLAS REQUIREMENTS AND MASTER's OBLIGATIONS: WHO MUST HAVE AN IMMERSION SUIT (SOLAS III/7): (1) Every person on board a cargo ship must have an immersion suit of the appropriate size; (2) In addition, sufficient insulated immersion suits for persons on watch duty who are not assigned to lifeboats must be available at the navigation bridge and engine room; (3) For cargo ships on voyages in warm climates (above a defined latitude where immersion suits are not required for thermal protection), the flag state may exempt — but lifejackets with lights and reflectors are still required. SIZE REQUIREMENTS — LSA CODE AND MLC 2006 AMENDMENT 2014: the immersion suit must fit the individual who will wear it. Sizes must cover the range of crew present on board — not just a standard size. If a crew member falls outside standard sizes, a custom-fit suit must be provided. This is a MLC 2006 amendment requirement that specifically addresses sizing inclusivity (related to MLC A4.3 on PPE). MAINTENANCE: (1) Annual inspection of suits, including testing of zip, seals, inflation device (if fitted), and reflective tape condition; (2) Record all inspections in the ship's safety record; (3) Replace expired suits or suits with defects; (4) Monthly visual check as part of LSA inspection log; (5) DONNING DRILL: crew must be able to don their immersion suit in 2 minutes including lifejacket (SOLAS — timed drill requirement). STORAGE: immersion suits stored in crew cabins or at muster station — must be accessible in the dark.

B. Immersion suits are only required for cold water routes. A vessel trading in the tropics does not need to carry immersion suits for all crew — lifejackets are sufficient.

C. One immersion suit per lifeboat station is sufficient. Individual assignment is not required — suits are shared and used by whoever reaches the muster station first.

D. Immersion suits only need to be inspected at annual dry dock by the classification society. Between dry docks, monthly checks are the crew's personal responsibility and not recorded in the ship's log.

A. ABANDON SHIP DECISION — COMMAND AUTHORITY AND FRAMEWORK: THE MASTER'S AUTHORITY: SOLAS Chapter III and the ISM Code place the abandon ship decision exclusively with the master. The company can advise but cannot override the master's decision on abandonment — SOLAS V/34.1 confirms the master's ultimate authority for safety. TIMING CONSIDERATIONS: abandon ship is a last resort — the following criteria support the decision: (1) Fire cannot be controlled or contained and is spreading; (2) The vessel's structural integrity is threatened (fire in hold = risk of structural steel softening); (3) The fire is approaching fuel tanks, cargo spaces or gas lines; (4) Crew casualties are occurring or the crew cannot fight the fire safely; (5) The vessel is listing or there are signs of progressive flooding; (6) MRCC has been informed and rescue assets are en route. DECISION PROCESS: (1) Assess the fire situation honestly — is containment possible? (2) Contact MRCC: transmit Mayday if not already done, give position, vessel size, crew number, nature of emergency; (3) Prepare lifeboats and liferafts — muster crew at stations (this is preparation, not abandonment); (4) Give the order only when the vessel is no longer safe to remain on board; (5) THE SIGNAL: 7 short blasts + 1 long blast on the ship's whistle and alarm system; (6) Confirm crew muster complete before ordering "abandon ship." The sequence: Mayday → muster → prepare boats → last-resort order.

B. Abandon ship as soon as the fire cannot be controlled in the first 10 minutes. Early evacuation is always safer than remaining on a burning vessel.

C. Contact the company DPA and wait for authorisation before ordering abandon ship. The master cannot make the abandon ship decision independently without company approval.

D. Order all crew to liferafts immediately and do not attempt to lower the lifeboats in a fire situation — lifeboat fuel tanks may ignite.

A. CO₂ TOTAL FLOODING — COMMAND DECISION PROCESS: WHY CARE IS REQUIRED: CO₂ at fire-extinguishing concentrations (34%+ in air) is instantly fatal to any person in the space. Premature or incorrect CO₂ release has killed crew members. The decision must be deliberate and methodical. DECISION PROCESS: (1) CONFIRM FIRE: (a) Is this a genuine fire or a detector fault/false alarm? Visual confirmation via CCTV or access port; (b) Smoke odour in adjoining spaces; (c) Temperature alarms; (2) CONFIRM SPACE IS EVACUATED: (a) Account for ALL persons who may be in the engine room — use the muster list; (b) Any engineer on watch must be accounted for; (c) Check all access points and adjoining spaces; (3) CLOSE AIR SUPPLY: shut all ventilation fans, air intakes, and dampers to the engine room — CO₂ is only effective in a sealed space; (4) STOP FUEL OIL SUPPLY to reduce fire fuel load; (5) SOUND CO₂ ALARM (typically a horn or klaxon in the space) for a mandatory warning period before release (SOLAS requirement); (6) CONFIRM RELEASE WITH CHIEF ENGINEER: the decision to release should be a coordinated command decision; (7) RELEASE CO₂: activate from the CO₂ release station; (8) DO NOT ENTER for minimum 30 minutes after release — CO₂ dissipates but atmosphere must be tested before re-entry.

B. Activate the CO₂ system immediately when the detector alarms — speed is critical and any delay risks fire spread. Pre-release checks slow down the response.

C. CO₂ systems activate automatically when the smoke detector reaches a threshold — manual activation by the master is not required and the master should monitor rather than intervene.

D. Use the portable CO₂ extinguishers first. The fixed CO₂ total flooding system should only be used as an absolute last resort when all other methods have failed.