Seven crew members have fallen ill with fever, vomiting, and diarrhoea 48 hours into a trans-Atlantic crossing. As master, what public health obligations and practical response do you invoke?

A. OUTBREAK OF ILLNESS — Master's public health response: (1) ISOLATE: immediately isolate affected crew from food preparation and contact with healthy crew; if gastrointestinal illness — potential norovirus, salmonella, or similar; source may be contaminated water or food; (2) RADIO MEDICAL ADVICE: contact TMAS (radio medical service) immediately — describe symptoms, onset, number affected, severity; follow medical guidance on treatment and isolation; (3) IHR (International Health Regulations 2005 — WHO): ships are required under IHR to notify the next port's designated point of entry (Public Health authority) before arrival if there is a suspected outbreak of a disease of international public health concern. Complete the Maritime Declaration of Health (MDH) accurately; (4) FOOD AND WATER INVESTIGATION: preserve all food samples from the last 48 hours in the fridge — do not discard anything; check the water tanks for contamination (test if chlorination levels are correct — minimum 0.2 ppm residual chlorine); (5) HYGIENE MEASURES: increase handwashing requirements for all crew; close the galley if the cook is affected — switch to pre-packaged food; disinfect all common surfaces; (6) LOG: document all ill crew names, onset times, symptoms, treatment; (7) MAYDAY: if illness is life-threatening (dehydration, high fever, deterioration) — consider medical diversion or helicopter casevac for the most severely ill.

B. Keep the illness confidential until reaching port to avoid quarantine delays. Declaring an outbreak will result in the vessel being held at anchor for weeks.

C. Treat all ill crew with antibiotics from the ship's medical stores immediately. Antibiotics are effective against all gastrointestinal illness.

D. An outbreak affecting 7 crew is not significant — illness affecting fewer than 25% of crew does not trigger IHR reporting obligations.

A. ABANDON SHIP DECISION — command analysis: (1) FACTORS FOR IMMEDIATE ABANDON: fire has breached CO2 total flooding — the fixed system has failed; structural integrity now at risk; uncontrolled fire progression; water temperature 6°C limits survival time to approximately 30-60 minutes — the sooner into the water, the more daylight/SAR time available; (2) FACTORS AGAINST IMMEDIATE ABANDON: night-time, North Atlantic, Force 7-8 conditions — launching lifeboats in these conditions is extremely hazardous and may itself cause casualties; is there a safe refuge (citadel/fire boundary not yet breached); is a SAR helicopter or vessel ETA within 30-60 minutes (survival time in 6°C water); (3) DECISION FRAMEWORK: the master makes this call balancing the risk of remaining (growing fire) against the risk of abandonment (cold water, sea conditions). International guideline (IAMSAR/IMO Resolution): abandon ship when the vessel can no longer be considered a safe platform. In this scenario — uncontrolled fire with CO2 failure and structural risk = abandon; (4) TIMING: ensure EPIRB is activated, MAYDAY is sent, lifeboat/raft is ready BEFORE giving the order — do not order abandon before the means of abandonment are ready; (5) POSTMASTER'S AUTHORITY: no one else can give the order to abandon ship; the master does not wait for the company's permission — ISM Ch 5.2 expressly states the master's overriding authority on safety.

B. Never abandon ship at night in Force 7 conditions. Wait until daylight and improved conditions before giving the abandon ship order regardless of the fire severity.

C. Call the company for authorisation before abandoning ship. The ISM Code requires management approval for the decision to abandon.

D. The Chief Officer makes the abandon ship decision — the master should remain on the bridge to coordinate communications with the coast guard until the last moment.

A. COMMERCIAL PRESSURE vs SAFETY — Master's authority: (1) GM ASSESSMENT: 0.25m GM with containers and a Force 9 forecast must be assessed against the IS Code minimum (0.15m) AND the practical performance of the vessel in Force 9 (7-10m seas). While 0.25m exceeds the IS Code minimum, it provides very limited stability reserve in severe conditions with heavy rolling. A stability improvement should be sought — low ballasting, removal of topweight — before departure; (2) MASTER'S AUTHORITY: SOLAS V Rule 34.3 — the master's judgement on safety shall not be overridden by the owner, charterer, or any other person. ISM Code Ch 5.2 — overriding authority explicitly confirmed; (3) LEGAL POSITION: if the master departs under commercial pressure with an inadequate GM and the vessel capsizes, the master faces criminal negligence charges (MSA 1995 s.58 — operating in an unsafe manner). "I was told to go" is not a defence; (4) COMMUNICATION: document all communications — email/telex the charterer stating the reasons for delay and the decision. This creates an evidence trail; notify the company and DPA of the commercial pressure and safety concern; (5) STCW VIII/2: the master has the right to make decisions for the safety of the vessel and crew without interference; (6) DECISION: do not depart. Improve stability first. Reassess the departure weather window.

B. Depart as demanded. The charterer bears responsibility for any voyage where they demand departure — the master is indemnified by complying with charterer instructions.

C. Compromise: depart with the current stability but reduce speed to 5 knots. This reduces rolling and compensates for the low GM.

D. SOLAS stability criteria apply only to the departure condition. Once at sea, weather conditions may change and reduce the risk — the departure decision is solely commercial.