Your vessel is operating in Antarctic waters south of 60°S. Your chief engineer advises that the vessel's HFO tank needs to be filled from ship's stores to maintain the heating system for ballast tanks. What are the Polar Code environmental restrictions?

A. POLAR CODE ENVIRONMENTAL RESTRICTIONS — ANTARCTIC AREA: MARPOL ANNEX I REGULATION 43A — HFO BAN IN ANTARCTIC: Regulation 43A (in force since 1 August 2011) prohibits: (a) The USE as fuel of heavy fuel oil (HFO) south of 60°S latitude; (b) The CARRIAGE in bulk as fuel of HFO south of 60°S latitude. HFO is defined as oil with a density > 900 kg/m³ at 15°C or a kinematic viscosity > 180 mm²/s at 50°C. HEATING BALLAST TANKS: if the vessel uses HFO for the main engine or auxiliary heating systems south of 60°S — this is a MARPOL Annex I Reg 43A violation. HFO may NOT be transferred from storage tanks for any operational purpose in Antarctic waters. WHAT DOES THIS MEAN PRACTICALLY?: (1) Vessels operating south of 60°S must switch to LSFO (low-sulphur fuel oil) or MDO/MGO before entering the Antarctic zone; (2) HFO tanks must be empty or isolated (not connected to operational fuel systems) while south of 60°S; (3) The ballast tank heating system must be capable of using MGO/LSFO if polar operations are planned; POLAR CODE (MARPOL ANNEX I CHAPTER 10, REG 43): the Polar Code adds further restrictions including: (a) No discharge of oil or oily mixtures in polar waters (stricter than non-polar MARPOL); (b) No discharge of noxious liquid substances in Category X, Y in Arctic/Antarctic; (c) No incineration in polar waters. CONSEQUENCES OF VIOLATION: MARPOL violation in Antarctica — flag state prosecution, potential action by Antarctic Treaty nations (Australia, UK, NZ, Norway, etc.) under their domestic law.

B. The HFO ban applies only to tankers carrying HFO as cargo. General cargo ships and bulk carriers can use HFO as bunker fuel south of 60°S.

C. The Antarctic HFO ban is a soft law convention. As the vessel is not near any Antarctic territorial waters, the regulations are advisory only.

D. If the HFO is needed for safety reasons (preventing freezing of ballast water), the master can use it under ISM Code overriding authority.

A. PASSAGE PLAN APPROVAL — MASTER'S SOLAS V/34 OBLIGATIONS: SOLAS V/34 LEGAL REQUIREMENT: "Prior to proceeding to sea, the master shall ensure that the intended voyage has been planned using an appropriate chart and appropriate nautical publications for the area concerned, taking into account the guidelines and recommendations developed by the IMO." This is an absolute obligation on THE MASTER — not the chief officer. The master cannot delegate this legal responsibility. WHAT THE MASTER MUST VERIFY IN THE PASSAGE PLAN: (1) APPRAISAL: is the passage planned using the correct, up-to-date charts (latest edition, NTM corrections applied)? Have the relevant nautical publications been consulted (Sailing Directions, Light Lists, Tide Tables, NtM, Notices to Mariners)? Have weather routing service recommendations been considered?; (2) PLANNING: is the passage plan complete from berth to berth? Does it include: (a) waypoints with safe clearing bearings or distances; (b) no-go areas clearly marked; (c) abort points — where is the last point at which the vessel can safely alter to an alternative port?; (d) wheel-over positions for planned alterations?; (e) UKC calculations at minimum water depth points?; (f) speed calculations to ensure arrival at pilot station at the correct tidal window?; (3) EXECUTION CHECKS: are monitoring intervals appropriate to the waters transited? Are danger waypoint checks included?; (4) CONTINGENCY: is there a documented contingency plan for engine failure, medical emergency, severe weather forcing diversion?; (5) MASTER'S SIGN-OFF: the master must sign the passage plan, confirming approval. This signature carries legal weight.

B. SOLAS V/34 is fulfilled as long as a passage plan exists in any form. The master does not need to review the detail — that is the chief officer's responsibility.

C. Passage planning only applies to coastal and restricted waters. For an open-ocean transatlantic passage, a general course line and waypoints are sufficient compliance.

D. The master can delegate the legal obligation for passage planning to the chief officer. If the chief officer is competent, the master's review is optional.

A. UKC CALCULATION AND POLICY APPLICATION: BASIC UKC CALCULATION: Available water depth = Chart depth + Tidal height = 16.2 + 0.8 = 17.0m. Vessel draught = 14.5m. Static UKC = 17.0 - 14.5 = 2.5m. UKC policy requirement = 10% of draught = 1.45m. STATIC RESULT: 2.5m available vs 1.45m required — APPEARS SUFFICIENT. HOWEVER — THE MASTER MUST CONSIDER DYNAMIC UKC FACTORS: (1) SQUAT: at speed in shallow water, the vessel will "sink" relative to the water surface due to Bernoulli pressure reduction. For a vessel of this draught in 17m of water (h/d ratio = 17/14.5 = 1.17 — VERY SHALLOW), squat could be 0.5-1.0m at standard speeds. Use squat formula or company guidance; (2) HEEL ALLOWANCE: if the vessel is turning or wind-heeled, the draught at the low side increases. A 2° list or heel adds ~0.5m to draught at the side; (3) TIDE PREDICTION UNCERTAINTY: is the 0.8m tidal height taken from a standard tidal prediction? In practice, meteorological conditions can reduce tidal height significantly. A strong onshore wind can ADD height; an offshore wind can REDUCE it; (4) CHART DATUM UNCERTAINTY: is the 16.2m from a recent survey? Chart datum may differ from actual current depths in silting areas; (5) WAVE RESPONSE: in swells, the vessel pitches and the bow drops lower — "hogging/sagging" effects; DECISION: with static UKC of 2.5m against 1.45m required — the margin appears sufficient. But with squat at speed potentially 0.5-1.0m, the DYNAMIC UKC may be as low as 1.0-1.5m. If squat approaches 1.0m, the remaining dynamic UKC is 1.5m — which is at the policy limit. RECOMMENDATION: reduce speed to minimise squat, use VHF confirmation of current tidal height, arrive at the shallowest point at maximum tidal height.

B. Static UKC of 2.5m exceeds the 1.45m policy requirement. Proceed at full speed — there are no further calculations required.

C. The 10% policy gives 1.45m minimum UKC. As the static UKC is 2.5m — there is more than adequate margin for all conditions. Squat is only relevant for small vessel operations.

D. Tidal height of only 0.8m is insufficient. Wait for high water (which adds significantly more height) before attempting the passage.