Search and Rescue Obligations for Merchant Ships

The law does not ask whether it is convenient.
It asks whether the ship was there and whether it went.

Introduction

Every master who has stood a bridge watch long enough has received a distress alert or heard one relayed by an MRCC. Most are resolved before any decision is required. Some are not. The ones that are not resolved by someone else are the ones that define whether a master understands what the law actually says — as opposed to what a pre-departure safety briefing implied it said.

The obligation to render assistance is not a discretionary act of seamanship. It is a binding duty under international law, codified in two instruments that sit above company procedures and commercial pressure alike. SOLAS Chapter V Regulation 33 and UNCLOS Article 98 together create an obligation that attaches to the ship and its master personally. The commercial cost of deviation is a recoverable expense. The cost of failing to deviate is not recoverable by any means.

What follows is not a reproduction of IAMSAR Volume III. Any bridge should already carry that document. This article addresses the obligations as they fall on a merchant master in practice: what triggers them, how coordination works, what the OSC role involves when it lands on the ship, what search patterns mean at command level, and how the record of the response is constructed afterwards — because afterwards is when it matters most.

Contents

• 1. The Legal Foundation: SOLAS V/33 and UNCLOS Article 98
• 2. Receiving a Distress Alert: The First Three Minutes
• 3. Coordination with the MRCC and the Chain of Authority
• 4. The On-Scene Coordinator Role
• 5. Search Patterns: What the Master Needs to Understand
• 6. The Limits of the Obligation
• 7. Deviation, Commercial Pressure, and the Legal Reality
• 8. Reporting, Records, and Expense Recovery
• 9. Closing Reality

1. The Legal Foundation: SOLAS V/33 and UNCLOS Article 98

SOLAS Chapter V Regulation 33 places the obligation on the master directly. On receiving information from any source that persons are in distress at sea, the master is bound to proceed with all speed to render assistance. The language is unambiguous and the threshold is low: information from any source. It does not require a confirmed EPIRB signal or a formal SAR coordination message. A visual sighting, a radio call, a relay from another vessel — any of these is sufficient to engage the obligation.

UNCLOS Article 98 operates at state level but extends its reach to every ship flying that state’s flag. It requires flag states to ensure masters comply with the duty to render assistance, to render assistance to any person found at sea in danger of being lost, and to proceed with all possible speed to the rescue of persons in distress. The convergence of these two instruments means there is no gap in the obligation and no jurisdictional escape route.

The obligation exists regardless of the nationality of the persons in distress, regardless of the circumstances that placed them there, and regardless of the flag the distressed vessel may be flying. None of those factors are legally relevant at the point of response.

The flag of a migrant vessel does not change the nature of distress.

SOLAS V/33 does provide two conditions under which the master may consider himself released from the obligation: if he learns that assistance is no longer required, or if another ship has responded and that master concurs with the other ship’s master that it is unnecessary to proceed. Both releases require positive confirmation. Assumption is not a release.

2. Receiving a Distress Alert: The First Three Minutes

A distress alert on GMDSS — whether via DSC on VHF Channel 70, MF DSC, or an EPIRB relay through an MRCC — demands an immediate and structured response. The sequence is not complicated but it must be instinctive, because the bridge in the first minutes of a distress situation is rarely calm.

The first action is acknowledgement. On VHF DSC, the distress acknowledgement is transmitted on Channel 70. The voice response follows on Channel 16. If the alert is received by multiple vessels, the acknowledgement should not be transmitted immediately on MF or HF where the MRCC should be the first to acknowledge — transmitting prematurely on those bands can mask the MRCC’s response and create coordination confusion. IAMSAR Volume III is explicit on this point.

The master is called immediately. Not the OOW making a preliminary assessment and then calling — the master is called at the moment the alert is received. Whatever else happens in those first minutes, the command position must be occupied by the right person.

Position, course, and speed of the distressed vessel or the last known position of the EPIRB are plotted at once. The ship’s own position, course, speed, and estimated time of arrival at the distress position are calculated. Weather and sea state at the distress position are assessed. All of this information is needed for the MRCC call, which follows quickly.

A distress alert is not a notification. It is a demand for a decision.

3. Coordination with the MRCC and the Chain of Authority

The MRCC is the competent authority for SAR coordination within its region. Contact should be established on the appropriate working frequency — not Channel 16 for protracted coordination, but on a designated working channel as directed. The master provides the ship’s identity, position, speed, ETA to the distress position, and any additional information that may assist the MRCC’s coordination picture.

The MRCC will typically have more information than the responding ship. They may already be coordinating an air asset, have contact with the distressed vessel, or have other ships in the area with better positions. They may also be working with incomplete information. Neither situation removes the master’s obligation to proceed until formally released or redirected.

Authority on scene is a separate matter from MRCC coordination. The MRCC directs the overall SAR operation. On-scene authority rests with whoever is designated as the On-Scene Coordinator. These are not the same role and the distinction matters operationally.

Channel 16 remains the distress and safety frequency. It is monitored continuously. Scene coordination between ships is usually conducted on a designated on-scene coordination frequency, typically Channel 6 or as assigned by the MRCC. Frequency discipline on scene is not optional — a crowded Channel 16 during a multi-vessel SAR response is a hazard in itself.

4. The On-Scene Coordinator Role

The OSC is responsible for coordinating the search and rescue effort at the scene. The role may be assigned by the MRCC or it may default to the first vessel on scene in the absence of a dedicated SAR unit. A merchant master who arrives first, in the absence of any state SAR asset, is the OSC by default. This is not a role that can be declined on the basis of unfamiliarity with the procedures.

The OSC’s responsibilities include establishing communications with all assisting ships and aircraft, coordinating search patterns, reporting to the MRCC, and managing the transition to rescue and recovery once survivors or wreckage are located. With aircraft involved, the OSC manages on-scene coordination including providing weather and sea state to inbound aircraft and designating safe transit altitudes if necessary.

IAMSAR Volume III contains the OSC checklist in full. It should not be read for the first time when the ship is already on scene. The key point for a master who inherits the role is that the MRCC remains the superior authority — the OSC executes on scene, but significant decisions are referred back to the MRCC rather than taken unilaterally.

When a dedicated maritime rescue coordination unit or a naval or coastguard vessel arrives on scene, the OSC function is normally transferred. The handover is a formal communication, not an informal assumption. Until that transfer is confirmed, the merchant master retains the responsibility.

No maritime authority will accept “I assumed someone else had taken over” as an account of how the coordination lapsed.

5. Search Patterns: What the Master Needs to Understand

A master directing a search does not need to compute drift models or calculate probability of detection curves — that is MRCC and SAR coordinator work. The master needs to understand what each pattern achieves, what its preconditions are, and where it breaks down. Receiving a search pattern assignment without understanding its logic is a way to execute it incorrectly.

The expanding square search begins at the datum — the last known or estimated position of the search object — and works outward in an expanding square track, with each leg extending by one track spacing relative to the previous. It concentrates effort on the highest-probability area and is appropriate when the datum is reasonably well established. Its weakness is that it covers ground slowly and the initial datum confidence must be high. If the datum is poorly constrained, time spent on an expanding square is time lost.

The sector search also works from a datum and is used when the datum is known with high confidence and the object is likely within a small radius. Three ships can conduct it simultaneously, each assigned a 120-degree sector. It is efficient for a small, well-defined area but is heavily dependent on datum quality.

The parallel track search is the workhorse of large-area searches. Ships or aircraft sweep parallel courses separated by a track spacing derived from the estimated sweep width — a function of visibility, sea state, and the nature of the search object. It is assigned when the datum is uncertain or the search area is large. The key operational discipline is maintaining the assigned track spacing and speed with precision. A ship that cuts corners or drifts off track creates gaps that the probability model does not account for.

Search pattern assignments come from the MRCC with a start point, track spacing, search speed, and course. The master executes the assigned pattern. Improvisation on pattern geometry during a coordinated multi-ship search creates overlap and gaps simultaneously and degrades the mathematical basis on which the MRCC is estimating coverage.

Visibility, leeway, current, and the nature of the search object — a life raft presents very differently from a person in the water — all affect what the ship can realistically detect. These conditions should be reported to the MRCC honestly, not optimistically. An overstated sweep width produces a false sense of coverage.

6. The Limits of the Obligation

The obligation to render assistance is not unlimited. SOLAS V/33 qualifies the duty with the words “without serious danger to the ship, the crew, or the passengers.” This qualification exists. It is narrow.

A master who declines to respond or withdraws from a SAR operation on the basis of danger to the ship bears the burden of demonstrating that the danger was genuine, serious, and not merely speculative or commercially inconvenient. Heavy weather that makes rescue difficult does not constitute serious danger to the ship in most circumstances. The threshold is considerably higher than discomfort or operational difficulty.

The qualification has been tested in courts and in flag state investigations. Masters who have cited danger as a reason for non-response and been found to have overstated the risk have faced serious consequences. The test is objective, not subjective.

There is no provision in SOLAS V/33 or UNCLOS Article 98 that releases a master from the obligation on the basis of cargo priority, charter party requirements, port window limitations, or the immigration status of persons in distress. These considerations are irrelevant to the legal obligation at the moment of response. They may have commercial consequences. They do not alter the law.

7. Deviation, Commercial Pressure, and the Legal Reality

Every deviation for SAR has a commercial cost. Fuel, time, port scheduling, demurrage exposure, charter party clauses — the list is familiar to any master who has had to make the call. The commercial pressure is real. It is also, in legal terms, entirely beside the point.

Cases in which masters have deviated for SAR and faced commercial challenge afterwards are rare and have generally not succeeded. P&I Clubs have well-established procedures for handling the costs and liabilities arising from SAR responses. Deviation to render assistance is covered under both the SAR framework and, in most jurisdictions, under the provisions governing deviation for humanitarian purposes in voyage charterparties. The commercial risk is smaller than it is sometimes presented to be.

Cases in which masters have failed to deviate and subsequently faced investigation are a different matter. The criminal exposure for a master who fails to render assistance and who cannot demonstrate that assistance was genuinely unnecessary or that serious danger to the ship existed is significant. Several flag states treat it as a serious criminal offence. Detention of the vessel is possible. The master’s certificate is at risk.

The deviation that was made will be examined. The deviation that was not made will be prosecuted.

Company instructions that conflict with the master’s legal obligation to render assistance are not a defence. A master who follows a company instruction not to deviate — and who allows persons to die as a result — does not escape liability by pointing to the instruction. The obligation is personal and it is statutory.

8. Reporting, Records, and Expense Recovery

The report to the MRCC during the SAR response is operational. The report that follows its conclusion is different in character — it is the documentary record on which subsequent legal, administrative, and commercial proceedings will depend.

The master’s log entries covering the SAR response should be detailed and contemporaneous. Position at the time the distress alert was received, the source and content of the alert, all communications with the MRCC and other vessels, the course and speed changes made, the time of arrival on scene, the conditions encountered, the survivors or casualties found, the time of departure from scene, and the reason for departure — all of this belongs in the record. Gaps in the log are not neutral. They are exploitable.

A separate SAR report should be completed using the format provided in IAMSAR Volume III, Appendix J. This is distinct from the official log entry and is submitted to the MRCC and, where required, to the flag state. The MRCC uses these reports to evaluate the response and to improve future SAR planning. They also form part of the official record of the event.

Expense recovery for SAR deviation is available in principle under the SAR Convention framework and under various national schemes. In practice, recovery is partial and variable. The P&I Club should be notified at the earliest opportunity — during the deviation, not after arrival. The Club can advise on preservation of the expense claim, what documentation to collect, and how to handle any commercial counterparty challenges.

Fuel costs, port costs arising from delay, survey fees for any damage sustained during the rescue, medical expenses for survivors taken aboard, and crew overtime are typically recoverable categories. The claim needs supporting documentation — log entries, fuel records, communications logs, medical records. None of this documentation is reconstructed adequately from memory after the fact.

Survivors taken aboard create their own administrative obligation. Disembarkation in a place of safety is the guiding principle of the SAR Convention. What constitutes a place of safety is not simply the nearest port. The MRCC coordinates disembarkation, but the master has a voice in this decision and should engage the MRCC on it early. The ship’s flag state and the P&I Club are also relevant contacts where the disembarkation situation is complex — particularly if the survivors are migrants in legally contested circumstances.

9. Closing Reality

The legal obligation to render assistance does not depend on certainty, on confirmation, on commercial approval, or on the identity of the persons in distress. It depends on the ship being there and on the master knowing what the law requires of him.

IAMSAR Volume III sits on the bridge. SOLAS is carried as part of the ship’s statutory documentation. The framework exists and it is not complicated. What creates failure is not ignorance of the rule — it is the moment of hesitation when the charter party, the schedule, or the phone call from the office suggests that someone else will handle it.

Someone else will not always handle it.

The obligation is not discharged by hoping another ship is closer.