Search and Rescue Operations

The Rescue Coordination Center (RCC) is the primary shore-based authority responsible for coordinating all search and rescue operations within a defined SAR region. In the United States, the USCG operates two RCCs — one in Norfolk, Virginia, covering the Atlantic, and one in Alameda, California, covering the Pacific. The RCC receives distress alerts via EPIRB, DSC, satellite, and voice reports, then assigns resources, designates the On-Scene Commander, and maintains oversight of the SAR mission until survivors are recovered or the search is suspended. Maritime RCCs are specifically called MRCCs (Maritime Rescue Coordination Centers). All vessels and aircraft involved in a SAR operation report to and take direction from the RCC/MRCC.

The International Aeronautical and Maritime Search and Rescue (IAMSAR) Manual is the joint publication of the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) that establishes the global framework for SAR operations. It consists of three volumes: Volume I covers Organization and Management, Volume II covers Mission Co-ordination, and Volume III covers Mobile Facilities (the on-board reference carried by ships and aircraft). The USCG exam tests candidates on SAR search patterns, datum calculations, and OSC duties — all of which are defined within the IAMSAR framework. Understanding IAMSAR means understanding the terminology, command structure, and operational procedures that govern every SAR mission.

The expanding square search (VS pattern) starts at the datum — the most probable location of the search object — and searches outward in an ever-widening square spiral. The searching vessel proceeds a set track spacing distance, turns 90 degrees, proceeds the same distance, turns 90 degrees again, then increases the leg length by one track spacing. This pattern provides thorough coverage near the datum and is used when the datum is well-defined but there is some uncertainty about the object's position. It is most effective for a single vessel searching a relatively small area. The track spacing (S) depends on the sweep width of the search resource, which varies by target type, sea state, and visibility.

A sector search (rotating sector or VS sector) is used when the datum is highly accurate and the search area is small — for example, when a distress position was transmitted by GPS with high confidence. The searching vessel departs datum on a magnetic bearing, searches outward a set distance, returns to datum, turns 120 degrees, searches again, returns, turns 120 degrees again, and completes the third leg. This creates three overlapping pie slices covering a 360-degree area. The sector search maximizes coverage of the highest-probability position. It is not suitable for large areas or when the datum has significant uncertainty.

A parallel track search (PS pattern) divides the search area into a rectangular grid and assigns a vessel or aircraft to search parallel legs separated by a uniform track spacing. All legs run in the same direction. This pattern is efficient for large, well-defined search areas and for multiple resources coordinated by a coordinator. A creeping line search (CS pattern) is structurally identical — parallel legs at uniform spacing — but the legs are oriented perpendicular to the direction of probable drift. The creeping line is preferred when the search object is believed to be drifting, because the search progresses across the drift direction rather than along it, reducing the chance of following a moving target.

A trackline return search (TL) is used when a vessel or aircraft has disappeared along a known route — for example, a vessel that failed to arrive at a destination and whose last known track is known. The searching resource follows the missing vessel's last known track outward from the departure point, then returns along the same track (trackline return), or searches parallel to the original track on the return leg (trackline non-return). This pattern is efficient when the search area is linear rather than a point or box.

Datum is the most probable position of the search object at the time the search is being conducted. It is calculated from the Last Known Position (LKP) by applying total drift over the elapsed time since the LKP was established. Total drift is the vector sum of leeway (wind-driven movement) and current set and drift. Leeway is expressed in knots and depends on the height of the object above the waterline. Set is the direction toward which the current is flowing, and drift is its speed in knots. Datum shifts continuously as time passes, so SAR coordinators recalculate datum throughout the operation to reposition search areas accordingly.

Leeway is the downwind movement of a vessel or person in the water caused by wind acting on the portion of the object above the waterline. It is measured in knots and acts in the downwind direction. A person in the water (PIW) with minimal windage has leeway of roughly 3 percent of wind speed. A life raft with a canopy may have leeway of 5 to 8 percent of wind speed or more. Leeway is combined vectorially with the current to produce total drift, which is applied to the LKP over the elapsed time to compute datum. SAR planners must account for leeway because a datum based only on current will underestimate how far downwind the object has traveled.

The On-Scene Commander (OSC) is the person designated by the SAR coordinator (RCC/MRCC) to control and coordinate SAR efforts at the scene. The OSC is typically the captain of the first vessel to arrive at the scene, or the most capable resource present. OSC duties include: establishing communications with the RCC; determining and broadcasting datum, search area boundaries, and search patterns; coordinating the movements of all surface and air assets on scene; establishing a common VHF working channel; managing lookout assignments; reporting search results to the RCC after each leg; maintaining a log of positions, times, and observations; and coordinating survivor recovery and medical care. The OSC continues in the role until relieved by the RCC or a more capable coordinator arrives on scene.

SOLAS Chapter V, Regulation 33 requires the master of any vessel at sea, upon receiving information that persons are in distress at sea, to proceed with all speed to their assistance. This duty applies regardless of nationality, flag state, or circumstances. Under U.S. law, 46 USC 2304 imposes essentially the same requirement: the master of any vessel must render assistance to any individual found at sea in danger of being lost, as long as rendering assistance does not seriously endanger the vessel, crew, or passengers. Failure to comply without justification is a federal crime punishable by a civil penalty.

COLREGS Annex IV lists: (1) Gun or explosive at one-minute intervals; (2) Continuous fog-signaling apparatus; (3) Rockets or shells throwing red stars; (4) SOS in Morse code by any means; (5) Spoken word MAYDAY by radiotelephony; (6) International Code Signal N over C; (7) Square flag with a ball above or below; (8) Flames on the vessel; (9) Rocket parachute flare or hand flare showing red light; (10) Orange smoke signal; (11) Slowly and repeatedly raising and lowering outstretched arms; (12) Radiotelegraph alarm signal; (13) Radiotelephone alarm signal; (14) Signals from EPIRBs; (15) Signals from radio communications systems including SARTs; (16) High-intensity white light flashing 50 to 70 times per minute.

A Search and Rescue Transponder (SART) responds to interrogation by X-band (9 GHz) ship and aircraft radar. When swept by a radar beam, the SART transmits a series of 12 sweeps that appear on the PPI display as 12 equally spaced dots radiating outward from the SART position. The innermost dot marks the actual position. At ranges within about 1 nautical mile, the dots broaden into arcs. A SART can be detected by ship radar at approximately 5 nautical miles and by aircraft radar at up to 40 nautical miles. The SART also emits an audible or visual alarm when interrogated, alerting survivors that a radar-equipped vessel is nearby.

An Emergency Position-Indicating Radio Beacon (EPIRB) transmits a digital distress signal on 406 MHz to the COSPAS-SARSAT satellite network, which relays the alert and position to the appropriate MRCC. Category I EPIRBs activate automatically when submerged in water to a depth of 1 to 4 meters. Category II EPIRBs are manually activated. All 406 MHz EPIRBs should be registered with the NOAA EPIRB Registry so the USCG can identify the vessel without delay. Many modern EPIRBs incorporate an internal GPS receiver that transmits the vessel's GPS position with the distress alert, reducing the search area dramatically.

When operating with aircraft in a SAR area, the vessel should: establish VHF communications on Channel 16 initially, then shift to a working channel as directed; advise the aircraft of position, course, speed, and search area; maintain steady course and speed during search legs; keep personnel clear of the hoist area when a helicopter approaches; position the vessel into the wind at slowest safe speed for hoist operations; and never touch a rescue hoist line or basket until it has grounded on the deck to discharge static electricity. The OSC coordinates surface and air track assignments to prevent gaps or overlap in coverage.

When recovering survivors from the water, approach from downwind and downcurrent so the vessel does not drift over the survivor. Stop engines before the survivor reaches the hull. After recovering survivors: (1) Keep survivors horizontal during recovery to prevent circulatory collapse from orthostatic shock. (2) Remove wet clothing carefully — cut if needed. (3) Wrap in blankets and cover the head. (4) Do not rub extremities — this drives cold blood to the core and worsens hypothermia. (5) Provide warm beverages if the survivor is conscious and able to swallow. (6) Monitor for cardiac arrhythmia and be prepared to perform CPR. (7) Advise the USCG and request medevac if the survivor is severely hypothermic or unconscious.

To report a distress on VHF: (1) Select Channel 16. (2) Transmit MAYDAY MAYDAY MAYDAY for life-threatening emergencies, or PAN-PAN PAN-PAN PAN-PAN for urgent non-life-threatening situations. (3) Identify your vessel by name three times. (4) State your position as precisely as possible. (5) Describe the nature of the distress, number of persons aboard, vessel type and color. (6) If equipped with a DSC VHF radio, first press the distress button to transmit a digital alert on Channel 70, then make the voice Mayday on 16. If no response is received within one minute, repeat the full transmission. The USCG will acknowledge and typically shift you to Channel 22A for working communications.