Search and Rescue Coordination

Prerequisites

This lesson is part of the RYA/MCA Yachtmaster Offshore syllabus. You should already:

• Hold the SRC and be able to send and receive DSC alerts and voice Mayday, Pan-Pan and Securité messages (GMDSS lesson earlier in this course).
• Know how EPIRBs, PLBs and SARTs work (Abandon Ship lesson).
• Be competent at chartwork: plotting positions, applying tidal streams, working up EPs and courses to steer.
• Be able to carry out man overboard recovery under sail and power, which the Yachtmaster Offshore exam tests in practice.

Learning Objectives

By the end of this lesson you should be able to:

• Describe the international and UK SAR organisation: MRCCs, SAR mission coordinators, on-scene coordinators and the IAMSAR Manual.
• Explain how distress alerts reach rescue authorities by DSC, EPIRB and voice, and the priority of distress, urgency and safety messages.
• State a skipper's legal duty to assist and how to respond to a distress alert.
• Calculate a search datum allowing for current and leeway, and update it with time.
• Carry out expanding square, sector and parallel sweep search patterns.
• Act as on-scene coordinator if required and send a SITREP to the MRCC.
• Recover survivors safely and work with SAR helicopters.
• Map your knowledge to the RYA Yachtmaster Offshore syllabus (G158): the emergency situations and search and rescue sections, including responding to distress alerts, the duty to assist, the roles of the MRCC and the On-Scene Coordinator, the IAMSAR Manual Volume III search patterns, man overboard and survivor recovery, helicopter operations and the radio procedures for Mayday relay, as the examiner expects them in the oral and practical parts of the exam.
• Send and acknowledge Mayday and Mayday Relay messages with the correct format.
• Keep a search log and plot of the area covered, and brief the crew as lookouts.

The Duty to Assist

SOLAS Chapter V Regulation 33 and UNCLOS Article 98 require the master or skipper of any vessel at sea who receives information that persons are in distress to proceed with all speed to their assistance, if able to do so without serious danger to their own vessel and crew. In the UK this applies to pleasure craft as well, through the Merchant Shipping (Safety of Navigation) Regulations. If you decide not to go, you must log the reason and, if possible, inform the rescue authority. You are released from the obligation if the rescue authority tells you that you are not needed.

A small yacht's main contributions are usually: relaying a distress, being first on scene, keeping a lookout, marking the position and recovering a small number of survivors. Recognise your limitations: in heavy weather a 12 m yacht may be unable to recover people safely from the water, but can still mark the position and report.

The SAR Organisation

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The world's oceans are divided into Search and Rescue Regions (SRRs), each the responsibility of a state. Each SRR has a Rescue Coordination Centre: for maritime SAR, a Maritime Rescue Coordination Centre (MRCC), or a Joint Rescue Coordination Centre (JRCC) where air and sea are combined.

In the UK, HM Coastguard runs the national network from the National Maritime Operations Centre (NMOC) at Fareham and a number of coordination centres around the coast. The coastguard tasks:

• RNLI and independent lifeboats;
• coastguard search and rescue helicopters;
• coastguard rescue teams on the shore;
• any ship or yacht that can help, including commercial ships through the ship reporting systems.

The IAMSAR Manual (International Aeronautical and Maritime Search and Rescue) sets the procedures. Volume I covers organisation, Volume II mission coordination and Volume III mobile facilities. Volume III must be carried by SOLAS ships and is the volume relevant to a skipper.

Two key roles:

• SAR Mission Coordinator (SMC): the person in the MRCC in charge of the incident, who works out the search area and tasks resources.
• On-Scene Coordinator (OSC): a unit at the scene designated to coordinate the assets there. This is often a lifeboat, warship or large ship, but in the first stages may be whoever is first on scene.

How Distress Alerts Flow

Message Priority

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A Mayday has absolute priority. Every station hearing it must stop transmitting anything that might interfere and listen. When the MRCC imposes radio silence with "Seelonce Mayday", only the casualty and stations involved may transmit.

DSC Alerts

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A DSC distress alert on VHF Channel 70 reaches every DSC-equipped station in range: the coastguard and nearby vessels. It contains the MMSI, position, time and nature of distress if selected. The vessel then follows with a voice Mayday on Channel 16.

If you receive a DSC distress alert on a yacht:

1. Listen on Channel 16 for the voice Mayday and wait about 5 minutes. The coast station normally acknowledges first.
2. If the coastguard acknowledges, note the details and position and listen.
3. If there is no acknowledgement and you are in a position to help, acknowledge by voice on Channel 16 and tell the coastguard by any means.
4. Do not relay a DSC distress alert by DSC (a "DSC relay") unless instructed by the coastguard, or you know the casualty is in distress and no coast station has acknowledged. Unnecessary DSC relays cause confusion.
5. Plot the position, work out a course and ETA, and log everything with times.

EPIRB Alerts

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A 406 MHz EPIRB is detected by Cospas-Sarsat satellites in low earth orbit (LEOSAR), geostationary orbit (GEOSAR) and, more recently, medium earth orbit (MEOSAR). The signal passes to a ground station (LUT, Local User Terminal), then to a Mission Control Centre, and on to the MRCC responsible for the area. The MRCC uses the beacon's registration to identify the vessel and contact the emergency contact ashore, and tasks rescue units. The 121.5 MHz homing signal guides them in for the final approach.

Worked Timeline

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The sequence above shows how quickly a well-handled alert can lead to rescue. Note the order: DSC alert, EPIRB, voice Mayday, MRCC acknowledgement and tasking, a broadcast to other ships, the nearest vessel proceeding and taking the OSC role until relieved, then the helicopter.

Liaising With the Coastguard

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If you are proceeding to assist, call the MRCC, give your vessel name, position, ETA, persons on board, capabilities (for example "sailing yacht, 4 crew, can recover 2 survivors, no medical facilities") and follow their instructions. Never start an independent search without telling the MRCC: your effort must fit into their plan.

A SITREP (situation report) is sent from the scene to the MRCC at intervals. It typically contains:

• identity of the OSC or reporting vessel and position;
• the situation: what has been seen, found or recovered;
• weather on scene: wind, sea, visibility;
• search pattern in use, area covered and track spacing;
• units on scene;
• results so far;
• future intentions;
• assistance needed.

The first SITREP should be sent as soon as possible after arrival; later ones whenever something changes, or as agreed with the MRCC.

The On-Scene Coordinator

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If you are first on scene and the MRCC has not designated anyone else, you may need to act as OSC until a better-equipped unit arrives. The OSC:

• keeps in contact with the MRCC and sends SITREPs;
• allocates search areas or patterns to vessels as they arrive, to avoid duplication and collision;
• keeps a plot of what has been searched;
• coordinates communications on a working channel agreed with the MRCC;
• hands over to a lifeboat or other unit when it arrives, briefing them on what has been done.

In practice a yacht will usually hand over to an RNLI lifeboat or a ship quickly, but the first hour matters: survival time in cold water is short.

Working Out the Datum

The datum is the most probable position of the target at a given time. It is where you start the search.

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Start from the last known position (LKP), for example the position given in the Mayday or where a man went overboard. Then allow for:

• Total water current: the tidal stream plus any ocean current and wind-driven current. A person in the water and a liferaft move with the water.
• Leeway: the target's own movement downwind through the water due to wind on its exposed parts. A person in the water has very little leeway; a liferaft without a drogue has a lot. IAMSAR Volume III gives typical values. As a rough guide: person in the water about 0 to 2% of wind speed; liferaft with drogue about 3 to 4%; liferaft without drogue 5 to 7% or more; capsized yacht about 2 to 3%.

Datum = LKP plus (current vector x time) plus (leeway vector x time).

Worked Example

A man overboard was reported at 1000 at position A. You arrive at 1130. The tidal stream is setting 090°T at 1.5 kn. The wind is from 270° at 20 kn, so leeway blows toward 090°T. The casualty is in a lifejacket: take leeway as about 1% of the wind, so 0.2 kn.

• Time elapsed: 1.5 hours.
• Current drift: 1.5 kn x 1.5 h = 2.25 miles toward 090°T.
• Leeway drift: 0.2 kn x 1.5 h = 0.3 miles toward 090°T.
• Total drift: about 2.6 miles toward 090°T.

The datum at 1130 is 2.6 miles east of A. If the stream had been running at 90° to the wind, you would add the two vectors on the chart instead. Notice that searching at A would have been 2.6 miles in the wrong place.

Updating the Datum

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The datum moves with time. Recalculate it at intervals (every hour or at each change of tidal stream), and whenever new wind or current information becomes available. Mark each datum as a waypoint on the plotter and chart so that the trail shows the drift. Always start or restart the search at the latest datum, not the LKP. When the tide turns, the drift reverses: a casualty may come back towards the LKP.

Search Patterns

IAMSAR Volume III describes standard patterns. Track spacing (S) depends on visibility, sea state, target size and the height of eye of the lookouts. For a person in the water searched from a yacht, S may be as little as 0.1 to 0.3 miles; for a liferaft in good visibility, perhaps 1 to 2 miles.

Expanding Square

Used when the datum is known fairly accurately and the search area is small. It is the most common pattern for a single yacht.

1. Start at the datum.
2. Steer the first leg of length S, usually directly into the wind (or as told by the MRCC).
3. Turn 90° (always the same direction, e.g. to starboard) and steer a second leg of S.
4. Turn 90° and steer 2S, then 90° and 2S.
5. Continue: 3S, 3S, 4S, 4S and so on.

Example with S = 0.2 miles at 5 kn: legs of 0.2, 0.2, 0.4, 0.4, 0.6, 0.6 miles take about 2.4, 2.4, 4.8, 4.8, 7.2, 7.2 minutes. Accurate course and timing are essential, so use a stopwatch and the plotter and allow for the current, which carries the whole pattern with the target.

Sector Search

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Used when the datum is accurate and the area small, for example a man overboard seen to go in or a position from a PLB. The pattern is a series of legs out from and back through the datum, with 120° turns to starboard after each leg. A full pattern of nine legs covers the circle in three triangles; then the whole pattern can be repeated rotated by 30°.

Leg length for a person in the water is often 0.5 to 2 miles, depending on visibility. The datum should be marked with a dan buoy or smoke float so that the pattern can be re-centred as it drifts.

Parallel Sweep

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Used for large areas when the position is uncertain, usually with several vessels in line abreast, each separated by the track spacing S. The legs run parallel to the long side of the search area, and the vessels turn together at the end of each leg. It is mostly run by the OSC with ships and lifeboats; a yacht taking part keeps strictly to its allocated track and spacing.

Choosing a Pattern

Recovering Survivors

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• Approach so that the survivor ends up in your lee, sheltered by the yacht from wind and sea. Under power, approach slowly with the survivor on the leeward side and stop to windward of them, so the yacht drifts towards them rather than away. Keep the propeller well away from people in the water: stop it or put it in neutral when close.
• Get a line on them quickly, using a throwing line, lifebuoy or Lifesling.
• Lift them out using a halyard and lifting strop, a scrambling net, a recovery net or a parbuckle (Jason's Cradle). A short ladder is useless for a cold, exhausted person.
• Lift horizontally if possible. A hypothermic casualty lifted vertically may collapse because blood pools in the legs (post-rescue collapse). Two strops, one under the arms and one under the knees, help.
• Treat for hypothermia: handle gently, keep horizontal, shelter, remove wet clothes if you can keep them warm, wrap in blankets or a survival bag, give warm sweet drinks only if fully conscious. Get radio medical advice through the coastguard.
• Count heads, and report the numbers recovered to the MRCC.

Working With Helicopters

• Listen to the MRCC and the helicopter on the working channel (often Channel 16, 67 or as directed).
• Clear the deck of loose gear that might be blown away or tangle the winch wire. Lower or remove anything tall where possible.
• The pilot will usually ask you to steer a steady course with the wind about 30° on the port bow, at a steady speed, often 5 knots or as instructed. Sailing yachts are often asked to motor with sails down; sometimes the crew is asked to go into the liferaft or dinghy towed astern because the mast makes winching on deck dangerous.
• Let the winch wire or hi-line earth on the water or deck before touching it, to discharge static.
• Never secure the winch wire or hi-line to the boat.
• The winchman is in charge on deck; follow instructions.

Worked Example

Scenario. You are skipper of a 13 m yacht with 5 crew, 15 miles south of Start Point at 1500. You hear a DSC distress alert, then a voice Mayday: "Fishing vessel Morning Star, position 50°00'N 003°40'W, sinking, 3 persons abandoning to liferaft". No coastguard acknowledgement is heard. Wind SW Force 5, visibility good, tidal stream setting 070°T at 1 knot.

1. Plot. The casualty is 6 miles from you on 230°T. At 6 knots under power, ETA 1 hour.
2. Respond. Wait about a minute for the coast station, then acknowledge by voice: "Morning Star, this is yacht Tern, received Mayday, proceeding, ETA 1600". Call Falmouth Coastguard by voice to confirm they have the alert and offer assistance.
3. Coastguard instructions. The coastguard asks you to proceed and act as OSC until the Salcombe lifeboat arrives at about 1630.
4. Prepare. Brief crew. Lookouts allocated by sector, binoculars, recovery gear rigged, first aid and blankets ready, engine checked, log kept by a dedicated recorder.
5. Datum. LKP at 1500, raft without drogue, wind 20 kn from the SW so leeway about 5% x 20 = 1 kn towards 045°T. Current 1 kn to 070°T. At 1600, drift is roughly 2 miles towards about 058°T. The datum at 1600 is 2 miles NE of the LKP, closer to you than the LKP.
6. Search. You see nothing on arrival, so start an expanding square at the datum with S = 1 mile (raft, good visibility), sending a SITREP to the coastguard.
7. Find. At 1625 the bow lookout spots a red handheld flare. You find the raft, approach so it is in your lee, and recover the three crew by halyard and strop. One is cold and lethargic, so is lifted horizontally and treated for hypothermia.
8. Report and hand over. SITREP to the coastguard: "3 persons recovered, 1 hypothermic, liferaft at position ..." The lifeboat arrives, the hypothermic casualty is transferred, and the coastguard closes the incident.

What To Do When You Hear a Mayday: The Examiner's Checklist

If asked "what do you do if you hear a Mayday?", give a structured answer. Write it down in the same order each time:

1. Stop transmitting (except in answer) and listen. Write down what you hear: name and MMSI, position, nature of the distress, number of people, assistance required, time.
2. Plot the position on the chart or plotter immediately. Check it is plausible (is it on land?). Note the distance and bearing from you.
3. Wait and listen for a coastguard or ship acknowledgement. The coast station normally acknowledges within a minute or two.
4. Decide whether you can help without serious danger to your own vessel and crew. Consider your speed, the sea state, your fuel and crew experience and the distance.
5. Acknowledge (if there is no other acknowledgement and you can help), by voice on Channel 16, and tell the coastguard (see the script below).
6. Keep the log with times, positions, messages and decisions.
7. Prepare the boat and crew for the rescue: engine, lookouts, recovery gear, medical kit, lifejackets, briefing.
8. Keep in touch with the MRCC and follow the instructions of the SMC or OSC.

The voice procedures

The format of a Mayday message is fixed so that the key information is given in the same order every time.

Acknowledging a Mayday (only if no coast station has done so, and you can help): MAYDAY, vessel name of the casualty (three times), THIS IS, your own name (three times), RECEIVED MAYDAY. Then add your position, speed and ETA, number of persons, and what assistance you can give.

Mayday relay. If you know a vessel is in distress and she cannot transmit, or you have heard a Mayday and it has not been acknowledged, transmit: MAYDAY RELAY MAYDAY RELAY MAYDAY RELAY, ALL STATIONS (or the coastguard), THIS IS (your vessel name three times and MMSI), then repeat the original details: name, position, nature of distress, assistance needed, and any other information, followed by OVER. Only transmit a relay by voice and, if on DSC, follow the coastguard's instructions.

Radio silence. The coastguard or the casualty may impose silence on the distress frequency with SEELONCE MAYDAY (the word is the French silence). It is lifted by PRUDONCE (limited transmissions allowed) or SEELONCE FEENEE (distress traffic has ended). Never use any of these unless you are the casualty or the controlling station.

When you are the casualty, the same format applies. Send the DSC distress alert first if time allows, then the voice Mayday on Channel 16. Cancel any false alert at once by voice on Channel 16 (and by cancelling the DSC if your set can) and call the coastguard to confirm: a false alert can send a lifeboat and a helicopter to sea.

UK Organisation in Practice

In the UK the national centre is the National Maritime Operations Centre at Fareham. Calls to the coastguard come in by:

• DSC on VHF Channel 70, followed by voice on Channel 16 (the usual way from sea);
• 999 or 112 on a mobile phone ("Coastguard"), which should be used when you have a signal near the coast and you are not sure the radio has been heard;
• Cospas-Sarsat alerts from registered 406 MHz beacons.

HM Coastguard also runs the CG66 safety identification scheme: you can register your vessel details (including the MMSI, EPIRB and PLB identity, number of crew and a contact) at no cost. If you are overdue or a beacon activates, the coastguard knows who you are. Register your 406 MHz beacon (EPIRB, PLB) with the MCA beacon registry, and re-register it if you change the owner, the vessel or the contact numbers. A beacon with an unregistered identity may waste valuable hours in the response.

Search and rescue helicopters, lifeboats (RNLI and independent), coastguard rescue teams and the Royal Navy and RAF all work under the coastguard's tasking. Commercial ships and yachts may be asked to help by the same route, and the MRCC can call on ships in the area through AMVER (Automated Mutual-Assistance Vessel Rescue System) or equivalent ship reporting.

Survival Time and Why Speed Matters

The time available is the main driver of the whole search. Cold water kills in several stages:

• Cold shock in the first minute or two causes an involuntary gasp and rapid breathing, and can lead to drowning even in strong swimmers. A lifejacket and a spray hood help.
• Swim failure in the next 10 to 30 minutes, as arms and legs lose strength and coordination, so even a short swim to a boat or liferaft may be impossible.
• Hypothermia after 30 minutes or more. In UK waters the sea is 6 to 10 degrees C in winter and rarely above 17 degrees C in summer, so exhaustion and loss of consciousness can be expected within one to a few hours without protection.
• Post-rescue collapse can occur during or after recovery, even in a casualty who appears to be recovering.

A person in the water in 10 degrees C is, in broad terms, likely to be unable to help in their own rescue after about 30 to 60 minutes, and unlikely to survive more than a few hours. A lifejacket with a spray hood, a PLB, a whistle and a strobe light enormously raise the chance of being found. Those figures are why the first yacht on scene often makes the difference: acting in the first hour matters far more than a perfect search pattern two hours later.

Searching: Lookout Technique and Aids to Detection

Lookouts

The expanding square or sector search finds nothing if the lookouts do not see the target. Brief the crew before starting the pattern.

• Allocate a sector to each lookout (for example bow lookout covers 270 to 090 relative, port lookout 090 to 180, and so on) and a scan routine (look ahead and sweep slowly, do not stare at one spot).
• Use binoculars sparingly for confirmation; scan with the naked eye and then check suspicious spots with binoculars.
• Rotate lookouts every 15 to 20 minutes: concentration falls rapidly.
• Keep the sun behind the lookouts where possible. Glare on the water hides a small target.
• A person in the water, even in a lifejacket, is a head about 20 cm across at wave level. In a seaway, the target is visible only when it is on a crest. Slow down to 3 to 4 knots in the search, which gives more time to look.
• A recorder logs all sightings, times, and positions.

Signals and aids that help the searcher

The photograph below shows a typical 406 MHz EPIRB. It is the most important single alerting device on an offshore yacht: it transmits both a coded distress signal (identifying the registered vessel and, if fitted with GPS, her position) and a 121.5 MHz homing signal.

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Image: Marwan Mohamad, CC BY-SA 4.0, via Wikimedia Commons.jpg)

The photograph below shows SOLAS-type pyrotechnics: a handheld red flare, orange smoke signal and a parachute rocket. Use handheld flares and smoke for the final approach, once a rescuer is close, and keep the parachute rockets for the first alert. Hold flares to leeward and never point them at people or craft.

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Image: Christopher Doyle, CC BY-SA 3.0, via Wikimedia Commons

Searching at night and in poor visibility

• Use radar with the range scale set to 1 to 3 miles and reduce sea clutter carefully. A liferaft with a radar reflector gives a weak echo; a SART gives a strong signal.
• Slow down. A search at night at 3 knots with a spotlight sweep and lookouts out of the cabin lights (dark-adapted) is better than a fast, noisy pattern.
• Consider using a parachute flare to illuminate the area at the start, and tell the MRCC.
• Stop the engine periodically and listen for whistles or shouts.
• Drop a dan buoy or lit float at the datum so you have a visible reference while searching.

Further Datum Calculations

Worked example with vectors at an angle

A liferaft without a drogue was reported at position A (LKP) at 1000. You arrive at 1200. Tidal stream: 180 degrees at 1.0 knot. Wind: 16 knots from 270 degrees. The raft's leeway is 5 per cent of the wind speed, which is 0.8 knots, towards 090 degrees.

• Elapsed time: 2 hours.
• Drift by current: 1.0 x 2 = 2.0 miles towards 180 degrees (south).
• Drift by leeway: 0.8 x 2 = 1.6 miles towards 090 degrees (east).
• Combine as two sides of a right-angled triangle: 2.0 miles south, then 1.6 miles east.
• Distance from LKP = square root of (2.0 squared + 1.6 squared) = square root of 6.56 = about 2.6 miles.
• Bearing from LKP: the angle east of south is the arctangent of 1.6 divided by 2.0, about 39 degrees, so the datum lies on a bearing of 180 minus 39 = 141 degrees.

The datum at 1200 is therefore 2.6 miles from the LKP on a bearing of 141 degrees True. Plot it by drawing the tidal vector from A first, then the leeway vector from the end of it, as on the diagram earlier in this lesson, and join A to the end. Mark it on the chart or plotter as a waypoint named for the time (DATUM 1200).

Uncertainty and the size of the search area

No datum is exact. The error comes from three sources: the LKP itself (was it a GPS fix or an estimate?), the drift (how well do you know the wind and current?) and the navigation of the search vessel. Combine them sensibly: if the LKP is uncertain by 1 mile, the drift by 15 per cent of the 2.6 miles (about 0.4 miles) and your own navigation by 0.1 mile, the total probable error is roughly the square root of (1 squared + 0.4 squared + 0.1 squared), or about 1.1 miles. The first pass of an expanding square should therefore extend at least this far from the datum, and it is wise to cover more, in practice the area within about 1.5 to 2 times the total probable error. The coastguard (SMC) will use the IAMSAR computer tools and drift models to produce a search area; your datum and your search are the early action until those resources arrive.

Drift of a person in the water and common leeway values

Leeway depends on the object, its freeboard, the sea state and whether the drogue is deployed. The figures below are approximate and are based on IAMSAR Volume III tables; check the manual.

Leeway acts at an angle to the downwind direction, and a target may drift consistently to one side. Searchers treat the downwind direction as the centre and widen the area to both sides.

Track Spacing and Coverage

Track spacing S, the distance between adjacent legs, should not exceed the sweep width: the distance within which the lookouts are likely to see the target. IAMSAR Volume III has tables of uncorrected sweep widths. They depend on the target type, visibility, and the height of the lookouts' eyes. As an illustration only:

Correct for the weather: in a rough sea or poor visibility, reduce by a half or more. A track spacing equal to the sweep width gives a theoretical probability of detection of about 80 per cent on one pass; to improve, halve the spacing or repeat the pattern. When in doubt, use a smaller spacing: fewer gaps mean fewer people left behind.

Making the pattern accurate

• Use the plotter or GPS, with waypoints for each corner of the pattern, and set the autopilot only if the helmsman is also watching.
• Compute the time of each leg and note the start time; do not rely on GPS distance alone if the helm wanders.
• Allow for tide: the datum drifts and the whole pattern should drift with it. Either re-centre the pattern at regular intervals on the new datum, or move the waypoints.
• The first leg is usually directed into the wind (so that navigation errors tend to be corrected by leeway rather than accumulating).
• Turn in the same direction (usually to starboard so that the lookouts on the starboard side see the water just covered) and keep a log of the turn positions.

Worked example: expanding square with S = 0.2 nm at 5 knots

First leg due north, turning 90 degrees to starboard at the end of each leg.

After 48 minutes the yacht has run 4.0 miles and has searched a square about 1.6 miles across, centred on the datum. In that time the datum itself will have drifted with the tide (at 1 knot, 0.8 miles), so allow for it. If nothing is found, the square can be continued (legs of 1.0 mile, 1.0 mile and so on) or moved to a new datum.

Recovering a Casualty: Equipment and Method

The recovery is often the hardest part. A 12 tonne yacht with a free board of 1 m cannot lift a 90 kg person in a waterlogged jacket without a mechanical advantage. Choose the method before the emergency, and practise it.

1. Stop the boat close upwind or alongside and in the lee of the person, with the engine out of gear when the person is within a few metres of the propeller. Use the Lifesling or a heaving line thrown past them and then pulled back so that it lies across them.
2. Get a line on the person and the person secured to the yacht before attempting to lift. A person with a line round the chest under the arms and clipped to the boat cannot drift away.
3. Lift by one of the following:

• halyard to a lifting strop under the arms, taken to a winch (best): a spinnaker halyard with a block gives a 2:1 or 3:1 purchase;
• a lifting sling or parbuckle (a sail or net hung over the side and hauled in so that the person rolls up it);
• a lifesling rescue system with a halyard hoist;
• a boarding ladder, only for those who can climb themselves;
• a dinghy or liferaft alongside, which lowers the lift.

1. Treat for cold shock, hypothermia and injury once aboard (see the Medical Emergencies lesson). Keep the person horizontal and warm, and monitor the airway and breathing.
2. Tell the MRCC the number recovered and their condition, and ask for medical advice.

The photograph below shows a Lifesling: a floating loop with a long buoyant line trailed from the stern, and a lifting bridle. It allows a short-handed crew to circle the person, put the loop into their hands, and bring them alongside, ready for hoisting.

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Image: Dennis van Zuijlekom, CC BY-SA 2.0, via Wikimedia Commons.jpg)

Recovering from a liferaft

Survivors in a liferaft are usually safer where they are than they will be on your deck in a big sea. Tie your yacht alongside the raft in the lee, send a line and let them climb across one at a time if conditions are calm. In rough conditions, keep the raft on a long line on your lee side and move the survivors one at a time, strongest first, using a lifting strop. If helicopters are involved, they may prefer the survivors to remain in the raft.

Casualty care priorities

Follow ABC (airway, breathing, circulation) as taught in the First Aid course. Treat severe bleeding, then hypothermia. In particular:

• handle hypothermic casualties gently, as rough handling can cause cardiac arrhythmia;
• do not rub the limbs or give alcohol;
• insulate from the cold and from the wind (including from below), and add chemical heat packs to the chest, armpits and groin, not the limbs;
• give warm, sweet drinks only to a fully conscious casualty;
• a casualty who has stopped breathing may be revived even after a long time in cold water, so continue CPR until rescued.

Responsibilities of the On-Scene Coordinator in Detail

Whoever acts as OSC should do the following, in this order:

1. Establish communications with the MRCC and agree a working channel. Check that the working channel is clear.
2. Confirm the datum and the search area with the MRCC and plot them.
3. Assess the weather and sea state and report them in the first SITREP.
4. Identify the units arriving on scene and give each a task, a pattern and an area, and a height or distance for aircraft. Give each a call sign and a reporting interval.
5. Maintain separation. Search vessels in the same area must not collide. Tell vessels and aircraft their altitudes and track spacings. Vessels should keep a lookout for aircraft, and aircraft for vessels.
6. Keep a plot and a log. Record the search tracks, sightings, units' arrival and departure times, and the position of any wreckage and survivors.
7. Send SITREPs at the intervals agreed.
8. Recover survivors and brief the MRCC on their numbers and condition.
9. Hand over to a relieving OSC with a clear summary, and stay if needed.
10. Report when the search is called off and release units only when the MRCC authorises.

Example of a SITREP

"MRCC FALMOUTH, THIS IS YACHT TERN, OSC, SITREP ONE. TIME 1604. POSITION 50 04 NORTH 003 38 WEST. Situation: arrived at datum at 1555, no sighting yet. Weather: wind south-west 5 to 6, sea moderate, visibility 6 miles. Search: expanding square, track spacing 1 mile, starting at datum. Units on scene: yacht Tern only. Intentions: continue the pattern, ETA of lifeboat requested. Assistance needed: lifeboat and helicopter. OVER."

Exam Tips

• Say it in order: acknowledge, assess, proceed if safe, coordinate. Give the log as the last step.
• Know where the IAMSAR Manual Volume III is and what it contains (search patterns, SITREP formats, search techniques, survival craft guidance).
• Be ready to calculate a datum quickly from the chart with a tidal stream atlas and a leeway factor, and to describe in words an expanding square of a stated spacing.
• Be able to draw a sector search and an expanding square on paper, showing courses and turns.
• Explain why you tell the coastguard before you start searching.
• Show that you know your limits: a skipper who says "I would mark the position, report, keep the casualty in sight and wait for the lifeboat" in a gale is giving a correct answer.

Common Mistakes

• Searching at the LKP rather than the drifted datum.
• Not telling the MRCC what you are doing, or searching independently.
• Unnecessary DSC relays of a distress alert that has already been acknowledged.
• Inaccurate leg timing in expanding square searches, which leaves gaps.
• Too few lookouts, or lookouts with no allocated sector.
• Approaching a survivor from leeward under power so the yacht drifts away, or with the propeller turning close to people in the water.
• Lifting a hypothermic casualty vertically or rewarming too aggressively.
• Securing a helicopter winch wire to the boat, or touching it before it has earthed.
• Not logging times, positions and actions.

Summary

• There is a legal duty to assist people in distress, if you can do so without serious danger to your own vessel.
• MRCCs coordinate SAR; an SMC directs the mission and an OSC coordinates on scene. IAMSAR Volume III is the reference for vessels.
• Distress alerts arrive by DSC, EPIRB via Cospas-Sarsat, and voice. Mayday has absolute priority.
• Datum = LKP plus current drift plus leeway; recalculate it with time.
• Expanding square and sector searches for accurate datums, parallel sweep for large areas with several units.
• Keep the MRCC informed with SITREPs.
• Recover survivors into your lee, lift horizontally where possible and treat for hypothermia.
• Follow helicopter instructions: clear the deck, steady course, never secure the wire.

Check Your Understanding

1. What legal obligation does a yacht skipper have on receiving a distress alert?

Answer: Under SOLAS V/33 (applied to UK pleasure craft through the Merchant Shipping regulations), to proceed with all speed to assist if able to do so without serious danger to their own vessel and crew, and to log the reason if they do not go.

2. What is the difference between the SMC and the OSC?

Answer: The SMC is the person at the MRCC in overall charge of a SAR incident. The OSC is a unit at the scene designated to coordinate the search units present.

3. You receive a DSC distress alert. Should you relay it by DSC straight away? Explain.

Answer: No. Listen on Channel 16 and wait for a coast station to acknowledge. Only relay by DSC if instructed by the coastguard, or if you know the casualty is in distress and no coast station has acknowledged. Unnecessary relays cause confusion.

4. What is a datum and what affects its calculation?

Answer: The most probable position of the target at a given time. It is the LKP adjusted for total water current and the target's leeway multiplied by the time elapsed.

5. A person went overboard 2 hours ago. The tidal stream sets 180°T at 1.2 kn, and leeway is negligible. Where is the datum?

Answer: About 2.4 miles (1.2 x 2) towards 180°T from the last known position.

6. Describe the leg lengths of an expanding square search with track spacing S.

Answer: S, S, 2S, 2S, 3S, 3S, 4S, 4S and so on, with 90° turns in the same direction at the end of each leg, starting at the datum.

7. When would you use a sector search rather than a parallel sweep?

Answer: When the datum is accurately known and the area small, such as a man overboard seen to go in. Parallel sweep is for large areas with an uncertain position, usually with several vessels.

8. Why should a hypothermic survivor be lifted horizontally?

Answer: To reduce the risk of post-rescue collapse. When lifted vertically, blood pools in the legs and the heart, already stressed by cold, may fail.

9. What information goes in a SITREP to the MRCC?

Answer: Identity and position of the reporting unit, the situation, weather on scene, search pattern and area covered, units on scene, results, future intentions and assistance needed.

10. What two safety rules apply to a helicopter winch wire?

Answer: Let it touch the water or deck to discharge static before handling it, and never secure it to the boat.

11. A liferaft without a drogue was last seen at 1000. At 1200, the wind is 20 knots from the west and the stream sets south at 1 knot. Estimate the datum.

Answer: Leeway at about 5 per cent of 20 knots is 1 knot towards east. In 2 hours: stream 2 miles south, leeway 2 miles east. The datum is about 2.8 miles from the LKP on a bearing of 135 degrees True (the vector sum of 2 miles south and 2 miles east).

12. Give the format of a Mayday message in order.

Answer: MAYDAY three times; THIS IS and the vessel name three times with call sign or MMSI; MAYDAY and the name once; position; nature of distress; assistance required; number of persons on board; any other useful information; OVER.