Abandoned in a liferaft: SART on, no radar echo
At 02:15 local time, the 14 m charter yacht Nettuno (six persons) strikes a submerged object about 11 nm south of Isola d’Elba and begins taking water. The crew abandon ship into a liferaft in position 42°41.2′N 010°21.5′E. Wind is north-west 18 kn, sea state 3, visibility moderate. The yacht’s 406 MHz EPIRB was mounted inside the wheelhouse and went down with the vessel; it was not float-free. One crew member carried a handheld VHF (5 W, no DSC, battery at about 40%), a handheld GPS, and the yacht’s 9 GHz SART into the raft. The SART is switched on and lashed about 0.5 m above the raft floor, partly under the canopy. No search vessel or aircraft is visible. The crew can see a distant white light but cannot identify it. They must decide what to do first, how to use the SART, and how to manage the VHF battery.
1. What should the crew do first, given that the EPIRB went down with the yacht?
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The first priority is to make the distress known by the means still available. Because the 406 MHz EPIRB is at the bottom with the yacht, no satellite distress alert should be assumed. The crew should switch on the handheld VHF, select channel 16, and transmit a MAYDAY with the liferaft position from the handheld GPS, the number of persons, the nature of the casualty, the fact that the yacht has sunk, and the fact that a SART is switched on. They should repeat the MAYDAY at reasonable intervals and listen between calls. The SART is a locating aid, not an alerting device: it does not tell the rescue services that anyone is in distress unless a radar is interrogating it. The crew should also look for the distant white light, use torches or flares only when there is a realistic chance of being seen, and keep the raft closed as far as possible against wind and spray. Battery conservation starts immediately.
2. Why is the SART not producing an echo on the search radar, and what should be done with it?
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A SART responds only when it is interrogated by a 9 GHz radar. If no search radar is within range, or if the radar is not sweeping the raft, there will be no echo on the rescuer’s display. The SART’s mounting is also poor: it is only about 0.5 m above the raft floor and partly under the canopy, which reduces its effective height and may block the microwave path. It should be raised to at least 1 m above sea level, as high and as unobstructed as the raft allows, with the antenna clear of the canopy and metal parts. It should remain switched on, but the crew should not repeatedly test it unless a radar-equipped vessel is known to be close. A SART echo appears as a line of dots on the rescuer’s radar, not on the raft’s own equipment; the crew cannot expect to see an echo themselves. The correct action is to improve height and visibility and keep it on.
3. How should the crew manage the handheld VHF battery and communications while waiting?
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The battery is at about 40%, so the crew should use the VHF in a disciplined way. The initial MAYDAY on channel 16 should be sent immediately and repeated until acknowledged, but after that the set should not be left transmitting continuously. The crew should keep a listening watch on channel 16, make short scheduled calls at agreed intervals, and switch the set off between calls if nothing is heard. If a station answers, they should pass the position, number of persons, colour of the raft, SART status and any injuries, then follow instructions and switch to a working channel only if directed. The handheld GPS should be kept warm and dry, and the position should be written down in case the display fails. The SART should stay on. The crew should conserve flares for a confirmed target, use the raft’s torch sparingly, and keep a visual lookout. Battery management must not become an excuse for failing to make the distress call.