Diving brings many joys but it also comes with a few risk factors, equipment which we can mitigate by adopting safety protocols and mind- sets. In this extended feature, we take a closer look at measures that can be taken to avoid being lost at sea.

Getting lost at sea is a basic fear most outright terrifying experience. Even on divers can relate to. There is a whole a shore dive, you can get swept up by genre of movies about being lost at sea a , which is too strong to fight, in some shape or form, including the and end up being swept along, unable really bad film, Open Water—the 2003 to make it back on your own. So, now drama loosely based on the much-pub- what do you do? Has somebody been licised case of the American couple, keeping an eye on you from the beach Tom and Eileen Lonergan, whom most (or boat) who can provide some assis- divers active around the turn of the cen- tance, or raise the alarm? Did you bring tury have heard of. The couple disap- a SMB (a.k.a. safety sausage), which peared off the Great Barrier after you can deploy? their accidentally left them behind in open water, because the And in particular, if you are diving at crew failed to take an accurate head- night in hazy or foggy weather where count. It was not until two days later there are currents or , or in remote that the pair was discovered to be miss- areas, what means of communicating ing, after a bag containing their belong- with your dive boat and relaying your ings was found on board the dive position are you equipped with in case boat. The skipper of the dive boat was you get lost or cannot make it back on charged with unlawful killing but later your own? found not guilty. However, the operator was fined after pleading guilty to negli- Thanks to the ingenuity of various entre- gence and went out of business. preneurs, a range of affordable and small personal electronic devices have There can be no doubt that the opera- been on the market for some years, and tor neglected its , with trag- still more refined models are being devel- ic consequences. oped. Some are simply VHF radios or satellite phones in a waterproof housing While the Lonergan case prompted depth-rated for diving. More dedicated authorities, in Australia and elsewhere, devices comprise AIS or DCS transmitters, to introduce much tighter regulations, which send a message or distress alert to including the requirement that both vessels within range. But these units have the captain and another crew mem- no voice transmission or personal loca- ber must independently confirm each tor beacon (PLB) that alerts search and headcount. But no system is infallible, rescue services by transmitting a coded and even the most diligent human is message via the COSPAS-SARSAT global prone to making a mistake. The respon- satellite system to the nearest rescue co- sibility for our own safety always rests ordination centre. with ourselves, and we should never assume that others will step to cover our The use of some systems require a radio shortcomings in that regard. We should license, some do not. Some systems are always be safety-conscientious and free, while others require an annual sub- take reasonable measures to prevent scription to private companies. Some ending up in a precarious situation. systems are only legal in some parts of the world, or have varying local restric- Being at the mercy of a strong current, tions imposed, limiting their functionality. which may pick up with little or no prior notice under water or on the surface, Confused? You are not alone. can be a quite discomforting, if not an

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Text by Christiane Linkenbach Translated by Peter Symes As a diver, how does one rescue oneself when in dis- tress? Call rescue services? How do the different emer- gency frequencies work? Which one is the most effi- cient for divers?

Diver in distress? Yes, divers get into sticky situations too, and more frequently than one might think or read in the media. In particular, it happens whenever divers surface too far away from the dive boat, because they got caught in a current. Adrift alone, or with a buddy, divers find them- selves in the same life-threatening predicament as sailors falling over- board from a boat that just keeps sailing away. It has been the sailing industry that has long since looked into Emergency Transmitters for Divers safety measures and devices and — What You Know Could Save Your Life come up with what is known as

“MOB transmitters” (MOB: man- CHRISTIANE LINKENBACH over-board), some of which are also now being made as depth- Old wine in new bottles? years. It is just that divers are not trip. He sees all these seductive ous known certification markings But because he had this gadget, rated models for divers. These transmitters provide divers usually given any training or much presentations of paradisiacal such as CE, FCC and EMV, along he was soon safely back on the with some degree of peace of insight into sea rescue procedures resorts and alluring waters when with some other more or less famil- boat—and Joe should always DISCLOSURE: Christiane Linkenbach mind, because what is good and the use of marine radios. he suddenly finds himself in front iar symbols, which is comforting. wear one too. Joe is not quite sure is the deputy director of Seareq, for sailors must also be useful for A maritime radio licence is not of a poster depicting a diver lost It looks trustworthy. It is handy, what to make of the technical who manufactures the Enos person- divers, and one need not be con- required to go diving. But igno- at sea. The advert cleverly targets small, well-built and capable. The specifications but feels reassured al safety devices. This background article endorses no specific brand of cerned with obtaining a licence rance can kill here too. a latent fear, and Joe is drawn to sales representative comes up to that it would be good insurance equipment or product. There exists and undergo a lot of training to Imagine an average diver, Joe, take a closer look at the adver- Joe, all smiles, and relates how he against being lost at sea, and his no financial arrangements between operate them. After all, these who visits some dive expo look- tised rescue system. once resurfaced far from the boat worries are put to rest. the magazine and Seareq. devices have been in use for ing for inspiration for his next dive The gadget is labelled with vari- himself and understood the fear. This is, of course, a made-up

50 X-RAY MAG : 90 : 2019 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO equipment Transmitters

Dangerous presumption of what triggers an emergency Sea—a change in course may Every vessel? Not quite. Let us response, they rarely consider represent a rather low risk for the have a closer look at what really the position of the rescuer who ship. However, it still takes con- happens when a personal device may have to provide assistance. siderable time before a freighter is activated and how a captain First of all, the captain of a large can turn about and make it to of a commercial vessel, which ship—perhaps up to several hun- the drifting diver, because it must may be transiting beyond the dred metres long—is primarily be slowed down early in order horizon, in all likelihood, would responsible for the safety of his not to overshoot . You react. Is it safe to assume that or her crew and any passengers never hear of such spectacular such a vessel would receive the aboard, the vessel and its cargo, manoeuvres because they do not distress call and turn around? as well as his or her own life. Is it occur in reality. Are they obliged to respond to reasonable to assume that such a any MOB alarm raised by leisure captain can just stop, turn around Fuel versus rescue crafts, sailors, wind- or kite-surfers and provide assistance? Often, the captain is unable to and divers? The notion that “they No, it is not. Considering the turn around even if he or she are obliged to come to your momentum of a heavy ship trav- wanted to. In many cases, ships rescue” may suggest this is the elling at speed, it is quite unlikely are only carrying a precisely cal- case, underpinned by the fact the captain is able to assist most culated amount of fuel, which that coming to the rescue at sea leisure water-sportsmen in dis- does not allow for such a turn- is mandatory. Under international tress. With a stopping distance of ing manoeuvre. Without required maritime law, a skipper is obliged several nautical miles, it takes a reserves, it could leave the ship to provide immediate assistance good long while before a big ves- short of fuel to reach the next

PIXABAY within his or her means when he sel—say, a passenger liner, cargo port. Shipping has become highly or she becomes aware of an ship or tanker—comes to a halt. competitive, and time constraints stereotypical scenario but one he too has experienced surfac- as the sales rep keeps emphasis- emergency. This obligation is also Around busy or constricted ship- are tight. In order to carry as that often plays out in some ing far from the boat. “Been ing, it is fair to presume Joe would stipulated in the International ping lanes, it may also be impossi- many containers as possible, the shape or form—depending on there, done that!” he says and be oblivious that his intended use Convention on Maritime Search ble for a big vessel to alter course amount of fuel carried is precisely the product, its operating prin- proceeds to describe his product of the device may not always be and Rescue. due to risk of collision with other calculated and will only include ciple and distress frequencies in more technical terms. Some of legal. That is too absurd to con- traffic. That is also why most other a small “storm reserve.” These used, and of course, the compe- the lingo Joe has heard before, template. Who cares about for- But what does “within his ships cannot easily stop either. calculations are so finely tuned tence of the seller as well as the but he does not quite understand malities when lives can be saved? or her means” imply? If the emergency takes place in that they even consider the dif- previous knowledge of the diver. how this gadget is the to Who would not rather commit an While sales reps and custom- less-frequented waters—say, south ferent water densities of the vari- Being unfamiliar with some topic the problem. Joe does not want offence than die? ers may have their discussions of Brothers Islands in the Red ous seas. The Mediterranean and is something we can all relate to, to come across as ignorant, so he Saving lives and responding to so what do most of us do? We does not raise many questions. In distress always takes precedence seek advice, which is all good, between being lost in the techni- over adherence to formalities and provided the guidance is trustwor- cal jargon and mentions of AIS, procedures, the sales rep reas- thy, accurate and relevant—and DSC 70, EPIRB, Channel 16, PLB sures Joe, who ends up making when it helps us to make the right and 406 MHz, he also hears two a purchase. He leaves the booth decision and purchases that suit reassuring sentences: “Everybody feeling good and resumes looking our needs. But how do we make welcomes you here” and “They at travel destinations, convinced heads or tails out of sometimes must save you.” that he now has a transmitter that conflicting information and rec- will alert every vessel within X nau- ommendations? And how do we Cost tical miles about his predicament, see though the sales and market- Next up is the question of price. in case he ever ends up in distress ing babble? What does such a device cost? and needs to be rescued. Typically, prices are in the 150 to “They have to save you!” 400 USD/EUR/GBP range, which Are commercial shipping So, the smooth-talking sales rep stings a little, but not a big price vessels obliged to respond has managed to build a rapport for a potential life-saver. And to any MOB alarm raised by with Joe by relating to him that since sailors also use this device, leisure crafts, sailors, wind or kite-surfers and divers? CHRISTIANE LINKENBACH

51 X-RAY MAG : 90 : 2019 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO PIXABAY If average diver Joe ever finds himself adrift at sea and calls a passing ship on Channel 16, without following protocol, he may find equipment that the ship just continues on its course. Transmitters

Depending on the incident, a distinc- placing maritime radio emergency calls tion is made between an emergency can be kept on or beside the radio. report, an emergency message or a These aids also allow crew members safety message. Even calling off a (false) without SRC to call for help. Having a alarm must be made following a specific radio licence does not matter. Placing protocol. the call correctly does, and just yelling “Mayday, Mayday, Mayday” into the Just calling “Mayday, Mayday, ether will not help. Mayday” is not enough So, if Joe ever finds himself adrift at sea Protocols dictate how an emergency is and calls a passing ship on Channel 16, declared, how the caller presents him without following protocol, he may find or herself and how the emergency is that the ship just continues on its course. described. The call must include the The captain will likely consider him yet another prankster who clogs Channel 16 the are particularly popular with SAR in Sharm el-Sheikh, which immediately worldwide, and as a result, the nearest shipping companies, because the higher went to the designated location and res- MRCC will not be notified. That a diver salt content provides more , cued the diver. Thanks to the SAR station could be lost at sea for real is probably allowing for more cargo. being relatively nearby, the rescue could the last thing on the captain’s mind, and If a cargo ship south of Brothers Islands be carried out in a targeted manner. The receives the distress call from a drifting diver was in many ways unbelievably diver, the captain may well be left with lucky: Not only was he spotted by chance no choice but to carry on, as any action but survived the ordeal unscathed, after could deplete designated fuel reserves. drifting across the busy shipping route Accordingly, it would thus not be “within between Sinai and at the means” of the captain to provide night without being hit by any of the direct assistance. many passing vessels. Rather, the captain would notify the nearest Maritime Rescue Coordination Channel 16 and proper protocol Emergency calls over Channel 16 only have to be responded to when the emergency Centre (MRCC) of the emergency—in this Often, captains are merely unable to call is issued in accordance with the prescribed protocol form—in other words, when the case, the MRCC in Jeddah. The centre assist in a rescue. But at other times, they emergency caller knows and uses proper “radio language.” in Jeddah would most likely forward the are not obliged to—for example, when alert to the Egyptian MRCC in Alexandria, an emergency call is not placed accord- tocol can be dire, because emergency name of the ship and its radio PIXABAY which will coordinate the mission. Next, ing to protocol. It may sound unbeliev- calls on Channel 16 only have to be call sign—ideally, also the MMSI Alexandria would alert the Egyptian SAR able, but it is so and for a good reason: reacted to if the caller is unequivocally (Maritime Mobile Safety Identity), (Search and Rescue) in or El More than 90 percent of distress calls on recognised as an “authorised user.” This which is an individual ship identifi- Quseir from where a boat would be dis- various maritime radio frequencies are happens automatically when the emer- cation number comparable to the patched. It sounds complicated, but it is false alarms. It puts captains and rescue gency call is issued in accordance with chassis number of a motor vehicle. the quickest way, because Jeddah is a services in a dilemma when leisure craft the prescribed protocol form—in other As complicated as such strict pro- lot farther from the scene of the accident skippers are simply testing emergency words, when the emergency caller knows tocols may appear at first, they than the two Egyptian cities (whose ports calls to see if they work. Others are simply and uses proper “radio language.” are actually very effective, as they are too small for the largest vessels to misusing Channel 16, which is the marine Although communication is conducted ensure life-saving information such approach). In any case, it goes to show VHF channel designated as an inter- in English, command of the language as the type of vessel, number of how many unknown factors and how national distress frequency (156.8 MHz). is not enough. In order to effectively souls aboard, GPS (global position- many elements are involved in a rescue Primarily intended for distress, urgency broadcast on Channel 16, one is required ing system) position and nature of operation. and safety priority calls, this frequency to have at least an SRC (Short Range the emergency is expediently and In 2003, a Danish diver who aborted a may also carry routine calls to estab- Certificate)—a licence for leisure crafts clearly relayed to the parties in dive on the Thistlegorm wreck was acci- lish communication before switching to and water sports. Professionals must have charge of rescue. dentally spotted some 20 nautical miles another working channel, blocking the an LRC (Long Range Certificate). During To ensure that emergency calls away by the crew of a freighter, after channel and preventing real emergency the course, the correct procedures and are correctly placed even under being adrift for 20 hours. Instead of stop- calls in the process. emergency call protocol regarding or shock, stickers and cards Stickers and cards listing the procedures for cor- ping and turning, the captain radioed the The consequences of not following pro- Channel 16 are taught. listing these procedures for correctly rectly placing maritime radio emergency calls can be purchased for a few bucks, euros or quid.

52 X-RAY MAG : 90 : 2019 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO The technological options, pros and cons can be confusing. Be pre- pared and get the right equipment from the outset—get to know its uses and limitations. Once you find yourself in a precarious situation, it is too late to read the manial and figure out how it all works. Transmitters

quency spectrum. The first ship to receive argue that modern hi-tech needs to be range. In this mode, the emergency call a distress call on its DSC 70 receiver must made readily available to the increasing is only received by DSC 70 receivers on acknowledge the alarm and is required number of people on the water in order vessels whose MMSI numbers have been to coordinate the rescue. Once the to comply with SOLAS, the International previously stored in the transmitter. This alarm is acknowledged, it will be deac- Convention for the Safety of Life at Sea— does away with the principle of a big tivated to clear the DSC 70 channel for an international maritime treaty which alarm being broadcast to everybody any other emergency calls. sets minimum safety standards. within range, because past experience Despite DSC 70 being strictly regu- This makes for a delicate balancing has shown that it is not necessarily safer lated as well as the requirement of an act for decision-makers. On one hand, when all surrounding vessels hear of the SRC being in place, problems with false every human should be rescued as soon emergency. alarms are also on the rise in this area. as possible! On the other hand, the use Moreover, DSC 70 transmitters may also When purchasing a personal transmitter, of emergency frequencies must be inter- be used in closed loop mode by users it is therefore important to ascertain that nationally regulated so rescue can be who do not hold a marine radio license. the built-in DSC 70 button can only be carried out promptly. In any case, it is This could, however, change on short used once an MMSI has been associated of paramount importance that misuse notice, as such devices will automati- with the transmitter and that distress calls and incompetence is reduced, as each cally switch to the open loop mode after made over DSC 70 can be deactivated emergency call blocks the rescuers from seven to ten minutes if the alarm is not by other vessels. This feature indicates other operations. confirmed by one of the programmed whether the personal rescue system is receivers, after which the call goes out to legal or not. Also, some transmitters are Closed loop or open loop all vessels within range as before. unable to receive confirmations, or be Among the latest technology now avail- For this arrangement to work, it is shut off remotely, once alarms have able are MOB transmitters using a so- assumed the dive vessel is equipped with been received. called “closed loop mode,” which makes a corresponding DSC receiver. However, Devices that do not meet the require- it possible to call for assistance without as it is not mandatory for all vessels to carry ments may put the whole system at risk raising the alarm with every vessel within receivers with channel DSC 70, it should and jeopardise everybody’s safety at sea. Already in 2013, FSR—a German trade association for res- cue equipment— warned that “the effectiveness of Joe would only have himself to blame for ters equipped with channel DSC 70 have the entire system being left at sea. only been on the market for a few years. of mutual assis- It is important to note that if MMSI is not tance at sea is in DSC 70 entered into the transmitter, the capabil- danger” due to Some distress rescue stations for divers ity to place DSC 70 emergency calls is improper use of are also equipped with digital selective deactivated and cannot be used. This handheld radio calling or DSC, which was developed to feature is there to prevent the wide- devices with a dis- replace a voice call in older procedures. spread abuse associated with Channel tress button. DSC senders are programmed with the 16. Since an emergency call transmit- While some ship’s MMSI and may be connected to ted on DSC 70 has a range of up to 60 argue paragraphs the ship’s GPS, which allows the appara- nautical miles, any misuse or false alarms and applicable tus to know what ship it is, what time it is would be heard by quite a few. laws are required and where it is. This allows a distress signal to restrict access to be sent very quickly. Until a few years The international treaty to maritime res- ago, this channel was only installed in Responding to emergency calls over DSC cue frequencies radios that were permanently installed in 70 is obligatory, as per the international in order to pre- the wheelhouse. Personal MOB transmit- treaty governing the use of the radio-fre- vent abuse, others

PIXABAY

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for commercial shipping, the AIS cial shipping and leisure craft, which cost over 2,000 Euros, in industry requested the IMO to two classes of transmitters were order to increase their chances of also authorise the frequency for defined: “SART Class A” and being spotted. personal maritime rescuers, so “SART Class B” (SART: Search And the improved safety in seafaring Rescue Transponder). AIS MOB Transmitter Class A could find its way into personal SART A transmitters for commer- Personal AIS channels are cate- rescue. AIS MOB transmitters hit cial shipping send data in inter- gorised under class A, so they are the market in 2010 and caused vals between 30 seconds and six given high priority since they are some hype among sailors. The minutes. In order for each signal (in theory) only activated in the royalty-free AIS frequency does to be seen by the other subscrib- case of an emergency. However, not require an SRC, so sailors were ers in the AIS system, the devices since they are just battery-pow- able to equip their life jackets reserve time slots in the system. ered, they have the weakest with an AIS transmitter. As the sta- Meanwhile, SART B transmitters power of all AIS broadcasters— tions sold very well, the AIS indus- used by recreational sailing must just one watt. Thus, the signal try was obviously quite pleased. wait until a free time slot is avail- would stand little chance of get- Much less happy were search- able for the transmission of the ting through in regions where all and-rescue teams, coast guards radio signal, which works reliably time slots are occupied. and commercial shipping, which if enough time slots are available. Another restriction is that plot- soon experienced a firework of But in regions with heavy traf- ters built before 2010 do not rec- alarms on their plotters. Although fic such as the English Channel, ognise the MOB icon in the AIS CHRISTIANE LINKENBACH each AIS-MOB transmitter has a the SART B signals of recreational system (an X in a circle). On these never be presumed they have one mitters, which require special on- so, it relies on the International “test button” to simulate and train boating may not get through and older screens, the received signal installed. For example, many dive board receivers to receive the Maritime Organization’s (IMO’s) emergencies, most of the MOB will not appear on the plotters would display as a triangular icon, centres work with different day AIS signals. Originally, the AIS was regulation that every commercial training was unfortunately done of the surrounding ships. This has which is the symbol for a ship, boats, which are hired locally, such developed as an “anti-collision vessel must have AIS on board. In with the “sharp” alarm button. In prompted some entrepreneurs which may obfuscate the true as dhonis, Philippine outriggers, or system” for commercial shipping. reality, that is not the case in every areas with heavy traffic such as to develop some special class A nature of the emergency. inflatable boats—none of which Using the AIS frequency, vessels region of the world, because the the bay of Kiel in the southwestern transponders for pleasure craft, have an MMSI. exchange information on their IMO allows its member states so- Baltic Sea—which is In order to fully appreciate the position, ship’s name, , called “national exemptions,” of rife with ports, mari- GPS-Satellite advantages and limitations of load, speed and so on. Since which some popular dive des- nas, wharfs, a naval using DSC 70, it is therefore neces- 2000, the system has been man- tinations such as and the base, busy ferry cross- sary for our average diver Joe to datory for commercial shipping Maldives make use. ings and lots of leisure gain a deeper understanding of worldwide. In the Maldives, cargo ships boats—the plotters how the technology works and its In order to receive information approach the port of Malé in a became swamped. limitations. Only, few divers do. from other vessels, an AIS receiver large arc and not through the Our friend Joe has done his is required. This is connected to a atolls, and there are no terrestrial Transmitter homework, and on his next dive plotter (screen) on which a digital AIS antennas there. As a result, Classes A and B trip, he arrives on location with his nautical chart is displayed. On this the Maldives government does To differentiate stationary newly purchased transmitter with chart, every vessel is displayed in not require AIS equipment aboard between commer- terrestrial a DSC 70 button for closed loop relation to other ships and con- dive boats and dhonis. In Egypt, AIS-Antenna function. Once aboard the dive stantly updated. Thanks to station- the government is protecting the boat, he asks the crew about ary terrestrial antennas, it is even fishermen, who operate as micro- The AIS was origi- their MMSI, and to his chagrin, possible to detect ships when entrepreneurs but cannot afford nally developed as finds that nobody has any idea they are still behind headlands or AIS. Therefore, in Egyptian territorial an “anti-collision about it—or worse, that there is cliffs and not yet visible. Since the waters, AIS is allowed but not com- system” for com- no DSC 70 receiver on board. implementation of this system, the pulsory. Consequently, many dive mercial shipping but was later adopted number of collisions at sea has vessels there are not equipped for personal transmit- AIS fallen sharply worldwide. with an AIS system either. ters too. Use of AIS Such scenarios apply equally to The AIS industry is happy to sug- transmitters does Automatic Identification System gest that AIS receivers are now AIS as an MOB alarm not require a radio (AIS) frequency emergency trans- installed on every ship. In doing Since AIS became compulsory licence. COURTESY OF CHRISTIANE LINKENBACH

54 X-RAY MAG : 90 : 2019 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO Dive instructors should possess equipment knowledge of how present-day sea Transmitters rescue works, how it is structured, and which safeguards have been implemented to keep thoughtless individuals from messing about with this crucial system.

Waves absorb radio signals Such complications do not personal units handheld by a drift- Many AIS handheld units also exactly make it any easier for our ing sailor or diver—except where require an antenna to be unfold- average diver Joe to make heads explicitly specified. ed, or unrolled, prior to use. As a or tails of the technical informa- result, they may not be deployed tion. One brochure may, for exam- Factors influencing trans- vertically but in some other posi- ple, state that the transmitter has mission quality and range tion, which is not optimal for trans- a range of 55km—which, in a strict Water absorbs all radio frequen- mission. It is already a significant sense, may be true. However, this cies used for emergency signals, challenge that water absorbs may only apply when the transmit- so waves of any significant height radio signals, and sea waves block ter is mounted high up on top of a will block most of the transmission. the transmission. One must there- wheelhouse of a big ship and con- On top of this, AIS alarms will be PIXABAY fore also understand the physical nected to a tall antenna. It should further attenuated if the antenna circumstances at play and how therefore never be presumed is not held vertically but at a slant. only up to one watt maximum for complex manner, that it is impos- cal tensions following the Cold they may affect the transmission of that the stated range and other The biggest limitation, however, battery-powered handhelds. sible to put it in a simple formula. War. At the time, nobody envis- an emergency signal. performance data also apply to is the low transmission power of Even in areas with low traffic, Any statements to the contrary aged how many different func- AIS-MOB transmitters cannot be are either unscrupulous or incom- tions it would eventually comprise. expected to reach their stated petent (or both), and can have The effort going into technologi- maximum transmission range of dire consequences for users who cal development today is small in up to eight nautical miles (15km). do not know otherwise. comparison to what it took to set In reality, most will only cover 1.2 It would thus be a welcome up the first international emergen- to 3 nautical miles (2 to 5.5km), change if dive training organisa- cy call frequency 406 MHz. which various reviews have dem- tions would provide some basic This frequency was initially avail- onstrated. knowledge of how sea rescue able only to ships, because the It is quite important how high up works, given the fact that distress emergency transmitters were the receiving antenna is mount- rescue stations are increasingly large beacons mounted on the ed—the higher it is, the better the pushing into the diving market. ship’s deck. These beacons are range! Dive boats rigged with sails It does not mean that divers or called EPIRBs (Emergency Position are able to mount their receiv- even instructors should necessarily Indicating Radio Beacons) and ers high up on the mast where it have an SRC. But they should at are triggered by water contact can pick up alarms from longer least possess knowledge of how such as when a ship is listing distances. But when it is mounted present-day sea rescue works, or sinking. Initially, these bea- on the roof of a small cutter, the how it is structured, and which cons were connected to GPS diver better not have been drift- safeguards have been imple- (which was permitted for civilian ing far, the sea better be smooth mented to keep thoughtless indi- use in the 1980s), but sent their and there should only be a few viduals from messing about with emergency calls with MMSI to ships around, for the AIS distress this crucial system. dedicated satellites, which were signal to go through. On a side launched into space for this very note, it should be added that the EPIRB purpose. From these satellites, the density of the atmosphere, the It was during the 1970s when the distress calls were forwarded to curvature of the earth and even United States, Canada, France one of the more than 40 receiving solar storms also affect the range and the Soviet Union came stations, called LUTs (Local User of a radio transmission wave. In together and jointly developed a Terminals), which are spread out any case, there are so many fac- global rescue system for commer- over the globe. The LUT then for- tors, which come together in a cial shipping, despite all the politi- wards the emergency call to the

PIXABAY

55 X-RAY MAG : 90 : 2019 EDITORIAL FEATURES TRAVEL NEWS WRECKS EQUIPMENT BOOKS SCIENCE & ECOLOGY TECH EDUCATION PROFILES PHOTO & VIDEO PORTFOLIO TESTING FOR LED INTERFERENCE

equipment LED lights may interfere with VHF radiotelephone, AIS and DSC devic- es. The US Coast Guard has issued a “Marine Safety Alert” regarding the potential interference of VHF- FM radio and AIS reception from LED lighting. It has quite recently been found that LED bulbs may emit interference in the same frequency nearest MRCC, of ​​which more than 40 sta- mounted on the wall and are no longer of the aforementioned radios. tions also exist worldwide. From here, what- installed on the deck. Personal emergency Although the jury is still out and there ever RCC (Rescue Coordination Station) transmitters, which were attached to life is no solid scientific results yet, skip- was closest to the scene of the accident jackets and clothing, were introduced. pers are urged to conduct a test to and where the SAR initiated the rescue They are called PLBs (Personal Locator find out if their on-board radios are was alerted. Beacons) and also work on the 406 MHz also compromised. This is a rather complex chain, but even frequency, on the same principle as the for ships that find themselves in distress alone EPIRB. For divers, there are depth-rated quick- Nonetheless, it may be possible on the high seas, this is the only system, even models in underwater housings, which first ly estab- for to test for the presence of LED today. As horizontal radio transmission is lim- have to be opened at the water’s surface lish whether the interference by using the following ited by the many aforementioned factors, in order to raise the alarm in the case of the alarm is real sake of making a profit. procedures: emergency calls must be routed via satel- an emergency. or false, two additional steps have been There are some real issues lites in order to reach over the horizon. In the For decades, 406 MHz was the only res- built into the rescue chain. First, each and limitations to consider as well 1. Turn off LED light(s). open ocean, the signal may have to travel cue frequency for ships, and MOB, the PLB is kept in a database, with the name as the occasional misleading information several thousand kilometres. only chance of rescue. Right from the of the owner and the contact details of or overreaching marketing pitches to weed 2. Tune the VHF radio to a quiet onset, this system was also plagued by another person who knows the owner out, which is not easy considering the channel (e.g. Ch. 13). PLB false alarms, both due to technical prob- (emergency contact). Second, in case of complexity of the matter. Over the years, the EPIRB has become lems and to improper handling. an emergency, this designated person will As divers, we just seek to safeguard our- 3. Adjust the VHF radio’s squelch smaller. Today, such transmitters can be In order not to block rescuers and to be contacted by the MCC to confirm that selves from being lost at sea. Fair enough. control until the radio outputs audio the sender is actually at sea. But in doing so, we still have the primary noise. This protocol should ensure that genu- responsibility for our own safety. First of ine emergencies are verified as such and all, that means taking every reasonable 4. Re-adjust the VHF radio’s squelch passed immediately on to the RCC and precaution to ensure we do not end up in control until the audio noise is SAR. It may appear a bit complicated, but such a predicament in the first place, and quiet, only slightly above the noise it only adds a few minutes to the response not relying on having a personal safety threshold. time, which is worth the while in order device to call in a ride home to safety. to prevent initiating unnecessary rescue It is basic, sound principle that we should 5. Turn on the LED light(s). If the operations in the case of false alarms. never rely on delegating any degree of radio now outputs audio noise, responsibility for our own safety to other then the LED lights have raised A blessing and a curse people—it is plainly wrong, and danger- the noise floor. (The noise floor is It is a blessing we now have technology ous. And this goes for the purchase and generally the amount of interfering that makes it possible to respond to and use of safety devices too. Any distress calls signals or static received beyond rescue people in distress even over long made will, to various degrees, either incon- the specific signal or channel being distances. Large thanks are owed in par- venience other people or put them at risk. monitored.) ticular to the sea rescue services and their We owe it them—and to our loved ones— members, many of which are volunteers, to make sure we understand the design, 6. If the radio does not output who often risk their own lives to help oth- technical features and proper use of these audio noise, then the LED lights ers. Their heroic attitudes cannot be com- devices, as well as the implications if we have not raised the noise floor. mended often enough. do not. Should we one day have to raise A salient point must therefore be made the alarm for real because we, despite our If the noise floor is found to have that personal safety at sea cannot be best efforts, end up in a perilous situation, been raised, then it is likely that viewed as just yet another product category we should be able to correctly use and both shipboard VHF marine radio of equipment, which can be purchased rely on a system that has been created to and AIS reception are being COURTESY OF CHRISTIANE LINKENBACH and some of which are produced primarily save our lives.  degraded by LED lighting. 

Rescue Operation, International Emergency Frequency / 406PIXABAY Mhz

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