Global Maritime Distress and Safety System GMDSS

1. 1 Global Maritime Distress and Safety System (GMDSS) Seminar prepared by Bruce E. Meyers

2. 2 Background: Rapid development of digital and satellite technology has made it possible to significantly improve the Safety Of Life At Sea (SOLAS). In 1979, the International Maritime Organization (IMO) decided a new global distress and safety system should be established using the latest technologies.

3. 3 GMDSS GMDSS is a tiered communications system using multiple technologies GMDSS includes sea, land, air, and space based hardware The equipment requirements increase as distance from land; and Search and Rescue (SAR) assistance increases

4. 4 GMDSS Sea Areas Sea Area A1 – an area within the radiotelephone coverage of at least one VHF coast station in which continuous DSC coverage is available Sea Area A2 – an area excluding A1, within the radio telephone coverage of at least one MF coast station in which continuous DSC coverage is available

5. 5 GMDSS Sea Areas Sea Area A3 – an area, excluding sea areas A1 and A2, within the coverage of an INMARSAT geostationary satellite in which continuous alerting is available Sea Area A4 – an area, excluding sea areas A1, A2, and A3, (polar regions above 75 deg. North latitude and below 75 deg. South latitude; and outside of INMARSAT coverage)

6. 6 GMDSS Defined Sea Areas

7. 7 Equipment Requirements Due to the range limitations of each communications system, the type of communications equipment required to be carried on a ship is determined by the sea area in which the vessel travels

8. 8 Equipment Requirements The GMDSS prescribed communications equipment and capabilities are mandated for most commercial vessels, defined as “Compulsory Vessels” The GMDSS prescribed equipment is not mandated for recreational vessels but is highly recommended due to the safety it provides. A non-compulsory vessel with GMDSS equipment installed is considered to be “Voluntary”

9. 9 Equipment Requirements Vessels classified as “Voluntary” may then have some of the GMDSS requirements imposed upon them by law. Examples include maintaining equipment certifications current; and watch-keeping and log-keeping. Failure to do so can result in enforcement actions. More on this subject later.

10. 10 Every “Compulsory” vessel engaged in voyages exclusively in Sea Area A1 shall be provided with the following radio equipment VHF Radio with DSC and watch-keeping on Channel 70 NAVTEX receiver Radio facility for reception of maritime safety information by IMARSAT enhanced group calling or HF direct print telegraphy if sailing in areas where NAVTEX is not available

11. 11 Every “Compulsory” vessel engaged in voyages exclusively in Sea Area A1 shall be provided with the following radio equipment Satellite EPIRB (COSPAS-SARSAT or INMARSAT) or VHF EPIRB Search and Rescue Transponder (SART) Portable VHF Radio VHF Channel 16 watch-keeping receiver (Requirement discontinued by GMDSS after 1 Feb 1999 but still imposed by FCC regulations on US vessels in US waters

12. 12 Every “Compulsory” vessel engaged in voyages in Sea Area A1 and A2 shall be provided with all the equipment required in Sea Area A1 plus the following radio equipment MF transceiver with DSC and watch-keeping on 2187.5 kHz

13. 13 Every “Compulsory” vessel engaged in voyages in Sea Area A1, A2, and A3 shall be provided with all the equipment required in Sea Area A1and A2 plus the following radio equipment (2 options possible) Option 1 – INMARSAT SES A, B, or C Option 2 – MF/HF radio transceiver with DSC and watch-keeping on 2187.5 kHz and 8414.5; and at least one of the frequencies 4207.5 kHz, 6312 kHz, 12577 kHz, or 16804.5 kHz

14. 14 Every “Compulsory” vessel engaged in voyages in Sea Area A1, A2, A3, and A4 shall be provided with all the equipment required in Sea Area A1, A2, and A3 Equipment Option 2 plus the following radio equipment COSPAS-SARSAT EPIRB

15. 15 Equipment Requirements Numbers of SARTs and portable VHF radios increase with vessel tonnage and vessel type, i.e. passenger GMDSS equipment must be capable of being powered from a reserve power source independent from the propulsion or main electrical system, (Normally ship’s house batteries or equipment’s internal batteries. A battery bank used to start engine is not independent from the propulsion system and does not satisfy this requirement. A genset is not independent from the main electrical system and does not satisfy this requirement)

16. 16 Equipment Requirements In 1996, the US government has ended the requirement to possess a Ship’s Station Radio License for VHF radios, including DSC equipped radios, Radar, and EPIRBs aboard recreational vessels used exclusively in US waters. If the vessel is greater than 65 feet in length, travels to foreign ports, communicates with foreign stations, communicates using SSB on MF or HF, or communicates by satellite, a Ships Station Radio License is required.

17. 17 Equipment Requirements The possession of a US issued Ship’s Radio License does not necessarily make it legal for you to use that equipment when in a foreign country. You may be required to obtain a reciprocal license from that country, this generally required payment of a fee; or they may entirely prohibit its use. A Ship’s Radio License does not cover the use of a Ham Radio, or Ham frequencies, which are licensed separately by the FCC in the US, and may necessitate a second reciprocal license when in a foreign country.

18. 18 Equipment Requirements A Marine SSB radio cannot normally access Ham radio frequencies. Access to Ham frequencies can be enabled if the owner possesses both a Ship’s Radio License and a Ham Radio License. A Ham radio cannot be legally altered to access Marine Band frequencies.

19. 19 Application for a Ship’s Station License Application for a Ship’s Radio License can be made on line at http://fcc.gov/formpage.html. Or call 1-877-480-3201 to obtain hardcopy forms. Application for a Ham License requires taking a test. Knowledge of Morse code is no longer required. A Ham Radio is not normally considered GMDSS equipment except as a possible provider of weather information in lieu of NAVTEX. Ham radio is a detailed subject on its own and is not included in this seminar.

20. 20 Application for MMSI via Ship’s Station License A MMSI, Mobile Marine Station Identification number (required for DSC) can be obtained concurrently via application for a Ship’s Radio License. Recommended If you clearly do not require a Ship’s Station License nor anticipate needing one anytime in the future, a MMSI may be obtained for West Marine or Boat US.

21. 21 Application for MMSI MMSI numbers obtained from West Marine or Boat US are not included on the SAR database available to international SAR authorities. Thus, the DSC and Distress Pushbutton function of your VHF or SSB radio may be rendered inoperable or impaired outside of US waters.

22. 22 Application for MMSI The MMSI numbers obtained from West Marine and Boat US are different from the MMSI numbers obtained from the FCC. A number obtained from West Marine or Boat US cannot be reused should you later apply for a Ship’s Radio License. A new MMSI will need to be assigned.

23. 23 Application for MMSI Most DSC radios allow only two opportunities to input MMSI or vessel information into the radio’s memory before having to return radio to factory to clear and reset the memory fields. This process is not error tolerant and factory service is expensive.

24. 24 Application for MMSI If there is any chance, even if remote, that you will sail your boat into foreign waters, I recommend obtaining your MMSI from the FCC.

25. 25 Got’cha The process of obtaining a Ship’s Station License or a MMSI require you to provide specific information. One bit of required information is a declaration of a “Radio Service.” Specifically, if your vessel is classified as “Compulsory” or “Voluntary” in accordance with the GMDSS requirements. In doing so, you may be accepting the GMDSS requirements as binding even though the GMDSS equipment is not normally required on a vessel of your size and usage.

26. 26 Got’cha In preparing this seminar, it became clear that regulations have not kept up with changing technology. It is unclear as to the extent GMDSS requirements become binding on “Voluntary” vessels. There has been no attempt to force installation of GMDSS equipment on non-compulsory recreational vessels, unless required by other criterion. However, “Voluntary” vessels have been cited for functionally inoperable GMDSS equipment, non-use of GMDSS equipment, failure to maintain equipment registrations or certifications, or failure to log GMDSS communications.

27. 27 Got’cha Examples are: Functionally inoperable GMDSS equipment – GPS not wired to radio and no MMSI associated with radio. This renders “Distress” function non-functional and inability to maintain Channel 70 watch. Non-use of GMDSS equipment – Radio off. No Channel 16 or Channel 70 watch and no distress function. Failure to maintain equipment registrations or certifications – battery certification expired or failure to register EPIRBs with authorities

28. 28 Got’cha Failure to log GMDSS communications – GMDSS communications are required to be logged. The regular ships log will satisfy this requirement. A “Mayday” call sent or responded to by your vessel is an example of a loggable GMDSS communication. A “Mayday” call initiated by another vessel is not a loggable communication unless you become involved in some manner.

29. 29 Installing Your VHF or SSB Radios Read the directions thoroughly. Have it professionally installed if you are not comfortable doing it yourself. Use only marine grade hardware. House or automotive wiring is not acceptable. Keep radios, speakers, and wiring as far away from your compass and navigation electronics as practicable.

30. 30 Installing Your VHF or SSB Radios Electro-Magnetic Interference (EMI) can be minimized by twisting power leads together and by the use of shielded signal leads. Your VHF and/or SSB must be connected to your GPS or other navigation equipment to obtain ship’s position. This is required for Channel 70 standby watch and the Distress Pushbutton to function correctly.

31. 31 Installing your VHF or SSB Radio After installation is complete, test all combinations of electronic components. For example, key radios and check for erratic operation of compass, auto helm, and other indicators; run engine, genset, and other equipment and check for static on radios.

32. 32 VHF Radio – ICOM 602 Most popular radio according to SSCA

33. 33 SSB Radio – ICOM 802 Most popular SSB radio per SSCA

34. 34 Emergency Position Indicating Radio Beacon - EPIRB

35. 35 COSPAS – SARSAT EPIRBs COSPAS Space System for Search of Distress Vessels (a Russian acronym) SARSAT Search and Rescue Satellite-Aided Tracking

36. 36 Emergency Position Indicating Radio Beacon - EPIRB Class A 121.5/243 mHz. Float-free, automatically-activating, detectable by aircraft and satellite. Coverage is limited. An alert from this device to a rescue coordination center may be delayed 4 - 6 or more hours. These devices have been phased out by the FCC and are no longer recognized. Class B 121.5/243 mHz. Manually activated version of Class A.  These devices have been phased out by the FCC and are no longer recognized. Class C VHF ch15/16. Manually activated, operates on maritime channels only. Not detectable by satellite. These devices have been phased out by the FCC and are no longer recognized. Class S 121.5/243 mHz. Similar to Class B, except it floats, or is an integral part of a survival craft.  These devices have been phased out by the FCC and are no longer recognized.

37. 37 Emergency Position Indicating Radio Beacon - EPIRB Category I 406/121.5 mHz. Float-free, automatically activated EPIRB. Detectable by satellite anywhere in the world. Recognized by GMDSS Category II 406/121.5 mHz. Similar to Category I, except is manually activated. Some models are also water activated. Recognized by GMDSS Inmarsat E 1646 mHz. Float-free, automatically activated EPIRB. Detectable by Inmarsat geostationary satellite. Recognized by GMDSS. Not sold in the U.S. International monitoring will cease 1 Feb 2009.

38. 38 Emergency Position Indicating Radio Beacon - EPIRB Category I and II are available with an internal GPS, interface with a ship-borne GPS, or non-GPS. An EPIRB with an internal GPS is the most expensive. When activated, it broadcasts current GPS coordinates. Recommended. An EPIRB that is interconnected with a ship-borne GPS will broadcast the last available coordinates. This GPS is dependent upon function of the ship’s GPS for information. Non-GPS EPIRB. The ship’s position is triangulated by SAR authorities using information from multiple satellites. Least expensive; and least accurate and least timely position information.

39. 39 Cat 2 (manual deploy) EPIRB mounted above Nav. Station

40. 40 Cat 1 (auto-deploy type) EPIRB mounted in “secured” location. EPIRB is not auto deployable from this location

41. 41 EPIRB Registration Proper registration of your 406 MHz satellite emergency position-indicating radio beacon (EPIRB) is intended to save your life, and is mandated by Federal Communications Commission regulations. The Coast Guard is enforcing this FCC registration rule. Your life may be saved as a result of registered emergency information. This information can be very helpful in confirming that a distress situation exists, and in arranging appropriate rescue efforts. Also, GOES, a geostationary National Oceanic & Atmospheric Administration weather satellite system can pick up and relay an EPIRB distress alert to the Coast Guard well before the international COSPAS-SARSAT satellite can provide location information. If the EPIRB is properly registered, the Coast Guard will be able to use the registration information to immediately begin action on the case. If the EPIRB is unregistered, a distress alert may take as much as two hours longer to reach the Coast Guard over the international satellite system. If an unregistered EPIRB transmission is abbreviated for any reason, the satellite will be unable to determine the EPIRB's location, and the Coast Guard will be unable to respond to the distress alert. Unregistered EPIRBs have needlessly cost the lives of several mariners since the satellite system became operational.

42. 42 What happens when your EPIRB is activated? The registration sheet you fill out and send in is entered into the U.S. 406 Beacon Registration Database maintained by NOAA/NESDIS. If your EPIRB is activated, your registration information will be sent automatically to the appropriate USCG SAR Rescue Coordination Center (RCC) for response. They will attempt to contact the owner/operator at the phone number listed in the database to determine if the vessel is underway (thus ruling out the possibility of a false alarm due to accidental activation or EPIRB malfunction), the intended route of the vessel if underway, the number of people on board, etc., from a family member. If there is no answer at this number, or no information, the other numbers listed in the database will be called to attempt to get the information described above needed to assist the RCC in responding appropriately to the EPIRB alert.

43. 43 What happens when your EPIRB is activated? When RCC personnel contact the emergency phone numbers you provide, they will have all the information you have provided on the registration form. You should let these contacts know as much about your intended voyage as possible (i.e., intended route, stops, area you normally sail/fish/recreate, duration of trip, number of people going, etc.).  The more information these contacts have, the better prepared our SAR personnel will be to react. The contacts can ask the RCC personnel contacting them to be kept informed of any developments, if they so desire.

44. 44 EPIRB Registration and your Float Plan Before departing the dock, file a Float Plan with at least 2 responsible individuals. These individuals should have multiple means of contact to ensure contact can successful Use the same contacts on your EPIRB registration so that SAR authorities contact the people that have your correct information Every crew member should know how to deploy your EPIRB, without further assistance, when directed to do so.

45. 45 NAVTEX The International Maritime Organization has designated NAVTEX as the primary means for transmitting coastal urgent marine safety information to ships worldwide. In the United States, NAVTEX is broadcast from Coast Guard facilities in Cape Cod, Chesapeake VA, Savannah GA, Miami FL, New Orleans LA, San Juan PR, Cambria CA, Pt. Reyes CA, Astoria OR, Kodiak AK, Honolulu HI, and Guam.

46. 46 Furuno NX300 Navtex Receiver (non-printing, can be connected to computer for print function)

47. 47 Navtex The Furuno NX300 Navtex Receiver shown on the prior slide does not satisfy the GMDSS requirements on a “Compulsory” vessel due to the lack of a print function. This Navtex receiver is one of the more popular receivers on “Voluntary” recreational vessels. To date, no one had made an issue of this.

48. 48 Search and Rescue Transponder SART One or more SARTs are required on “Compulsory” Vessels depending on vessel size and usage. A SART is a combination radar receiver and transmitter. When the receiver detects an “X” band radar transmission (UHF between 9.2 and 9.5 gHz) from a ship or aircraft, it will activate its internal transmitter and broadcast a series of 12 dots leading to the position of the SART with a gap of 0.6 nm.

49. 49 Search and Rescue Transponder SART These 12 dots are displayed on the rescue vessel’s radar screen. As the rescue vessel approaches the SART the 12 dots become a series of 12 arcs that increase in size as the vessel gets closer. As the rescue vessel reaches the SART or flies over the SART, the arcs become a series of concentric circles much like a “target.” When it receives a signal from an X-band radar, and transmits its own signal, it will either flash an indicating light and/or activate a buzzer to inform you that an approaching radar is activating the SART. This would be a good time to signal the SAR vessel using visual signals and/or use your handheld VHF to contact the approaching SAR vessel.

50. 50 Search and Rescue Transponder SART Since the radar UHF signals can only effectively travel in a straight line, the distance from which a SART can be activated by a radar is dependent on its own height and the height of the interrogating radar scanner. Most SARTs have an extendible handle to help in positioning it as high as possible in the life raft or lifeboat. The SART should be secured outside the canopy of the life raft. Operating it from inside the life raft will greatly reduce its effectiveness. The IMO design criterion requires that a SART mounted at a height of one meter must be detectable by a ship's radar with a scanner height of 15 meters at ,distance of at least 5 miles. Test results indicate that a ship's radar will usually detect a SART laying flat on the floor of a life raft at around 1.8 miles. If the SART is upright on the floor the detection range increases to about 2.5 miles. A normal detection range for a SART mounted two meters above sea level by an average ship's radar is about seven to ten miles. A search aircraft equipped with an X-band radar should be able to detect it from at least 30 miles when flying at an altitude of around 3,000 feet.

51. 51 Search and Rescue Transponder SART SARTs only broadcast your relative location to nearby rescue vessels already looking for you. They do not alert SAR Authorities of your emergency. They do provide an audible and visual notification when they are interrogated by a rescue vessel’s radar. This may help alleviate the panic you may experience when seated in a life raft at sea.

52. 52 Search and Rescue Transponder SART

53. 53 INMARSAT INMARSAT is a private company based in London, England offering private satellite communications to marine and aviation customers. INMARSAT has struggled to find a place in the market place. Only its satellite telephone service seems to have found a market. As shown in the following slide, INMARSAT does not currently have global coverage. In Feb. 2009, INMARSAT is expected to commission several new satellites in polar orbits and reposition others to acquire global coverage.

54. 54 INMARSAT

55. 55 INMARSAT Inmarsat-A: provided voice services, telex services, medium speed fax/data services and, optionally, high speed data services at 56 or 64 kbit/s. The service was withdrawn at the end of 2007. Inmarsat-B: provides voice services, telex services, medium speed fax/data services at 9.6 kbit/s and high speed data services at 56, 64 or 128 kbit/s. Inmarsat-C: This is a text message service. Certain models of Inmarsat-C terminals are also approved for usage in the GMDSS system, equipped with GPS. This equipment is expensive, (> $10,000) and bulky. It is clearly intended for commercial applications.

56. 56 INMARSAT Inmarsat-E: A global maritime distress alerting service using small Float Free Emergency Position Indicating Rescue Beacon (EPIRB) that automatically relayed distress messages to maritime Rescue Coordination Centers. This service has been withdrawn. Monitoring will be discontinued 1 Feb. 2009 Inmarsat-M: INMARSAT-M is the first generation satellite phone service. It provides voice services at 4.8 kbit/s and medium speed fax/data services at 2.4 kbit/s. It paved the way towards Inmarsat-Mini-M. Mini-M: The Mini-M is a compact, light-weight satellite phone with a long battery life (48 hour standby and 2.5 hour 'talk' time). provides voice services at 4.8 kbit/s and medium speed fax/data services at 2.4 kbit/s.

57. 57 Automatic Identification System, AIS The Automatic Identification System (AIS) is a system used by ships and Vessel Traffic Services (VTS) principally for identification and locating vessels. AIS provides a means for ships to electronically exchange ship’s data. This information can be displayed in a tabular format on a stand-alone instrument screen or as an overlay on an electronic chart plotter and/or radar screen. AIS is intended to assist the ship’s crew and allow maritime authorities to track and monitor vessel movements. It works by connecting a radio transponder with an electronic navigation system such as GPS and other ship’s sensors.

58. 58 AIS There are two major classes of AIS units: Class A – An active system broadcasting ship’s data. Required on “Compulsory” vessels (and others in some countries). Class B – A passive receive only system for non-compulsory and recreational vessels.

59. 59 AIS A Class A AIS unit broadcasts the following information every 2 to 10 seconds while underway, and every 3 minutes while at anchor at a power level of 12.5 watts. The information broadcast includes: MMSI number Navigation status (as defined by the COLREGS - not only are "at anchor" and "under way using engine" currently defined, but "not under command" is also currently defined) Rate of turn - right or left, 0 to 720 degrees per minute (input from rate-of-turn indicator) Speed over ground Position accuracy – dependent upon position source Position - Latitude and Longitude Course over ground - relative to true north True Heading Universal Time that the information was broadcast

60. 60 AIS In addition, the Class A AIS unit broadcasts the following information every 6 minutes: MMSI number IMO number - unique identification (related to ship's construction, similar to an automobile’s VIN) Radio call sign - international call sign assigned to vessel, often used on voice radio Name of Vessel – limited to 20 characters Type of ship/cargo Dimensions of ship - to nearest meter Location on ship where reference point for position reports is located Type of position fixing device Draught of ship - 1/10 meter to 25.5 meters Destination – limited to 20 characters Estimated time of Arrival at destination - month, day, hour, and minute in UTC

61. 61 AIS AIS limitation Your AIS display shows only the data from the Class A AIS transponders. This is generally limited to large commercial shipping. Smaller, non-compulsory vessels, recreational vessels, and military vessels do not broadcast their ship’s information

62. 62 End of Seminar Slides to follow are information only

63. 63 GMDSS Functional Requirements Transmit Ship-to-shore distress alerts by two separate and independent means using a different radio communication service Receive ship-to-shore distress alerts Transmit and receive ship-to-ship distress alerts Transmit and receive SAR coordinating communications

64. 64 GNDSS Functional Requirements Transmitting and receiving on-scene communications Transmitting and receiving signals for locating Transmitting and receiving maritime safety information Transmitting and receiving general communications Transmitting and receiving bridge-to-bridge communications

65. 65 Satellite Coverage

66. 66 EPIRBs without internal GPS When the beacon has no GPS receiver, the system locates the beacon from its Doppler shift as received by the quickly-moving satellites. Using the same techniques as radar, basically, the frequency received varies depending on the speed of the beacon relative to the satellite. The amount of shift is proportional to the range and bearing to the satellite. The instant the beacon's Doppler shift changes from high to low indicates the time when the bearing from the beacon to the satellite's ground track is 90 degrees. The side of the satellite track is determined because the rate of change of the Doppler shift is faster when the Earth is turning towards the satellite track. One key to an effective Doppler position triangulation is excellent frequency stability. If the signal is not monotone (stable), then the results of the triangulation will vary. This is why 406 MHz beacons can be triangulated to within 5km and the b-side (unlikely mirror position) can be ruled out with 98.5% accuracy, whereas the old technology of analog beacons is only accurate to within a 20 km radius per mirror image, each of which is roughly equally likely to be the correct position. In order to handle multiple simultaneous beacons, modern 406 MHz beacons transmit in bursts, and remain silent for a few seconds. This also conserves transmitter power. Russia developed the original system, and its success drove the desire to develop the improved 406 MHz system. The original system is a brilliant adaptation to the low quality beacons, originally designed to aid air searches. It uses just a simple, lightweight transponder on the satellite, with no digital recorders or other complexities. Ground stations listen to each satellite as long as it is above the horizon. Doppler shift is used to locate the beacon(s). Multiple beacons are separated when a computer program performs a Fourier transform on the signal. Also, two satellite passes per beacon are used. This eliminates false alarms by using two measurements to verify the beacon's location from two different bearings. This prevents false alarms from VHF channels that affect a single satellite. Regrettably, the second satellite pass almost doubles the average time before notification of the rescuing authority. However, the notification time is much less than a day.

67. 67 Search and Rescue Transponders (SART) How do they work? A SART has a receiver which scans for UHF signals between 9.2 and 9.5 GHz - the frequencies on which an X-band radar transmits its signal. As soon as the SART detects a signal it immediately transmits its own signal on the same frequency. This signal consists of a series of twelve pulses, and these are displayed on the screen of the radar as a series of twelve echoes with a gap of 0.6 miles between each of them. The first dot is at the position of the SART, with the remainder radiating in a straight line towards the edge of the screen.As the rescue vessel approaches the SART, the twelve dots each become short arcs. These arcs increase in size as the vessel gets closer, until the signal from the SART is permanently activated by the weakest side-lobes from the radar transmission. The signal from the SART becomes twelve concentric circles on the radar screen and this tells the would-be rescuers that they have more or less arrived.When a SART is switched on it will show a light to indicate that it is working. An approved SART should have sufficient power to operate in this stand-by mode for at least 96 hours. When it receives a signal from an X-band radar, and transmits its own signal, it will either flash this indicating light or in some cases a second light or even a buzzer. This will serve to let the distressed persons know that an approaching radar is activating the SART. If the survivors have a handheld VHF with them then this would be a good time to use it to try calling the approaching ship.Since the radar UHF signals can only effectively travel in a straight line, the distance from which a SART can be activated by a radar is dependent on its own height and the height of the interrogating radar scanner. Most SARTs have an extendible handle to help in positioning it as high as possible in the liferaft or lifeboat. The SART must be secured outside the canopy of the liferaft. Operating it from inside the liferaft will greatly reduce its effectiveness. The International Maritime Organisation stipulates that a SART mounted at a height of one metre must be detectable by a ship's radar with a scanner height of 15 metres at ,distance of at least 5 miles.It has been found from tests that a ship's radar will usually detect a SART laying flat on the floor of a liferaft at around 1.8 miles. If the SART is upright on the floor the detection range increases to about 2.5 miles. It should be possible, under most conditions, to mount the SART at least two metres high. A normal detection range for a SART mounted two metres above sea level by an average ship's radar is about seven to ten miles. However, a search aircraft equipped with an X-band radar should be able to detect it from at least 30 miles when flying at an altitude of around 3,000 feet.All SARTs should be checked on a weekly basis for any physical damage and for the expiration date of the battery. This is normally indicated on the manufacturer's plate affixed to the SART. It is permitted to check the operation of a SART by briefly turning it on and exposing it to the transmissions of the ship's radar. If this is done on board, then the radar screen will be flooded with the concentric circles, showing the proximity of the SART. Such tests should be conducted on a monthly basis and should be kept short so as not to shorten the life of the battery too much and to reduce the risk of other vessels seeing it, resulting in a false distress alert. Ideally, such tests should be conducted when there are no other vessels within radar range so as not to cause interference or false alarms.Vessels which are using their radar to look for a SART should use a range of 6 or 12 miles on the radar for optimum results. If a shorter range is selected, the narrower bandwidth used in the receiver will reduce the brightness of the dots making them harder to see. There is no point in using a longer range, since the maximum distance a SART will be detectable from another vessel is 7 to 10 miles.There are some SARTs which have a so-called anti-collision mode. When operated in this mode they transmit five pulses instead of the normal twelve. Such a unit may well help the radar operator on an approaching ship to see you, but there is a danger that it might be mistaken for the distress signal and the ship may possibly try to rescue you, even if you were not in distress. Such use of a SART is not encouraged.Under distress conditions though, there is no doubt that a SART is a valuable aid for any vessel to carry. It will greatly facilitate any search and rescue operation. Ends

68. 68 Current INMARSAT Services 'Mini-M' (INMARSAT-phone) service:  The Mini-M is a compact, light-weight satphone with a long battery life (48 hour standby and 2.5 hour 'talk' time).  Service includes direct-dial phone, fax and 2400 baud data on an all digital communications channel. (See Personal Satellite Telephones ). see pop-up How Satellite Telephones Work 'M4'  Service:   M4 type terminals are light-weight (9 pounds), all-digital voice + high-speed data phones.  Being highly mobile devices, M4s provide traditional high-quality voice and 64 Kbps High Speed Data transmission.  M4 satphones open up a new era of personal mobile office communication. 'B' Service:   For the past 3 years B service has provided a digital channel for a range of transmission opportunities, including high quality (16 Kbps) voice, Group-III fax at 9.6 Kbps, and data at 9.6 Kbps and 56/64 Kbps. This latter 56/64 Kbps is an all-digital Duplex High Speed Data (DHSD) link that opens a whole array of capabilities for Inmarsat users.Other services include:  'Standard M' (the original personal mobile phone service);  'C' (marine messaging);  'D' (two way global messaging and multicasting); and various services for aircraft. Since January 2000 , Inmarsat has broadened its total satellite service portfolio, entering the fixed satellite market by providing VSAT system integration solutions; offering maritime e-mail and automated data communications systems and an e-commerce maritime venture providing a web portal for on-board supplies and service procurement.