DYNAMIC POSITIONING

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A Dynamic Positioning Ship is very helpful in monitoring the natural occurrences that take place offshore and aids in ships to maintain its position in the deep sea by pinpointing about the wind and the wave data which would otherwise make a ship lose control and veer off its course. Through Dynamic Positioning, a ship does not require the usage of anchors to maintain its course in the deep waters and thus can carry out its main purpose well. Ships with dynamic positioning system are known as dynamic positioning ships. Dynamic positioning (DP) is a computer-controlled system to automatically maintain a vessel's position and heading by using its own propellers and thrusters. Position reference sensors, combined with wind sensors, motion sensors and gyro compasses, provide information to the computer pertaining to the vessel's position and the magnitude and direction of environmental forces affecting its position. Examples of vessel types that employ DP include, but are not limited to, ships and semi-submersible mobile offshore drilling units (MODU), oceanographic research vessels and cruise ships.
The computer program contains a mathematical model of the vessel that includes information pertaining to the wind and current drag of the vessel and the location of the thrusters. This knowledge, combined with the sensor information, allows the computer to calculate the required steering angle and thruster output for each thruster. This allows operations at sea where mooring or anchoring is not feasible due to deep water, congestion on the sea bottom (pipelines, templates) or other problems.
Dynamic positioning may either be absolute in that the position is locked to a fixed point over the bottom, or relative to a moving object like another ship or an underwater vehicle. One may also position the ship at a favorable angle towards wind, waves and current, called weathervaning.

How Dynamic Positioning Ships Work?
The working of a Dynamic Positioning Ship is quite simple. There is a control panel which notes the wind and the wave fluctuation and accordingly sends appropriate signals to the propellers so as to enable the ship to steady and maintain its course. There are, however three different levels of Dynamic Positioning that can be used and it depends on the type of the ship on which Dynamic Positioning has to be enabled.
Level I Dynamic Positioning System
Ships whose off-course drifting will not have any impact on the life of the crew or on any marine creature are generally enabled with a Level I Dynamic Positioning System. This is the most basic Dynamic Positioning system and it does not have any advanced tools that ships with the other two Dynamic Positioning systems require.
Level II Dynamic Positioning System
A Level II Dynamic Positioning system in built in a ship whose off-course veering will tend to cause serious problems. A Dynamic Positioning Ship enabled with a Level II Dynamic Positioning system contains high-end computer applications and diving watercrafts in case the ship encounters any major problem in the deep sea.
Level III Dynamic Positioning System
A Dynamic Positioning Ship with a Level III Dynamic Positioning contains similar equipments like a Level II Dynamic Positioning system but with a back-up Dynamic Positioning system at some other location. The aspect of back-up is important because they will act as emergencies in case the main Dynamic Positioning system gets destroyed due to any water penetration or occurrence of fire or short circuit or any other inadvertent casualty. Generally oil tankers which drill in the deep parts of the ocean are equipped with a Level III Dynamic Positioning system.
At present, only a few elite ships and naval vessels incorporate the usage of Dynamic Positioning. But since conserving and preserving the environment and the eco-system has become the need of the hour, it is only logical that Dynamic Positioning becomes the future of marine vessels in order to preserve the marine ecology with every bit of technological knowledge man has in his power and disposal.
Dynamic Positioning is generally used in research ships and drilling vessels which have to venture into the deepest parts of the ocean and sea where winds and waves tend to be perpetually altering. In situations like this, it could prove very tedious for a ship’s crew to lay the anchors. A ship enabled with Dynamic Positioning can get to know about the changes in the wind and the waves and thus alter its course suitably without having to compromise on its main purpose.

Ships enabled with Dynamic Positioning are independent of anchors and other support system in the sense that a Dynamic Positioning Ship enables the use of pushers and propellers to make the ship stay on course and steady rather than get carried away by the fluctuating winds and waves. This is perhaps the most advantageous feature of the system of Dynamic Positioning. In the earlier days, when ships used to enter the deeper parts of the ocean and the seas, there always used to be a threat of ships colliding with another ship because of natural movement of the wind and the waves or ships veering off course and thus getting lost and never to be found. But since the development of Dynamic Positioning which incorporates the usage of SONAR, Radar and other comprehensive detection, ships have started finding it easy to maintain their pace and steady their being in the deeper parts of the oceanic and sea waters.

DP operator

The DP operator (DPO) judges whether there is enough redundancy available at any given moment of the operation. IMO issued MSC/Circ.738 (Guidelines for dynamic positioning system (DP) operator training) on 24-06-1996. This refers to IMCA (International Marine Contractors Association) M 117 as acceptable standard.

To qualify as a DP operator the following path should be followed:

1. a DP Induction course
2. a minimum of 30 days seagoing DP familiarisation
3. a DP Advanced course
4. a minimum of 180 days watchkeeping on a DP ship
5. a statement of suitability by the master of a DP ship

When the watchkeeping is done on a Class 1 DP ship, a limited certificate will be issued; otherwise a full certificate will be issued.

The DP training and certification scheme is operated by The Nautical Institute (NI). The NI issue logbooks to trainees, they accredit training centres and control the issuance of certification.

With ever more DP ships and with increasing manpower demands, the position of DPO is gaining increasing prominence. This shifting landscape led to the creation of The International Dynamic Positioning Operators Association (IDPOA) in 2009. www.dpoperators.org

IDPOA membership is made up of certified DPO's who qualify for fellowship (fDPO), while Members (mDPO) are those with DP experience or who may already be working within the DP certification scheme

Class requirements

Based on IMO (International Maritime Organization) publication 645 the Classification Societies have issued rules for Dynamic Positioned Ships described as Class 1, Class 2 and Class 3.

• Equipment Class 1 has no redundancy.
  Loss of position may occur in the event of a single fault.

• Equipment Class 2 has redundancy so that no single fault in an active system will cause the system to fail.
  Loss of position should not occur from a single fault of an active component or system such as generators, thruster, switchboards, remote controlled valves etc., but may occur after failure of a static component such as cables, pipes, manual valves etc.

• Equipment Class 3 which also has to withstand fire or flood in any one compartment without the system failing.
  Loss of position should not occur from any single failure including a completely burnt fire sub division or flooded watertight compartment.

Redundancy is the ability to cope with a single failure without loss of position. A single failure can be, amongst others:

• Thruster failure
• Generator failure
• Powerbus failure (when generators are combined on one powerbus)
• Control computer failure
• Position reference system failure
• Reference system failure

For certain operations redundancy is not required. For instance, if a survey ship loses its DP capability, there is normally no risk of damage or injuries. These operations will normally be done in Class 1.

For other operations, such as diving and heavy lifting, there is a risk of damage or injuries. Depending on the risk, the operation is done in Class 2 or 3. This means at least three Position reference systems should be selected. This allows the principle of voting logic, so the failing PRS can be found. For this reason, there are also three DP control computers, three gyrocompasses, three MRU’s and three wind sensors on Class 3 ships. If a single fault occurs that jeopardizes the redundancy, i.e., failing of a thruster, generator or a PRS, and this cannot be resolved immediately, the operation should be abandoned as quickly as possible.

To have sufficient redundancy, enough generators and thrusters should be on-line so the failure of one does not result in a loss of position. This is left to the judgement of the DP operator. For Class 2 and Class 3 a Consequence Analyses should be incorporated in the system to assist the DPO in this process.

Disadvantage is that a generator can never operate at full load, resulting in less economy and fouling of the engines.

The redundancy of a DP ship should be judged by a failure mode and effects analysis (FMEA) study and proved by FMEA trials. Besides that, annual trials are done and normally DP function tests are completed prior to each project

About BNWAS

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What is BNWAS?

The term BNWAS is an acronym for the term Bridge Navigational Watch Alarm System - a safety system made mandatory in amendments to SOLAS Chapter V Regulation 19 and adopted on 5th June 2009 by Resolution MSC.282(86).

Why Do You Need a BNWAS?

As outlined in the performance standards MSC.128(75):
"The purpose of the bridge navigational watch alarm system (BNWAS) is to monitor bridge activity and detect operator disability which could lead to marine accidents. The system monitors the awareness of the Officer of the Watch (OOW) and automatically alerts the Master or another qualified OOW if for any reason the OOW becomes incapable of performing the OOW's duties.
This purpose is achieved by a series of indications and alarms to alert first the OOW and, if he is not responding, then to alert the Master or another qualified OOW. Additionally, the BNWAS may provide the OOW with a means of calling for immediate assistance if required. The BNWAS should be operational whenever the ship's heading or track control system is engaged, unless inhibited by the Master."

IMO - Solas Chapter V Regulation 19

The requirements making it mandatory to have a bridge navigational watch alarm system (BNWAS) fitted to all passenger and cargo vessels can be found in the amendments made to SOLAS Chapter V Regulation 19 that were adopted by the IMO on 5th June 2009 in Resolution MSC.282(86).
The changes see the following subparagraph is added to paragraph 2.2 of the regulations:

.3 a bridge navigational watch alarm system (BNWAS), as follows:

.1 cargo ships of 150 gross tonnage and upwards and passenger ships irrespective of size constructed on or after 1 July 2011;

.2 passenger ships irrespective of size constructed before 1 July 2011, not later than the first survey* after 1 July 2012;

.3 cargo ships of 3,000 gross tonnage and upwards constructed before 1 July 2011, not later than the first survey* after 1 July 2012;

.4 cargo ships of 500 gross tonnage and upwards but less than 3,000 gross tonnage constructed before 1 July 2011, not later than the first survey* after 1 July 2013; and

.5 cargo ships of 150 gross tonnage and upwards but less than 500 gross tonnage constructed before 1 July 2011, not later than the first survey* after 1 July 2014.

The bridge navigational watch alarm system shall be in operation whenever the ship is underway at sea;

.4 a bridge navigational watch alarm system (BNWAS) installed prior to 1 July 2011 may subsequently be exempted from full compliance with the standards adopted by the Organization, at the discretion of the Administration."

BNWAS Performance Standards 

MSC.128(75) - IMO BNWAS Performance Standards

It is essential that any BNWAS that you choose for your vessel meets with the performance standards set out by the IMO.
The performance standards for a bridge navigational watch alarm system (BNWAS) were outlined in Resolution MSC.128(75) and will form the basis of any Type Approval.

IEC 62616:2010 - International Performance Standards

IEC is the world's leading organisation of international standards for all electrical, electronic and related technologies. IEC 62616:2010(E) specifies the minimum performance requirements, technical characteristics and methods of testing, and required test results, for a bridge navigational watch alarm system (BNWAS) as required by Chapter V of the International Convention for the Safety of Life at Sea (SOLAS), as amended. It takes account of the general requirements given in IMO resolution A.694(17) and is associated with IEC 60945. When a requirement in this International Standard is different from IEC 60945, the requirement in this standard takes precedence.
This standard incorporates the parts of the performance standards included in IMO resolution
MSC.128(75).

STCW 2010 MANILA AMMENDMENTS

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1 Introduction

1.1  The STCW Convention 1978 has been amended by the 2010 Manila Amendments and contains new requirements for all seafarers. Seafarers revalidating their Certificates of Competency (CoC) will be required to submit additional evidence to ensure their Certificate is valid for service on certain types of ships after 31 December 2016.  


2. Training Requirements

2.1  Deck Certificate of Competency Revalidation, ECDIS requirements
The MCA does not currently accept any distance learning courses
The 2010 Manila Amendments to the STCW Code bring in the requirement for Deck Officers working onboard ships fitted with an Electronic Chart Display Information System (ECDIS) to undergo specific education and training.
As of 1 January 2012 seafarers requiring revalidation of UK CoCs issued in compliance with STCW Regulation II/1, II/2 and II/3 (maintain a safe navigational watch; use of ECDIS to maintain safety of navigation; and maintain the safety of navigation through the use of ECDIS and associated navigation systems to assist command decision making) need to comply with the new STCW requirements to ensure their CoC remains valid on ships fitted with ECDIS after 31 December 2016.

For the revalidation of UK CoC valid after 31 December 2016, the seafarer must have completed one of the following:

•  MCA approved Navigation Radar and ARPA Simulator (NARAS)/ Navigation Aids and Equipment and Simulator Training (NAEST) (Operational Level) course completed on or after 1January 2005; or
•  MCA approved NARAS/ NAEST (Management Level) course completed on or after 1January 2005; or
•  MCA approved ECDIS course completed on or after 1 January 2005; or
•  ECDIS simulator training course in compliance with IMO Model Course 1.27, accepted by the MCA and approved by an Administration whose CoC we accept for the issue of a CEC.

The original course certificate must be submitted with the application. Deck Officers not meeting the above requirement will receive the following CoC limitation:

“From the 1 January 2017 this certificate is not valid for service on ships fitted with ECDIS”.

Deck Officers may subsequently request the removal of this limitation by providing documentary evidence of MCA approved ECDIS training.   

2.2 Engineering Certificate of Competency Revalidation, High Voltage (HV) requirements

The 2010 Manila Amendments to the STCW Code bring in the requirement for engineers to undergo education and training in High Voltage systems, at both the operational and management levels. This requirement comes into force on the 1 January 2017 but will affect the revalidation of Engineering Certificates of Competency (CoC) from 1 January 2012. There is no requirement for additional training to be undertaken by all existing Engineer Officers, whether or not they intend to work on ships having High Voltage systems. However, High Voltage training requirements will be incorporated in the future training programmes of Engineer Officers at both the operational and management levels.

No additional action is required for Engineer Officers who do not work on and do not intend to work on ships with High Voltage systems. These Engineer Officers will receive the following CoC limitation:

“From 1 January 2017 this certificate is not valid for service on ships fitted with High Voltage (over 1000V) systems”.

Engineer Officers who do not want this limitation placed on their CoC should read the following section applicable to their Certificate.

Note: A High Voltage (over 1000V) system is where voltage is generated and distributed at high voltage or transformed to and distributed at high voltage. It does not include systems where high voltage is utilised locally e.g. ignition systems, radio transmission, Radar and other navigational equipment.

EOOW CoC Reg. III/1 (Operational Level)

To avoid having the High Voltage limitation, Engineer Officers of the Watch will need to show compliance with the 2010 Manila Amendments. In addition to the current revalidation requirements, they will have to provide documentary evidence of:

•  completion of High Voltage (HV) course(*); or
•  completion of the following sea service in the engine room on vessels fitted with HV systems;
•  six months in the preceding five years; or
•  three months sea service during the last twelve months.

Sea service evidence can be provided in the form of a company letter signed by an authorised official within the company.

Second/Chief Engineer Officer CoC Reg. III/2 and III/3 (Management Level)

To avoid having the High Voltage limitation, Senior Engineer Officers will need to show compliance with 2010 Manila Amendments. In addition to the current revalidation requirements, they will have to provide documentary evidence of completion of High Voltage (HV) course (*).

* High Voltage Courses

Courses previously undertaken prior to 1 July 2013 do not need to be MCA approved but you must provide documentary evidence confirming the course covers at least the following topics:

at the operational level
•  The hazards associated with High Voltage systems;
•  The functional, operational and safety requirements for a marine high-voltage system;
•  Basic arrangement of High Voltage systems and their protective devices;
•  Safety procedures related to High Voltage systems; and
•  Immediate actions to be taken under fault conditions.
at the management level
•  The functional, operational and safety requirements for a marine high-voltage system;
•  Assignment of suitably qualified personnel to carry out maintenance and repair of high-voltage switchgear of various types;
•  Taking remedial action necessary during faults in a high-voltage system;
•  Producing a switching strategy for isolating components of a high-voltage system;
•  Selecting suitable apparatus for isolation and testing of high-voltage equipment;
•  Carrying out a switching and isolation procedure on a marine high-voltage system, complete with safety documentation; and
•  Performing tests of insulation resistance and polarization index on high-voltage equipment.

The original certificate and course syllabus must be submitted with the application.

Engineer Officers may subsequently request the removal of the High Voltage limitation by providing documentary evidence of a High Voltage training course that includes the required topics.  


2.3 Updating-Refresher Training Requirements
The 2010 Manila Amendments to the STCW Code bring in new requirements for seafarers required to hold any of the following safety training courses:
•  Personal Survival Techniques (STCW Table A-VI/1-1)
•  Fire Prevention and Fire Fighting (STCW Table A-VI/1-2)
•  Proficiency in Survival Craft and Rescue Boats Other Than Fast Rescue Boats (STCW Table A-VI/2-1)
•  Proficiency in Fast Rescue Boats (STCW Table A-VI/2-2)
•  Advanced Fire Fighting (STCW Table A-VI/3)

Seafarers required to hold any of the above certificates of proficiency shall, every five years, provide evidence of having maintained the required standard of competence, to undertake the tasks, duties and responsibilities specified in the above stated tables.

Seafarers revalidating their Certificates of Competency (CoC) after 1 January 2017 will be required to submit documentary evidence of having completed MCA approved updating-refresher training.  There is no requirement to provide documentary evidence for having completed updating-refresher training if a seafarer applies for CoC revalidation before 1 January 2017.

From 1 January 2017 Port State Control Officers may require seafarers to provide documentary evidence of having maintained the required standard of competence, to undertake the tasks, duties and responsibilities listed above.
Presenting the documentary evidence obtained on completing an MCA approved updating-refresher course will meet this requirement.

Details of updating-refresher training will be published in a separate Marine Information Notice.

2.4  Leadership and Management Requirements

The 2010 Manila Amendment to the STCW Code brings in new requirements for Leadership and Management.  Additional education and training in human element, leadership and management will be introduced into the UK Certification structure before 1 July 2013. It is considered that seafarers meeting the current Certificate of Competency revalidation requirements will have gained sufficient leadership and management skills not to require further training.

3. Tanker Endorsement Requirements

3.1  The 2010 Manila Amendments define continued professional competence for seafarers revalidating tanker endorsements under Regulation I/11 as:   

•  Approved seagoing service, performing duties appropriate to the tanker certificate or endorsement held, for a period of at least 3 months in total in the proceeding 5 years; or
•  Successfully completing an approved relevant training course or courses.

As of 1 January 2012 seafarers revalidating tanker endorsements, in addition to the current revalidation requirements, must provide evidence of approved tanker sea service appropriate to the endorsement(s) in their CoC.  Evidence must be submitted in the form of original sea service testimonials or an original MCA approved course certificate as per MGN 9.

Seafarers unable to provide evidence appropriate to a tanker endorsement in their CoC, but able to demonstrate the current revalidation requirements for tanker endorsements, will have that tanker endorsement revalidated until 31 December 2016.  Depending on the tanker endorsement(s) that cannot be revalidated past 31 December 2016 they will receive the appropriate limitation(s) in their CoC:

For Oil:
“From 1 January 2017 this certificate is not valid for service on Oil Tankers”

For Chemical:
“From 1 January 2017 this certificate is not valid for service on Chemical Tankers”

For Gas:
“From 1 January 2017 this certificate is not valid for service on Gas Tankers”

For Vegetable Oil
“From 1 January 2017 this certificate is not valid for service on Vegetable Oil Tankers”

Seafarers may subsequently request the removal of the tanker limitation by providing documentary evidence of approved training or appropriate sea service.   

4.  Sea Time Requirements

4.1 In addition to sea time requirements listed in MGN 9 the 2010 Manila Amendments allow Certificates of Competency to be revalidated if the seafarer has approved sea going service, performing functions appropriate to the certificate held for a period of at least:  

•  Three months in total during the preceding six months immediately prior to revalidating.

In addition to the current revalidation requirements, seafarers providing evidence of three months sea service within six months immediately prior to their application will be eligible for revalidation.   


5. Validity Periods

5.1 The 2010 Manila Amendments allow an application for revalidation of a Certificate of Competency (CoC) made within six months of the certificates expiry date to be revalidated until the fifth anniversary of the certificates expiry date.  

Providing the current revalidation requirements are met, Certificates of Competency received for revalidation within a period six months prior to expiring shall be revalidated until the fifth anniversary of the current CoC expiry date.  Certificates received outside of this six months period will be revalidated for five years from the date of revalidation.  

6. Removal of Limitations

6.1 Seafarers providing the appropriate documentary evidence with their application for a Certificate of Competency revalidation will have the limitation(s) removed with no additional fee. Alternatively, the limitation(s) can be removed by submitting the appropriate documentary evidence and the fee for the upgrade of Certificate of Competency.

MARINESHELF publishes articles contributed by seafarers and other marine related sites solely for the benefit of seafarers .All copyright materials are owned by its respective authors or publishers.

 Components of GMDSS

The main types of equipment used in GMDSS are:

Emergency Position-Indicating Radio Beacon (EPIRB)

Main article: Emergency Position-Indicating Radio Beacon

Cospas-Sarsat is an international satellite-based search and rescue system, established by Canada, France, the United States, and Russia. These four countries jointly helped develop the 406 MHz Emergency Position-Indicating Radio Beacon (EPIRB), an element of the GMDSS designed to operate with Cospas-Sarsat system. These automatic-activating EPIRBs, now required on SOLAS ships, commercial fishing vessels, and all passenger ships, are designed to transmit to a rescue coordination center a vessel identification and an accurate location of the vessel from anywhere in the world. Newest designs incorporate GPS receivers to transmit highly accurate positions of distress.

 NAVTEX

Main article: Navtex

Navtex is an international, automated system for instantly distributing maritime navigational warnings, weather forecasts and warnings, search and rescue notices and similar information to ships. A small, low-cost and self-contained "smart" printing radio receiver installed in the pilot house of a ship or boat checks each incoming message to see if it has been received during an earlier transmission, or if it is of a category of no interest to the ship's master. The frequency of transmission of these messages is 518 kHz in English, while 490 kHz is use to broadcast in local language.
The messages are coded with a header code identified by the using alphabets to represent broadcasting stations, type of messages, and followed by two figures indicating the serial number of the message.

 Inmarsat

Satellite systems operated by the Inmarsat, under contract to the International Mobile Satellite Organization (IMSO), are also important elements of the GMDSS. Four types of Inmarsat ship earth station terminals are recognized by the GMDSS: the Inmarsat A, B, C and F77. The Inmarsat B and F77, an updated version of the A, provide ship/shore, ship/ship and shore/ship telephone, telex and high-speed data services, including a distress priority telephone and telex service to and from rescue coordination centers. The F77 is meant to be used with the Inmarsat C, since its data capability does not meet GMDSS requirements. The Inmarsat C provides ship/shore, shore/ship and ship/ship store-and-forward data and email messaging, the capability for sending preformatted distress messages to a rescue coordination center, and the Inmarsat C SafetyNET service. The Inmarsat C SafetyNET service is a satellite-based worldwide maritime safety information broadcast service of high seas weather warnings, NAVAREA navigational warnings, radionavigation warnings, ice reports and warnings generated by the USCG-conducted International Ice Patrol, and other similar information not provided by NAVTEX. SafetyNET works similarly to NAVTEX in areas outside NAVTEX coverage.
Inmarsat C equipment is relatively small and lightweight, and costs much less than an Inmarsat A, B or F77. Inmarsat A, B and F77 ship earth stations require relatively large gyro-stabilized antennas; the antenna size of the Inmarsat C is much smaller. Inmarsat also operates an EPIRB system, the Inmarsat L, which is similar to that operated by COSPAS-SARSAT. The INMARSAT L (also called INMARSAT E) EPIRB system is terminated by November 30th, 2006. The INMARSAT EPIRBs are replaced by COSPAS-SARSAT EPIRBs with built-in GPS. Immediate alerting is possible through the GEOSAR satellites of the COSPAS-SARSAT system.
In July 2002 IMSO notified IMO of the decision by Inmarsat to withdraw provision of Inmarsat A services as from 31 December 2007. On that date, Inmarsat A can no longer be used for any purpose. The last type approval by Inmarsat for a new model of maritime Inmarsat A mobile earth station was granted in 1991, since then no new Inmarsat A models have been approved.
Under a cooperative agreement with the National Oceanic and Atmospheric Administration (NOAA), combined meteorological observations and AMVER reports can now be sent to both the USCG AMVER Center, and NOAA, using an Inmarsat C ship earth station, at no charge. .
SOLAS now requires that Inmarsat C equipment have an integral satellite navigation receiver, or be externally connected to a satellite navigation receiver. That connection will ensure accurate location information to be sent to a rescue coordination center if a distress alert is ever transmitted.

 High Frequency

The GMDSS includes High Frequency (HF) radiotelephone and radiotelex (narrow-band direct printing) equipment, with calls initiated by digital selective calling (DSC). Worldwide broadcasts of maritime safety information are also made on HF narrow-band direct printing channels.

 Search and Rescue Transponder

Main article: Search and Rescue Transponder

The GMDSS installation on ships include one or more Search and Rescue Transponder (SART) devices which are used to locate survival craft or distressed vessels by creating a series of dots on a rescuing ship's 3 cm radar display. The detection range between these devices and ships, dependent upon the height of the ship's radar mast and the height of the SART, is normally about 15 km (8 nautical miles). Note that a marine radar may not detect a SART even within this distance, if the radar settings are not optimized for SART detection.
On detected by a radar, the SART will produce a visual and aural indication.

 Digital Selective Calling

The IMO also introduced Digital Selective Calling (DSC) on MF, HF and VHF maritime radios as part of the GMDSS system. DSC is primarily intended to initiate ship-to-ship, ship-to-shore and shore-to-ship radiotelephone and MF/HF radiotelex calls. DSC calls can also be made to individual stations, groups of stations, or "all stations" in one's reach. Each DSC-equipped ship, shore station and group is assigned a unique 9-digit Maritime Mobile Service Identity.
DSC distress alerts, which consist of a preformatted distress message, are used to initiate emergency communications with ships and rescue coordination centers. DSC was intended to eliminate the need for persons on a ship's bridge or on shore to continuously guard radio receivers on voice radio channels, including VHF channel 16 (156.8 MHz) and 2182 kHz now used for distress, safety and calling. A listening watch aboard GMDSS-equipped ships on 2182 kHz ended on February 1, 1999. In May 2002, IMO decided to postpone cessation of a VHF listening watch aboard ships. That watchkeeping requirement had been scheduled to end on 1 February 2005.
IMO and ITU both require that the DSC-equipped MF/HF and VHF radios be externally connected to a satellite navigation receiver. That connection will ensure accurate location information is sent to a rescue coordination center if a distress alert is ever transmitted. The FCC requires that all new VHF and MF/HF maritime radiotelephones type accepted after June 1999 have at least a basic DSC capability.
VHF digital selective calling also has other capabilities beyond those required for the GMDSS. The Coast Guard uses this system to track vessels in Prince William Sound, Alaska, Vessel Traffic Service. IMO and the USCG also plan to require ships carry a Universal Shipborne Automatic Identification System, which will be DSC-compatible. Countries having a GMDSS A1 Area should be able to identify and track AIS-equipped vessels in its waters without any additional radio equipment. A DSC-equipped radio cannot be interrogated and tracked unless that option was included by the manufacturer, and unless the user configures it to allow tracking.
GMDSS telecommunications equipment should not be reserved for emergency use only. The International Maritime Organization encourages mariners to use that equipment for routine as well as safety telecommunications.

 GMDSS Sea Areas

GMDSS sea areas serve two purposes: to describe areas where GMDSS services are available, and to define what GMDSS ships must carry. Prior to the GMDSS, the number and type of radio safety equipment ships had to carry depended upon its tonnage. With GMDSS, the number and type of radio safety equipment ships have to carry depend upon the areas in which they travel. GMDSS sea areas are defined by governments.
In addition to equipment listed below, all GMDSS-regulated ships must carry a satellite EPIRB, a NAVTEX receiver (if they travel in any areas served by NAVTEX), an Inmarsat-C SafetyNET receiver (if they travel in any areas not served by NAVTEX), a DSC-equipped VHF radiotelephone, two or more VHF handhelds, and a search and rescue radar transponder (SART).

 Sea Area A1

An area within the radiotelephone coverage of at least one VHF coast station in which continuous digital selective calling (Ch.70/156.525Mc.) alerting and radiotelephony services are available.Such an area could extend typically 20 nautical miles (37 km) to 30 nautical miles (56 km) from the Coast Station.

Sea Area A2

An area, excluding Sea Area A1, within the radiotelephone coverage of at least one MF coast station in which continuous DSC (2187.5 kHz) alerting and radiotelephony services are available.For planning purposes this area typically extends to up to 100 nautical miles (190 km) offshore,but would exclude any A1 designated areas.In practice,satisfactory coverage may often be achieved out to around 400 nautical miles (740 km) offshore.

 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.This area lies between about latitude 76 Degree NORTH and SOUTH,but excludes A1 and/or A2 designated areas.

 Sea Area A4

An area outside Sea Areas A1, A2 and A3 is called Sea Area A4. This is essentially the polar regions, north and south of about 76 degrees of latitude, excluding any other areas.

 GMDSS Radio Equipment Required for U.S. Coastal Voyages

Presently, until an A1 or A2 Sea Area is established, GMDSS-mandated ships operating off the U.S. coast must fit to Sea Areas A3 (or A4) regardless of where they operate. U.S. ships whose voyage allows them to always remain within VHF channel 16 coverage of U.S. Coast Guard stations may apply to the Federal Communications Commission for an individual waiver to fit to Sea Area A1 requirements. Similarly, those who remain within 2182 kHz coverage of U.S. Coast Guard stations may apply for a waiver to fit to Sea Area A2 requirements.

 History

Since the invention of radio at the end of the 19th century, ships at sea have relied on Morse code, invented by Samuel Morse and first used in 1844, for distress and safety telecommunications. The need for ship and coast radio stations to have and use radiotelegraph equipment, and to listen to a common radio frequency for Morse encoded distress calls, was recognized after the sinking of the liner RMS Titanic in the North Atlantic in 1912. The U.S. Congress enacted legislation soon after, requiring U.S. ships to use Morse code radiotelegraph equipment for distress calls. The International Telecommunications Union (ITU), now a United Nations agency, followed suit for ships of all nations. Morse encoded distress calling has saved thousands of lives since its inception almost a century ago, but its use requires skilled radio operators spending many hours listening to the radio distress frequency. Its range on the medium frequency (MF) distress band (500 kHz) is limited, and the amount of traffic Morse signals can carry is also limited.
Not all ship-to-shore radio communications were short range. Some radio stations provided long-range radiotelephony services, such as radio telegrams and radio telex calls, on the HF bands (3-30 MHz) enabling worldwide communications with ships. For example, Portishead Radio, which was the world's busiest radiotelephony station, provided HF long-range, MF medium-range, and VHF short-range services; in 1974, it had 154 radio operators who handled over 20 million words per year. Such large radiotelephony stations employed large numbers of people and were expensive to operate. By the end of the 1980s, satellite services had started to take an increasingly large share of the market for ship-to-shore communications.
For these reasons, the International Maritime Organization (IMO), a United Nations agency specializing in safety of shipping and preventing ships from polluting the seas, began looking at ways of improving maritime distress and safety communications. In 1979, a group of experts drafted the International Convention on Maritime Search and Rescue, which called for development of a global search and rescue plan. This group also passed a resolution calling for development by IMO of a Global Maritime Distress and Safety System (GMDSS) to provide the communication support needed to implement the search and rescue plan. This new system, which the world's maritime nations are implementing, is based upon a combination of satellite and terrestrial radio services, and has changed international distress communications from being primarily ship-to-ship based to ship-to-shore (Rescue Coordination Center) based. It spelled the end of Morse code communications for all but a few users, such as amateur radio operators. The GMDSS provides for automatic distress alerting and locating in cases where a radio operator doesn't have time to send an SOS or MAYDAY call, and, for the first time, requires ships to receive broadcasts of maritime safety information which could prevent a distress from happening in the first place. In 1988, IMO amended the Safety of Life at Sea (SOLAS) Convention, requiring ships subject to it fit GMDSS equipment. Such ships were required to carry NAVTEX and satellite EPIRBs by 1 August 1993, and had to fit all other GMDSS equipment by 1 February 1999. US ships were allowed to fit GMDSS in lieu of Morse telegraphy equipment by the Telecommunications Act of 1996.

 Licensing of Operators

In the United States four different certificates are issued. A GMDSS Radio Maintainer's License allows a person to maintain, install,and repair GMDSS equipment at sea. A GMDSS Radio Operator's License is necessary for a person to use required GMDSS equipment. The holder of both certificates can be issued one GMDSS Radio Operator/Maintainer License. Finally, the GMDSS Restricted License is available for VHF operations only within 20 nautical miles (37 km) of the coast. To obtain any of these licenses a person must be a U.S. citizen or otherwise eligible for work in the country, be able to communicate in English, and take written examinations approved by the Federal Communications Commission. Like the amateur radio examinations, these are given by private, FCC-approved groups. These are generally not the same agencies who administer the ham tests. Written test elements 1 and 7 are required for the Operator license, and elements 1 and 7R for the Restricted Operator. For the Maintainer examination element 9 must be passed. However, to obtain this certificate an applicant must also hold a General radiotelephone operator license (GROL), which requires passing commercial written exam elements 1 and 3. Upon the further passing of optional element 8 the ship radar endorsement will then be added to both the GROL and Maintainer licenses. It should be noted that to actually serve as an operator on most commercial vessels the United States Coast Guard requires additional classroom training and practical experience.

 Learning tools

Many tools exist for teaching GMDSS skills, including various types of simulator. Simulators are very useful because sending false distress communications on live equipment is unsafe and illegal. A good simulator should faithfully reproduce conditions under which GMDSS systems would actually be used at sea. All of the questions and answers asked on the written tests are also available in commercially prepared books.

MARINESHELF publishes articles contributed by seafarers and other marine related sites solely for the benefit of seafarers .All copyright materials are owned by its respective authors or publishers.

Basic Concepts of the GMDSS Functional requirements The GMDSS regulations (chapter IV of the International SOLAS Convention), require that every GMDSS equipped ship shall be capable of; transmitting ship-to-shore Distress Alerts by at least two separate and independent means, each using a different radio communication service; receiving shore-to-ship Distress Alerts; transmitting and receiving ship-to-ship Distress Alerts; transmitting and receiving search and rescue co-ordinating communications; transmitting and receiving on-scene communications; transmitting and receiving locating signals; receiving maritime safety information; transmitting and receiving general radiocommunications relating to the management and operation of the vessel; transmitting and receiving bridge-to-bridge communications.

Application The GMDSS applies to vessels subject to the SOLAS Convention - that is: Commercial vessels of 300 Gross Registered Tons (GRT) and above, engaged on international voyages. The GMDSS became mandatory for such vessels as at February 1, 1999. Commercial vessels under 300 GRT, or those above 300 GRT engaged on domestic voyages only are subject to the requirements of their Flag State. Some Flag States have incorporated GMDSS requirements into their domestic marine radio legislation - however many have not.

Equipment vs Operational requirements The major difference between the GMDSS and its predecessor systems is that the radio communications equipment to be fitted to a GMDSS ship is determined by the ship's area of operation, rather than by its size. Because the various radio systems used in the GMDSS have different limitations with regards to range and services provided, the new system divides the world's oceans into 4 areas: Area A1 lies within range of shore-based VHF coast stations (20 to 30 nautical miles); Area A2 lies within range of shore based MF coast stations (excluding A1 areas) (approximately 100 - 150 nautical miles); Area A3 lies within the coverage area of Inmarsat communications satellites (excluding A1 and A2 areas - approximately latitude 70 degrees north to latitude 70 degrees south); and Area A4 comprises the remaining sea areas outside areas A1, A2 and A3 (the polar regions). Australia and its surrounding SAR area are declared as Sea Area A3. There are no A1 or A2 areas in Aust GMDSS communication systems The GMDSS utilises both satellite and terrestrial (ie: conventional) radio systems. Sea Area A1 requires short range radio services - VHF is used to provide voice and automated distress alerting via Digital Selective Calling (DSC). Sea Area A2 requires medium range services - Medium Frequencies (MF - 2 MHz) are used for voice and DSC. Sea Areas A3 and A4 require long range alerting - High Frequencies (HF - 3 to 30 MHz) are used for voice, DSC and Narrow Band Direct Printing (NBDP - aka radio telex). Equipment requirements vary according to the area the ship is trading to or through. Accordingly, it is quite possible that a small 300 ton cargo vessel may carry the same amount of communications equipment as a 300,000 ton oil tanker, if they are both operating in the same area....this is a marked change from the pre-GMDSS systems. Equipment requirements As discussed above, equipment fit requirements vary according to the Sea Area(s) a vessel operates in or through. It should be noted that the requirements are cumulative in nature - ie: an A4 vessel is also equipped, by definition, with equipment for A1, A2 and A3 Sea Areas. In areas where A1 Services are provided, coastal vessels are only required to fit VHF equipment, provided of course that they remain within the declared Sea Area - normally within 20 to 30 nautical miles of the coast. Vessels that trade further from land are required to carry MF equipment, in addition to VHF. Ocean going vessels fit VHF, MF, HF and Inmarsat equipment.

MARINESHELF publishes articles contributed by seafarers and other marine related sites solely for the benefit of seafarers .All copyright materials are owned by its respective authors or publisher

 

DANGER OF BACKFIRE AND FLASH

BACK OF AUX BOILER

UNBURNT HYDROCARBON GASES PRESENT INSIDE THE FURNACE OF THE BOILER HAS TO BE PURGED OUT BEFORE ATTEMPTING TO IGNITE THE BURNER.

ACCUMULATION OF HYDROCARBON GASES CAN OCCUR DUE TO FOLLOWING REASONS:

1)      FREQUENT ATTEMPTS TO IGNITE BURNER WITHOUT ASCERTAINING AND RECTIFYING CAUSES OF MISIGNITION/MISFIRE.

2)      LEAKY STOP SOLENOID V/VS.

3)      IMPROPER FUEL ATOMISATION LEADING TO IMPINGEMENT AND ACCUMULATION OF FUEL.

4)      OBSTRUCTIONS IN THE UPTAKE CAUSING THE PURGING TO BE INEFFECTIVE.

5)      MALFUNCTIONING OF THE AIR DAMPER CAUSING INSUFFICIENT AIR SUPPLY FOR PURGING.      

ANY ATTEMPT TO IGNITE THE BURNER WHEN THE FURNACE HAS HYDROCARBON GAS ACCUMULATION CAN CAUSE VIOLENT EXPLOSION, BACKFIRE AND FLASH BACK FROM THE FURNACE.  BACK FIRE CAN CAUSE SERIOUS INJURY TO OPERATING PERSONAL AND VESSEL’S EQUIPMENTS.    

STRICTLY FOLLOW THESE INSTRUCTIONS DURING BOILER OPERATION:

      ONLY QUALIFIED ENGINEERS SHOULD OPERATE THE BOILER

       IF THE IGNITION FAILS FOR 5 SECONDS, RELEASE THE MANUAL IGNITION SWITCH IMMEDIATELY, ALLOW FOR POST PURGE AND INVESTIGATE THE CAUSE OF FAILURE.

      DO NOT TRY FOR ANOTHER ATTEMPT WITHOUT CARRYING OUT POST PURGE/PRE PURGING OPERATION.

      ALWAYS STAND ON THE SIDE OF THE BURNER ASSEMBLY WHILE FIRING THE BOILER MANUALLY.

      ANY ABNORMAL ALARM DURING ‘AUTO’ OPERATION SHOULD BE RESET ONLY AFTER INVESTIGATING AND RECTIFYING THE DEFECT.

DURING MAINTENANCE, ALWAYS USE PERSONAL PROTECTIVE AIDS. (COTTON COVERALLS, GOGGLES, FACE SHIELD, FIRE PROOF HAND GLOVES).