4 GMDSS RADIO EQUIPMENT

4.1 Location of VHF transceivers and VHF DSC controllers

.1 VHF with DSC forming part of the mandatory VHF communication equipment for safety of navigation should be located in the conning position. This equipment may be connected to several remote control units, i.e. on the wings of the navigation bridge, provided that the navigating bridge has priority. If such "combined" equipment is chosen, it should be possible to transmit DSC distress alert from the conning position.
.2 If the ship is equipped with extra VHF transceiver (without DSC) with channels required for navigational safety, located in the conning position, another central location of the mandatory DSC VHF equipment on the navigation bridge (in navigating position) can be accepted.

(SOLAS 1974, as amended, regulations IV/4.1.5, 4.1.9 and 6.3.)

Note: - With regard to the location of equipment and distress alerts, the same requirements also apply to the duplicated DSC VHF equipment for ships in sea areas A3 and A4. The duplicated VHF transceiver can, however, be located in the "navigating position" instead of in the conning position.

(IMO resolution A.702(17), Annex, item 2.1.)

In order to conduct power measurements, easy access to the antenna output of each equipment should be provided.

(SOLAS 1974, as amended, regulation IV/15.2 and IMO resolution A.948(23))

4.2 Continuous watch on DSC VHF channel 70

Continuous watch on DSC VHF channel 70 can be met by:

.1 a separate VHF channel 70 watch receiver. It should not be muted or interrupted when using other radio equipment, or
.2 a dedicated watch receiver combined with the VHF transceiver. It should be installed so as to maintain watch even when the VHF equipment is used for telephony, or
.3 VHF with DSC permanently locked on channel 70 for reception and transmission of DSC calls only. To deal with other correspondence on other channels, an additional VHF transceiver should be installed, which may be without the DSC function.

(IMO resolutions A.694(17) and A.803(19), as amended, and COM/Circ.105)

4.3 Location of MF/HF transceivers

.1 If the equipment is main or duplicated equipment, it should be possible to activate the distress alert from the navigation bridge. If the equipment can be remote operated from other positions on board the ship, priority should be given to the unit on the navigation bridge.
.2 With regard to a MF installation, the requirement for DSC distress alerts on 2187,5 kHz can also be fulfilled by a remote-activated MF control unit locked on 2187,5 kHz with alert activated from the navigation bridge.

Note: - DSC on MF is required in sea areas A2, A3 and A4, irrespective of selected radio equipment solution. It should therefore always be possible to activate the DSC distress alerts on 2187,5 kHz from the navigation bridge.

If combined MF/HF radio equipment is chosen as mandatory GMDSS equipment, it should also be possible to activate the distress alert from the navigating bridge on the mandatory HF DSC frequencies.

If MF/HF installation is chosen as duplicated equipment (Inmarsat option) on a ship for sea area A3, there is no requirement for an extra DSC watch receiver.

(SOLAS 1974, as amended, regulations IV/9.2, 10.3 and COM/Circ.105)

.3 RF power amplifiers should, as a general rule, not be located in the navigation bridge area. Location in such area may, however, be accepted if it can be granted that the EMC requirements are fulfilled. The antenna tuner should, as a general rule, be located in an outdoor position below and close to the antenna.

(IMO resolution A. 813(19))

.4 The MF or MF/HF transmitter should be equipped with an instrument or other provisions indicating antenna current or power delivered to the antenna.

(IMO resolutions A.804(19) and A.806(19), Annex, paragraph 6.1, as amended)

.5 If the transmitter antenna is not permanently connected to the transmitter, it should be automatically connected before the distress alert is transmitted.

4.4 Watchkeeping receivers for DSC

.1 Depending on the trade area and mandatory radio equipment of the ship, continuous watch is required via separate receivers for DSC channel 70, MF DSC 2187.5kHz and HF DSC 8414.5 kHz, as well as minimum one of the frequencies 4207.5 kHz, 6312 kHz, 12577 kHz and 16804.5 kHz.

(SOLAS 1974, as amended, regulation IV/12)

.2 The watch receiver for VHF DSC channel 70, MF DSC 2187.5 kHz and HF DSC scanning receiver should be located so that the alarm is clearly audible and visible all over the navigation bridge.

(IMO resolution A.804(19), as amended, and COM/Circ.105)

.3 It should be possible to read the DSC alert messages on the navigation bridge. The printer (if any) or display etc. may be common for all DSC watch receivers, provided that messages coming in simultaneously are arranged in queue and printed as soon as the printer/display is ready.

(IMO resolutions A.803(19), A.804(19) and A.806(19), as amended)

.4 Easy access to the antenna connector should be possible in order to conduct test of the equipment by means of measuring instruments.

Note: - There is no requirement for a duplicated MF/HF DSC watch receiver for ships in sea areas A3 or A4 when maintenance method "duplication of equipment" is used.

(IMO resolution A.702(17), Annex, item 2.1)

4.5 Watchkeeping on MF or MF/HF DSC

4.5.1 Continuous watch on the MF DSC distress frequency 2187.5 kHz to be kept by:

.1 a separate DSC watch receiver locked on 2187.5 kHz; or
.2 a dedicated watch receiver combined with the MF radiotelephone.

Note: - If DSC operation is desirable on other frequencies, an additional scanning receiver should be provided. Other frequencies than those used for distress and safety should not be included in the receiver dedicated for DSC emergency watchkeeping. A single DSC decoder may be used to serve both the DSC watch and the additional scanning receiver.

(COM/Circ.105)

4.5.2 Continuous watch on MF/HF DSC distress and safety frequencies to be kept by:

.1 a separate MF/HF DSC scanning receiver for distress and safety frequencies only; or
.2 a dedicated MF/HF DSC scanning watch receiver for distress and safety frequencies only combined with the MF/HF radiotelephone.

(COM/Circ.105)

Note: - If DSC operation is desirable on other frequencies, an additional scanning receiver should be provided. The receiver may be combined with the watch receiver for MF DSC. A single DSC decoder may be used to serve both the DSC distress and safety frequency scanning receiver and the additional scanning receiver only if continuous watch for distress and safety calls can be maintained.

(SOLAS 1974, as amended, regulations IV/2.1.2, 10.2.2, 12.1.3 and COM/Circ.105)

4.5.3 Watchkeeping on DSC calling frequencies

.1 For watchkeeping on other frequencies than distress and safety frequencies (national and international DSC calling frequencies), a separate scanning receiver should be provided.

Note: - According to SOLAS regulation IV/4.1.8, there is a general requirement for transmitting and receiving "General radio communications". Ships in sea areas A2 should, according to this requirement and according to SOLAS regulation IV/9.3, be able to transmit and receive general radiocommunications on MF or MF/HF telephony or NBDP or Inmarsat ship earth station. Ships in sea area A2, which is equipped in accordance with the minimum SOLAS requirements (i.e. VHF and MF with DSC), should be provided with equipment for listening and calling on national and international MF DSC calling frequencies. Alternatively, they may be provided with Inmarsat equipment in order to fulfil the "general" and "public" correspondence requirements.

According to IMO‘s performance standards, resolutions A.804(19) and A.806(19), as amended, it is required that the DSC equipment should have possibilities as to be used also for "public correspondence". For ships in sea areas A3 and A4 the installed equipment (MF/HF or Inmarsat, depending on installation solution) should also be used for common radiocommunications. In these sea areas the requirements for "general" or "public correspondence" are normally fulfilled either by using the HF or Inmarsat equipment.

(SOLAS 1974, as amended, regulations IV/10 and 11)

4.6 Satellite ship earth station (SES)

.1 If the equipment is the main station or duplicated equipment, it should be possible to activate the distress alert from the navigation bridge.

(SOLAS 1974, as amended, regulation IV/10.3)

.2 The terminal and telephone, if any, may be placed in a "radio workstation" in connection with the navigation bridge or in a separate communication office.
.3 The satellite terminal and/or external printers may also be located elsewhere in the ship.

Note: - Attention should be made to IMO resolution A.807(19), as amended, Annex, paragraph 3.2 regarding Inmarsat-C, which has the following text:

"It should be possible to initiate and make distress calls from the position from which the ship is normally navigated and from at least one other position designated for distress alerting".

The words "one other position designated for distress alerting" is only actual for ships which have defined an additional place/room on board to be such "other position". Normally it will be accepted that Inmarsat-C equipment is installed in the "radio work station" if it is provided with facilities for conducting distress alerts from the navigation bridge. It is, however, recommended that the Inmarsat-C terminal, including additional equipment, should be located on the navigation bridge in order to make it possible to conduct follow-up distress communication from this position.

4.7 Connection of external located data terminal to mandatory Inmarsat-C ship earth station in the GMDSS

If the licensee/shipowner wants to connect the mandatory Inmarsat-C terminal i.e. to the ship's PC-network or to an outside located data terminal, all mandatory GMDSS requirements in accordance with SOLAS 1974, as amended, should always be fulfilled.

In that case, the dedicated printer should be connected permanently to the output of the mandatory Inmarsat terminal's printer output. A manually operated and duly marked switch, located near the Inmarsat terminal, should be installed to disconnect the Inmarsat terminal from the external equipment.

4.8 Extra requirements for passenger ships

.1 A distress panel should be installed at the conning position, i.e. within the range of the manoeuvring consol in the front of the navigation bridge.
.2 This panel should contain either one single button which, when pressed, indicates a distress alert using all radiocommunication installation required on board for that purpose; or
.3 One button for each individual radio installation which are installed.
.4 The distress alert panel should clearly and visually indicate whenever any button or buttons have been pressed. Means should be provided to prevent inadvertent activation of the button or buttons.

Note: - The alert button or buttons should be protected against inadvertent activation by use of a spring loaded lid or cover permanently attached by e.g. hinges in order to fulfil the requirement of carrying out "at least two independent actions" when transmitting distress alert; IMO requirements in force from 23 November 1996. (The button or buttons should be pressed for at least 3 seconds before the alarm is activated.)

.5 If the installed satellite EPIRB is used as the secondary (mandatory) means of distress alerting and is not remotely activated, it should be acceptable to have an additional EPIRB (406 MHz or Inmarsat-E float-free or manual) installed on the navigation bridge near the conning position.
.6 Information on the ship's position should be continuously and automatically provided to all relevant radiocommunication equipment to be included in the initial distress alert when the button or buttons on the distress panel is pressed (i.e. interface connection from the ship's GNSS receiver should be provided, where GNSS is not integrated).

(SOLAS 1974, as amended, regulation IV/6.4)

.7 The distress alert panel is normally included in the distress panel and should provide visual and aural indication of any distress alert or alerts received on board and should also indicate through which radiocommunication service the distress alerts have been received.

(SOLAS 1974, as amended, regulation IV/6.6)

Note: - The following guidelines (table) should apply with regards to the connection of equipment to the distress panel in order to fulfil the IMO requirements concerning ship-to shore distress alerts by at least two separate and independent means:

Sea areas		Equipment
A1		VHF DSC, VHF DSC EPIRB or satellite EPIRB
A1+A2		VHF DSC, MF DSC, satellite EPIRB
A1+A2+A3	(alternative 1)	VHF DSC, MF DSC, Inmarsat, satellite EPIRB
A1+A2+A3	(alternative 2)	VHF DSC, MF/HF DSC, satellite EPIRB
A1+A2+A3+A4		VHF DSC, MF/HF DSC, Inmarsat, satellite EPIRB

Note: - Only radio equipment according to SOLAS 1974, as amended, chapter IV are required to be connected to this distress panel to fulfil the requirement for ship-to-shore distress alerts by means of at least two separate and independent means. The duplicated equipment, as required by IMO resolution A.702(17) for ships in sea areas A3 and A4, are, therefore, in general, not required to be connected to the distress panel if it is granted that distress alert can be transmitted from the duplicated equipment in a position close to the installed distress panel.

4.9 NAVTEX and EGC (Enhanced Group Call) receiver

.1 The printer for NAVTEX and Inmarsat EGC receiver should be located on the navigation bridge. As mandatory equipment in the GMDSS, these receivers should also, as a general rule and in the same way as required for other permanent installed equipment, have their own permanent installed power supplies with fuse circuits/fuses, cf. subsection 7.19. Antenna and antenna cable should also be permanently installed.
.2 The mandatory requirement for an EGC receiver may be combined with Inmarsat equipment. It is recommended that a dedicated EGC receiver is used, enabling continuous reception of MSI (Maritime Safety Information) messages independent of whether the Inmarsat equipment is being used or not. "Class 3 EGC" is included in the Inmarsat-C, but only shares the antenna with this equipment and functions in parallel with and separate of the Inmarsat-C equipment.

(SOLAS 1974, as amended, regulations IV/7.1.4 and 7.1.5 and IMO resolution A.701(17))

4.10 Satellite float-free EPIRB

The satellite float-free EPIRB should be located/installed so that the following requirements are fulfilled:

.1 The EPIRB should, with greatest possible probability, float-free and avoid being caught in railings, superstructure, etc., if the ship sinks.
.2 The EPIRB should be located so that it may be easily released manually and brought to the survival craft by one person. It should therefore not be located in a radar mast or any other places which can only be reached by vertical ladder.

(SOLAS 1974, as amended, regulations IV/7.1.6, 8.1.5.2, 9.1.3.1, 10.1.4.1, 10.2.3.1 and IMO resolutions A.763(18), A.810(19), as amended, and A.812(19))

Note: - A float-free EPIRB may also be used to fulfil the requirements for one piece of equipment (of two), which is capable of transmitting distress alert to shore from or near the navigating bridge of the ship. Under such conditions the float-free EPIRB should fulfil the following additional requirements with regards to location/installation:

.3 The EPIRB must be installed in the vicinity of the navigation bridge, i.e. on the wings of the navigation bridge. Access via vertical ladder should not be accepted. A location on the top of the wheelhouse may be accepted to fulfil the requirement if accessible by stairs; or

(SOLAS 1974, as amended, regulation IV/7 and COM/Circ.105)

.4 It may be possible to activate the EPIRB remotely from the bridge. If remote activation is used, the EPIRB should be installed so that it has unobstructed hemispherical line of sight to the satellites.

(COM/Circ.105)

Note: - It should be considered that the main function of the EPIRB is float-free activation. If the additional requirements mentioned above cannot be met without reducing the reliability of the float-free activation, priority should be given to this requirement. Alternatively, two float-free EPIRBs should be installed.

.5 The EPIRB should be equipped with a buoyant lanyard suitable for use as a tether to life raft etc. Such buoyant lanyard should be so arranged as to prevent its being trapped in the ship's structure.

(IMO resolutions A.810(19) and A.812 (19), as amended)

.6 The EPIRB should be marked with the ship's call sign, serial number of EPIRB, MMSI number (if applicable),15 Hex ID, and battery expiry date.

4.11 Search and rescue radar transponders (SART)

.1 The search and rescue radar transponders should be placed in brackets on both sides of the ship and preferably visible from the navigation bridge. It should be easy to bring the transponders to the lifeboats or life-rafts. A visible location inside the navigation bridge, close to the outer doors, is recommended.

Alternatively one radar transponder should be placed in bracket in each survival craft (normally covered lifeboats) if such location permits rapidly replacing of the SARTs into any survival crafts which may be used in emergency situations.

The SART should be provided with a pole or other arrangement compatible with the antenna pocket in the survival craft in order to fulfil the required height of at least 1 metre above sea level.
.2 On ships carrying at least two radar transponders and equipped with free-fall lifeboats one of the radar transponders should be stowed in a free-fall lifeboat and the other located in the immediate vicinity of the navigation bridge so it can be utilized on board and ready for transfer to any of the other survival craft.

(SOLAS 1974, as amended, regulation III/6.2.2 and IMO resolution A.802(19))

.3 The SARTs should have waterproof marking with operational instructions, battery expiry date and the ship's name and call sign.

4.12 Hand held (Two-way) GMDSS VHF transceivers

.1 Obligatory hand-held VHF transceivers including their emergency batteries (primary batteries normally of Lithium type) should be located in a central and easily accessible position on the navigation bridge. If such equipment is placed in a lockable cabinet, it should be possible to get easy access to the hand-held VHF transceivers without the use of tools.
.2 Primary batteries should be sealed for use only in emergency situations and marked by the supplier with battery expiry date. The battery will be considered as exhausted and used if its seal is broken, and a new battery will be requested during radio survey, cf. the IMO requirement for 8-hours operation in emergency situations.
.3 If hand-held VHF with re-chargeable NiCd batteries (secondary batteries) are used for on-board communications, chargers for these batteries should be provided.

(SOLAS 1974, as amended, regulation III/6.2.1 and IMO resolutions A.762(18), A.809(19) and MSC.149(77))

.4 Hand-held VHF transceivers should have waterproof marking with the ship's name and call sign. The primary battery should be marked with expire date. Channel numbers should be stated on the equipment.

4.13 Hand-held VHF transceivers and communications from the wings of the navigation bridge

Requirements for radiocommunications from the wings of the navigation bridge are laid down in the SOLAS Convention. In order to fulfil this requirement, mandatory hand-held GMDSS VHF can be used. (see subsection 4.10). Alternatively a simplex VHF transceiver (single frequency only) or remote controlled units with channel selector, loudspeaker and microphone may be installed in these positions. These remote controlled units should be controlled by a VHF installed in the front of the navigation bridge.

(SOLAS 1974, as amended, regulation IV/6.3 and COM/Circ.105)

4.14 Aeronautical mobile emergency radiocommunication equipment

.1 All passenger ships should be provided with means for two-way on-scene radiocommunications for search and rescue purposes using the aeronautical frequencies 121.5 MHz and 123.1 MHz from the navigation bridge.

Such equipment should be marked with the ships name and call sign. The primary battery should be marked with expiry date.

(SOLAS 1974, as amended, regulation IV/7.2)

.2 Approved equipment may be of a fixed type or a hand-held type. The equipment should be provided with the frequencies 121.5 MHz and 123.1 MHz only.

(IMO resolution MSC.80(70))

4.15 GNSS – global navigational satellite system

.1 In passenger ships irrespective of size, information on the ship's position should be continuously and automatically provided to all relevant radiocommunication equipment. With such connections the ship's position will be included in the initial distress alerts.

(SOLAS 1974, as amended, regulations IV/6.5 and V/19)

.2 In cargo ships, where GNSS should be installed in accordance with new regulation V/19, automatic updating of the ship's position into the DSC equipment and Inmarsat equipment should be possible. If such automatic updating is not possible, it is required to enter the ship's position manually into relevant GMDSS equipment at intervals not exceeding 4 hours whenever the ship is under way.

(SOLAS 1974, as amended, regulation IV/18)

If the GNSS is connected to the GMDSS equipment, it should (similar to the mandatory GMDSS equipment) be supplied with energy from the reserve source of energy/batteries.

(SOLAS 1974, as amended, regulation IV/13.8)

4.16 Connections of navigational sensors

4.16.1 GNSS - Receiver

A GNSS receiver should be connected to the relevant radio communication equipment (DSC controller, GMDSS satellite equipment) in order to provide information on the ship's position continuously and automatically to the radio equipment.

The GNSS receiver should (similar to the mandatory GMDSS equipment) also be supplied with energy from the reserve source of energy/batteries.

4.16.2 Heading sensor

If the GMDSS satellite equipment requires automatic antenna adjustment according to ship's heading, the heading sensor (GYRO) should be connected.

In this case the GYRO should also be supplied with energy from the reserve source of energy/batteries.