Annex 20 - Inspection and Survey of Navigational Equipment
These notes cover the survey and inspection of the equipment required to be carried under SOLAS V/19 and V/20 and replace “Merchant Shipping Navigational Equipment – Instructions for the Guidance of Surveyors.”



1.1 Object of the guidance notes
1.2 Statutory Provisions
1.3 Exemption
1.4 Report of inspection
1.5 Procedure when an installation is found to be deficient or defective
1.6 Procedure when an installation is not provided
1.7 Fees
1.8 Safety during inspections
1.9 Navigational Equipment Standards
1.10 Power supplies
1.11 Documents
1.12 Tools, measuring instruments, spare parts etc.
1.13 Maintenance


2.1 Preparatory work
2.2 Checks to be made
2.3 Operational tests
2.4 Completion of inspection


3.1 Submission of plans
3.2 Equipment precautions

3.2.2 Electromagnetic Compatability (EMC)
3.2.3 Protection of magnetic compasses
3.2.4 Interference
3.2.5 Acoustic noise
3.2.6 Heat and/or fumes
3.2.7 Vibration
3.2.8 Look out and Night Vision

3.3 Accident prevention


4.1 Siting of the transducer
4.2 Siting of displays


5.1 Magnetic compass standards
5.2 Siting of magnetic compasses

5.2.1 Siting of the Standard compass
5.2.2 Siting of compasses in Small Ships on Restricted Service
5.2.3 Heading information at Emergency Steering Positions

5.3 Non-Dependence on electrical power
5.4 Adjusting compasses
5.5 Records
5.6 Operational checks


6.1 Siting of gyro compass units
6.2 Operational checks



8.1 Siting of the antenna unit
8.2 Display units
8.3 Waveguide and cable runs – installation and inspections
8.4 Operational checks
8.5 Measurement of Shadow Sectors
8.6 Radar plotting aids


9.1 General
9.2 Siting







1.1) Object of the Guidance Notes

    1.1.1) These notes are primarily for the guidance of Surveyors inspecting navigational equipment installations for the purposes of the Merchant Shipping (Safety of Navigation) Regulations 2002, referred to as the "Regulations", which implement the revised Chapter V of the International Convention for the Safety of Life at Sea (SOLAS 74/78). They also indicate to owners, masters and crews, shipbuilders and installation companies the requirements which certain vessels should meet in order to comply with the Regulations.

    1.1.2) Carriage requirements for navigational equipment are contained in SOLAS V Regulations 19 and 20 and references to the appropriate paragraphs of the Regulation are given in the text of these notes in the form “SOLAS V/19.2.4”

    A table of Navigation Equipment requirements under Regulation V/19 and V/20 is provided in ANNEX 11 - Navigational equipment - New ships

    1.1.3) Provisions for “Existing” Ships: SOLAS V/19.1.2 allows ships constructed before 1 July 2002 to continue to comply with the SOLAS V Regulations in force before that date (SOLAS V/11, V/12 and V/20 of the old Chapter) if they do not fully comply with the requirements of SOLAS V/19, with three exceptions:

    a) Global Navigation Satellite System Receiver (GNSS) (SOLAS V/ must be fitted not later than the first survey after 1 July 2002 and

    b) Automatic Identification System (AIS) (SOLAS V/19.2.4) not later than the dates laid down in that Regulation. (See also ANNEX 17)

    c) Voyage Data Recorders (VDRs) or Simplified Voyage Data Recorders (S-VDRs) (SOLAS V/20 are required to be fitted in accordance with the timetable in SOLAS V/20.

    Full details for VDR / S-VDR carriage requirements and survey and checking arrangements are set out in ANNEX 10.

    ANNEX 12 – Navigational Equipment – Existing ships contains a table of equipment requirements and the relevant text of SOLAS V in force prior to 1 July 2002. (SOLAS V/74)

1.2) Statutory provisions

The principal statutory provisions covering navigational equipment requirements for merchant vessels are contained in:

The Merchant Shipping Act 1979
The Merchant Shipping Act 1995
The Merchant Shipping (Safety of Navigation) Regulations 2002
The Merchant Shipping (Survey and Certification) Regulations 1995
The Wireless Telegraphy Act 1949
The Wireless Telegraphy Act 1967
The Merchant Shipping (Radio Installation) Regulation 1998
Chapter V, International Convention for the Safety of life at Sea (SOLAS V)

1.3) Exemption

1.3.1) The MCA is empowered to exempt any vessel from any of the requirements of the Regulations. (See SOLAS V/3) Applications for exemption should be sent by the owners or their representative to the surveyor in charge of the local Marine Survey Office of the MCA. Any such application should contain detailed reasons why a statutory requirement is considered to be impracticable or unreasonable. A copy of any exemption granted by the MCA should be retained on board with the ship's documents.

1.3.2) The Secretary of State may grant to individual ships or classes of ship partial or conditional exemptions when engaged on certain voyages. When deciding whether to grant exemptions due account will be taken of the effect that an exemption may have on the safety of other ships. Specifically, deferments in the application of specific regulations may be granted to individual ships where structural alterations are necessary to install equipment required by the regulations. Exemptions are granted for a specific period only, normally associated with the Safety Certificate.

1.4) Report of inspection

When the inspection has been completed the Surveyor should issue a Form MSF 1102. It is advised that this form should be retained on board with the ship's papers.

1.5) Procedure when an installation is found to be deficient or defective

1.5.1) Where a Surveyor considers an installation is deficient or defective, details are to be recorded on Form MSF 1603 together with the action required.

1.5.2) It is emphasised that the Master, owner or his representative should make every effort at all times to have any deficiencies or defects corrected. A Surveyor finding significant defects affecting the safe operating of the ship and in breach of the regulations should consider notifying the enforcement unit of the MCA.

1.5.3) Refer to SOLAS V/16.2 Maintenance of Equipment and the relevant MCA Guidance Notes which relate to the detention of ships when equipment is non-operational or malfunctioning.

1.6) Procedure when an installation is not provided

When a Surveyor finds that mandatory equipment is not provided he should contact the Principal Surveyor or the Surveyor in Charge, as appropriate, for a decision on whether detention is appropriate.

1.7) Fees

The fees for inspection of navigational equipment installations, either during construction or subsequently on board ship, are contained in the current Merchant Shipping (Fees) Regulations.

1.8) Safety during inspections

To ensure that the equipment is not inadvertently damaged, or ships' personnel placed at risk during inspections, a responsible person representing the owners and capable of operating the equipment, should be present when Surveyors make their inspection. If the owner is not so represented the Surveyor should not proceed with the inspection unless he is satisfied that it is safe to do so and has the agreement of the Master or representative of the shipowner.

1.9) Navigational Equipment Standards

1.9.1) Navigational equipment installations fitted in compliance with the Regulations are required to conform to the relevant performance standards adopted by the International Maritime Organization (IMO) and, if fitted to United Kingdom (UK) ships, with relevant performance specifications. Further details on Performance Standards are contained in ANNEX 8 and ANNEX 9.
The standards adopted by IMO and performance specifications for navigational equipment to be fitted to United Kingdom ships are specified in MSN 1734 (M+F) & MSN 1734 (amnd), and MSN 1735 (M+F) & MSN 1735 (amnd)
Refer also to SOLAS V/18 "Approval, Surveys and Performance Standards of navigational systems and equipment and Voyage Data Recorder" and the related MCA Guidance Notes.
See also
ANNEX 8 – Guidance Notes on Performance Standards and Type Approval, and
ANNEX 9 – Table of IMO Performance Standards and associated testing standards

1.10) Power supplies

1.10.1) The Surveyor should ensure that a source of electrical energy suitable and sufficient for the operation of the installations required by the Regulations or for the purpose of testing and charging any batteries which are a source of electrical energy for any part of the installations, is provided. The source of electrical energy should be available at all times while the ship is at sea and at all reasonable times when it is in port. The Surveyor should be satisfied that the limits of electrical energy specified in the Regulations are not likely to be exceeded under normal conditions, and that adequate means are provided for disconnecting the supply of electrical energy from each installation. Where an emergency source of electrical energy is provided and the Regulations require that two radar installations should be provided, while both radars should be capable of being run from the emergency source of electrical energy, the arrangements may be such that only one radar at a time need be connected to the emergency source.

1.10.2) Electrical equipment and installations should be such that the ship and all persons on board are protected against electrical hazards, and should, where applicable, conform with the provisions of Regulations for the Electrical Equipment for Ships issued by the Institution of Electrical Engineers.

1.11) Documents

A ship required by the Regulations to be fitted with navigational equipment installations should carry the following documents:

a) a report of survey as applicable;

b) a current exemption certificate, where applicable;

c) servicing and operating information in English for each item of navigational equipment; See also ANNEX 7 – IEC Requirements for Equipment manuals.

d) a magnetic compass deviation card(s);

e) records of compass deviations; and

f) a record of the radar shadow sectors.

1.12) Tools, measuring instruments, spare parts etc.

1.12.1) Ships should carry a list of the tools, measuring instruments, spare parts, etc. on board which shipowners consider necessary for compliance with the requirements of SOLAS V/16. The provision of such items should take into account the type of equipment fitted, the tools necessary for carrying out the maintenance, measuring instruments, and the nature of the ships trade.

1.12.2) Surveyors should check the stock against the list provided by the shipowner and request deficiencies to be made up.

1.13) Maintenance

Shipowners should be requested to provide adequate and safe access to all units of navigational equipment so that they can be maintained and adjusted in situ. Particular attention should be given to the problems of maintaining radar antennae.


The checks and tests listed in this section are not exhaustive, but intended only to provide guidance during inspections and should not be interpreted as imposing a limit upon a Surveyor to carry out only those tests and checks shown.

2.1) Preparatory work
2.1.1) Before commencing an inspection, the Surveyor should establish whether:

a) the ship is required to meet the requirements of the revised SOLAS V/19 and V/20 or whether, being an “existing” ship, it is still complying with the appropriate regulations in force prior to 1 July 2002 as allowed under SOLAS V/19.1.2.

b) an exemption from or deferment of any part of the appropriate Regulations is currently in force for the ship and, if so, the conditions imposed by the exemption certificate.

c) it is safe for an inspection to take place before commencing any work (see paragraph 1.8).

2.2) Checks to be made

The following should be checked:

a) The navigational equipment installations required by the Regulations are in place.

b) The siting and fitting of the installations is satisfactory.

c) The proper documents are carried on board the vessel (see paragraph 1.11).

d) The log has been maintained (where applicable).

e) The stock of tools, miscellaneous items, measuring instruments, spare parts, etc. (see paragraph 1.12).

2.3) Operational tests

Surveyors should check that the navigational equipment required by the Regulations is operating satisfactorily in accordance with the manufacturer's handbooks and, where appropriate, with the additional operational checks set out in this Annex.

2.4) Completion of inspection

2.4.1) When the inspection has been completed satisfactorily, the Surveyor will notify the Master, the shipowner or his representative accordingly.

2.4.2) When an installation is found to be deficient or defective, action should be taken in accordance with paragraph 1.5. If, after having taken all the relevant circumstances into consideration, the Surveyor considers that the Regulations are being breached to the extent that a prosecution may be justified, he should inform the Master, the shipowner or his representative and contact the enforcement unit.

2.4.3) When an installation required by the Regulations is not provided, action should be taken in accordance with paragraph 1.6


3.1) Submission of plans

Shipowners and shipbuilders should be advised to forward plans and particulars of the proposed navigational equipment installations in new vessels to the local Marine Office at the design stage. This will provide an early opportunity to determine, as far as possible, whether the proposals comply with the Regulations. In the case of existing ships, shipowners and shipbuilders are advised to notify the local Marine Office of proposed new navigational equipment installations or changes to existing installations at an early stage in the work.

3.2) Equipment precautions

3.2.1) Equipment installed in an exposed position

Equipment should not be installed in an exposed position, or in a position which normally permits the entry of moisture or water into it unless it has been approved for the category “exposed to the weather” (formerly Class X) of standard IEC 60945.

3.2.2) Electromagnetic Compatability (EMC)

All equipment must meet the relevant EMC requirements and Surveyors should refer to SOLAS V/17 Electromagnetic Compatability and the Statutory requirements listed in the related Guidance Notes

3.2.3) Protection of magnetic compasses The siting of electronic navigational installations should, where practicable, ensure that the accuracy of the ship's magnetic compasses is adequately safeguarded. Attention is drawn to the relevant guidance in Section 6. Each unit of type approved equipment is tested to determine the minimum safe distances at which it should be installed from both steering and standard magnetic compasses, in order not to affect the accuracy of these compasses significantly, and such safe distances are indicated on the unit concerned or in its handbook. A safe distance takes account of both the constant effect on a magnetic compass due to the presence of magnetic material and also any variable effect due, for example, to electrical circuits or to opening or closing of drawers or panels. Thus, provided a unit is not placed in a position nearer the centre of the bowl of a magnetic compass than the prescribed safe distance, the unit may be installed or removed without any need for adjustment of that compass. When installing navigational equipment in a particular ship, if it should prove impracticable to site any particular unit of the equipment at a distance from a magnetic compass equal to or greater than the appropriate safe distance, the Surveyor should investigate the effect of such siting on the compass with regard to whether the compass will be stable and errors can be allowed for by compass adjustment. If the equipment fitted is of a type which has not been type approved, the compass safe distances may not be marked on it. Whenever such equipment, other electrical instruments and other apparatus which produces a magnetic field are placed or sited near a magnetic compass, care should be taken to see that they do not affect the compass whether they are energised or not. Normally equipment for which the "safe distance" is not known should be separated from a standard or steering compasses by at least 7 metres. This distance may however be reduced to 5 metres for standard compasses and 3.5 metres for steering compasses in ships of less than 60 metres overall length. Steel fittings with doors, drawers, etc., opening towards any magnetic compass should be so sited that the appropriate separation distances between the compass and any magnetic material are maintained when the doors, drawers, etc. are fully opened.

3.2.4) Interference Whilst direct radio interference from units of type approved equipment should not be excessive, it is advisable that all such units, and particularly those containing the radar modulator, should where practicable be widely separated from radio communication systems. Electrical interference or mechanical noise produced by a navigational installation should not prevent the efficient operation of other equipment installed in the ship. If excessive interference is experienced it is essential that the cause should be determined and steps taken to provide adequate suppression. It is emphasised that the ultimate responsibility for locating and clearing interference is a matter for the owner and that interference which measurably impairs the reception of radio signals, or the performance of other equipment is seldom caused by the equipment on which the interference is noticeable. British Standards BS EN 60945 and BS EN 60533 deal with radio interference on marine installations and lays down permissible limits of interfering voltages and measures to be taken to reduce interference.

3.2.5) Acoustic noise

Care should be taken in siting the units of navigational installations to ensure that noise from them will not interfere with members of the crew when either on or off duty. Guidance on noise levels in various parts of a ship is given in the Code of Practice for Noise Levels in Ships, published by The Stationery Office (TSO).

3.2.6) Heat and/or fumes

Care should be taken to avoid siting equipment in positions where excessive heat and/or fumes may cause failure or undue maintenance difficulties.

3.2.7) Vibration

New installations including antennae should, where practicable, be mounted on a base or platform designed to prevent the performance and reliability of the installation being adversely affected by vibration. In particular in the case of radar installations, they should not be subject to vibrations greater than those specified in British Standard BS EN 60945, General Requirements for Marine Navigational Equipment. If there is evidence to suggest that faults are developing or recurring due to excessive vibration under service conditions the Surveyor should consult with the shipowner.

Where rigidity relies on stays, the Surveyor should ensure these are correctly tensioned.

3.2.8) Lookout and Night Vision

The bridge displays for each item of equipment should be carefully sited so that they do not interfere with the keeping of a proper visual lookout by day or night. Particular attention must be paid to the instrument illumination. It should enable watchkeepers to have optimum information clearly available to them without reducing their night-vision or affecting their ability to maintain a lookout

3.3) Accident prevention

3.3.1) High Voltage Circuits. Type approved equipment should be so designed that there are safeguards which either prevent access to high voltages by means of isolating switches, door switches etc., or ensure that access is only possible by means of a tool such as a key, spanner or screwdriver. Each unit of a non-type approved equipment should be installed so as not to constitute a danger either by physical contact or by electric shock to those who handle it.

3.3.2) RF and X-Radiation present a hazard to personnel. Where such a hazard exists, type approved radar sets are required to have warning notices and instructions in the handbook (in the case of RF radiation) or in the handbook and on a label on the equipment (in the case of X-Radiation), detailing the safe distances. In the case of non-type approved radars precautions should be taken, similar to those required for a type approved set of comparable characteristics.

3.3.3) Antenna units should be sited so as not to constitute a hazard to personnel working near them (see also 1.14 and 8.1).


4.1) Siting of the transducer

4.1.1) One of the most important considerations to be taken into account when installing echo sounder equipment is the selection of the transducer position. The ideal position is one in which the water is free from aeration beneath the transducer, and where the effects of surface, engine and propeller noise are at a minimum. There are, however, few positions in a ship which are suitable in every respect, also a position found to be satisfactory in one design of ship may not necessarily produce equally good results in another.

4.1.2) The principal source of aeration is the bow wave created by a moving ship where aerated water is forced beneath the hull. The resultant bubble stream normally starts about a quarter length of the ship from the stem, and divides about three-quarters of the length from the bow. The bubble stream varies in form and intensity according to the speed, draught, shape of bow and hull, and the trim of the ship as well as the sea state. These factors should be taken into account when siting the transducer. In particular, in the case of a ship with a bulbous bow, the only satisfactory forward site may be within the bulb, although the possibility of physical damage has to be recognised.

4.1.3) To avoid aeration, a position at the forepeak is desirable but it may be unsatisfactory in a ship with a light draught forward, especially in bad weather conditions. In addition, the hull shape may make fitting difficult. In a laden ship of normal design a position within a quarter of the ship's length from the stem will often be found to give satisfactory results. On small ships damage may occur due to pounding and care should be taken when siting the transducer. An aft position may be more suitable than one forward. Care should be taken, however, to site the receiving transducer a sufficient distance from the propellers to avoid the effects of noise or aeration. When separate transmitting and receiving transducers are fitted, they should be sufficiently separated to prevent interaction between them but the separation should be as small as possible to ensure accurate soundings in shallow water. Positions either side of the keel are sometimes found to be satisfactory.

4.1.4) Other factors which should be borne in mind when fitting transducers are as follows: The transducer is best located in a horizontal position. In some cases fitting with a slight projection from the hull will help avoid the effects of aeration at the hull surface. If the transducer projects from the hull it will be necessary to 'fair off' this projection. If, in exceptional circumstances, a windowed transducer has to be used, the window should be acoustically transparent, so that the range of the equipment will not be adversely affected. Siting should be avoided near and particularly aft of obstructions such as a forward propeller, bow thruster, water intake/discharge pipes, drain plugs and external speed measuring devices. To minimise the effects of roll and pitch a position near to the centre line should be chosen when practicable. When appropriate, care should be taken to minimise interference between echo sounders and Doppler speed devices.

4.1.5) Information on transducer location should be kept on board with the equipment handbook.

4.2) Siting of displays

4.2.1) The display should be sited on the bridge in a position to facilitate easy access, viewing and servicing, and where the effect of any lighting necessary for the equipment does not interfere with the keeping of an effective look-out.

5.1) Magnetic compass standards

5.1.1) Every standard magnetic compass installed on a ship should have been individually tested at an authorised testing establishment and certified as complying with the required standards.

5.1.2) Every steering magnetic compass installed on a ship and every compass accessory and binnacle, should be of a type for which a Certificate of Type Approval has been issued.

5.1.3) Every spare magnetic compass carried by a ship should be of a type for which a Certificate of Type Approval has been issued except that where the ship is fitted with a standard compass which is of the transmitting type, the spare compass complete with its own transmitting element, should have been individually tested and certified. In all ships fitted with more than one compass, the compass bowls with their gimbal units should be interchangeable.

5.1.4) The addresses of the two UK authorised testing establishments are given in ANNEX 13. All testing and certification currently carried out is to BS 150 2269 standards.

5.1.5) Under the “Scheme for the Reciprocal Recognition of Tests and Inspections carried out on Ships Equipment”. Certificates of Individual Testing or Type Approval for Magnetic compasses, accessories, binnacles and correcting devices issued by an authorised testing establishment in any of the countries listed below may be regarded as the equivalent of a certificate issued by an MCA Notified Body (NB), provided that the equipment has been Type Approved by one of the NBs within the EU, capable of testing compasses and is certified as complying with ISO 2269 for Class A compass or ISO 10316 for Class B compass.

Participating countries with Notified Bodies able to Type Approve compass and accessories include Denmark, Finland, Iceland, Norway, Portugal, Sweden, United Kingdom, Germany, and France.

5.2) Siting of magnetic compasses

5.2.1) Siting of the Standard compass The standard magnetic compass should, where practicable, be so positioned to maximise its distance from the ship’s magnetic material. While this might be difficult to achieve in respect of the fore end of the bridge or compass deck, the maximum, reasonable, distance should have been achieved e.g. by raising the binnacle on a platform. Any magnetic material which is in the vicinity of the compass should preferably be positioned symmetrically, relative to the compass. In ships of unusual design or special purpose, and some small ships, adequate separation of the magnetic compass from magnetic material may not be practicable. The plans submitted at the design stage (see paragraph 3.1) should include any proposed arrangements, for example, the use of under deck binnacles, and/or the use of non-magnetic materials, intended to minimise the effect of the ship's structure on magnetic compasses. In cases in which the only positions available to site the standard compass are such that, after all reasonable steps have been taken to separate the magnetic compass from magnetic material, significant doubts exist as to the adequacy of the separation, the owner of the ship may be advised that the arrangements will be accepted subject to the performance of the compass in service being reviewed. In order that the review can be made, arrangements should be made for the following information to be supplied to MCA Headquarters:

a) A copy of the deviation card after each adjustment of the compass.

b) Sample deviations over a range of latitudes, courses and dates, extending over a period of six months from the date of the first compass adjustment, sufficient to make an overall assessment of the general performance of the compass.

c) A statement by the Master as to his opinion of the standard compass performance over the six month period described in (b), with comments e.g. whether relevant correctors were adjusted for latitude, etc. Reference should be made to IS0 694R - Positioning of Magnetic Compass in ships.

5.2.2) Siting of Compasses in Small Ships on Restricted Service In ships of less than 60 metres in length, designed for a service in which magnetic latitude will not materially change, distance from the ship’s magnetic material may be reduced.

5.2.3) Heading information at Emergency Steering Positions (See SOLAS V/ An emergency steering position is a place in the steering gear compartment provided to control the steering gear. On ships constructed prior to 1 February 1992 an emergency steering position may be located at a place other than in the steering gear compartment. Heading information at emergency steering positions on ships constructed on or after 1 February 1992 should be provided by means of a gyro or magnetic compass repeater. Heading information at emergency steering positions on ships constructed prior to 1 February 1992 may be provided by a telephone or other means of communication.

5.3) Non-Dependence on electrical power

Where the only magnetic compass fitted to a ship is of the projector, reflector or transmitting type, the compass should be capable of being used as a normal magnetic compass on failure of electric power. (See SOLAS V/

5.4) Adjusting compasses

MCA Guidance on adjusting magnetic compasses is given in ANNEX 13

5.5) Records

All ships should carry a record of deviations, which should be kept up to date and contain the dates of adjustment and re-adjustment of each magnetic compass installed on the ship. Deviations should be ascertained by means independent of the gyro compass. Watchkeepers are advised to check the compass error after each major alteration of course, or at least once per watch where no major alteration has taken place. (See also ANNEX 13)

5.6) Operational checks

5.6.1) The performance of all magnetic compasses, including spares should be checked as follows:

a) Freedom of movement of the gimbal.

b) Card floating freely and level, and rotating without any friction.

c) Liquid free of bubbles and clear.

d) Compass card clear and sharp (able to be read) with no distortion or discoloration.

e) Optical system (if any) correctly adjusted and clean.

f) Azimuth reading devices and means of illumination in working order.

g) No liquid leaks around seals or filler plugs.

5.6.2) The compass deviation records and the deviation card for each magnetic compass installed on the ship should be checked.

(Ref. SOLAS V/ –

6.1) Siting of gyro compass units

6.1.1) The master unit should be installed on a firm horizontal base. It should be as free from vibration as is practicable and have adequate space around the unit for access and ventilation. Adequate ventilation is particularly important for units which incorporate cooling fans.

6.1.2) The fore and aft line of master units, binnacles and repeaters used for taking visual bearings should align with, or be parallel with, the fore and aft axis of the ship and compass cards should be clearly visible so that accurate reading of the ship's heading is readily available.

6.1.3) Where the gyro compass installation provides steering information, the master unit or repeater, as applicable, should be installed adjacent to the conning position located such that the ship's heading can easily be read by the helmsman.

6.1.4) Bridge wing repeaters, where fitted, should be installed in positions which provide the maximum possible unobstructed view of the horizon.

6.2) Operational checks

6.2.1) The compass should, if necessary, be allowed to settle. (Note:- It may be necessary for the surveyor to exercise his judgement if the inspection is carried out on a ship moored alongside a quay or at moorings.)

6.2.2) If the compass is not settled, during the settling period check that all repeaters remain in alignment with the master compass reading.

6.2.3) Check that the datum line on the base of all bearing repeaters is aligned with the fore and aft axis of the ship.

6.2.4) Ascertain the compass error by the best method that is practicable according to the circumstances. The settle point error should not exceed: 0.75 x SECANT LATITUDE (DEGREES)

If the ship is not alongside make allowance for difficulty of measurement and for the allowed error of 0.5° between compass and bearing repeater.

6.2.5) Check that all repeaters used for navigation purposes are aligned to the gyro compass heading to within +/- 0.5°.

6.2.6) The mechanical parts of bridge wing repeaters should be checked to ensure that they are in good condition and capable of operating satisfactorily.

6.2.7) Where the gyro compass or any repeaters are not correctly aligned, the Master should be requested to carry out realignment before the ship sails.

(Ref. SOLAS V/19.2.4)

7.1) The revised Chapter V includes Nautical Charts under Navigational Systems and Equipment in Regulation 19.

Guidance note on carriage of paper charts is contained in ANNEX 3. Nautical charts and publications must comply with the definition in SOLAS V/2.2 and be issued “…officially by or on the authority of a Government, authorised Hydrographic Office or other relevant government institution and is designed to meet the requirements of marine navigation.” Although UK-registered ships will probably use the relevant UKHO charts and publications, surveyors should note that charts and publications issued by other hydrographic authorities may also be encountered and they are acceptable as long as they meet the SOLAS V definition. Surveyors who are in any doubt about particular publications should refer to MCA Headquarters.

    7.1.1) Charts and publications must meet the requirements of planning and executing the intended voyage and be corrected and up to date in accordance with the requirements of SOLAS V/ Evidence that corrections have been made should be checked.

    7.1.2) The new Chapter V permits the carriage of Electronic Chart and Information Systems (ECDIS) to meet the chart carriage requirements. Surveyors should ensure that the system in use is an approved ECDIS using official Electronic Nautical Chart (ENC) data and that back-up arrangements are in place in accordance with SOLAS V/ Some systems are marketed which do not use official data. These are defined as Electronic Chart Systems (ECS) and do not meet the IMO ECDIS Performance Standards. Ships equipped with ECSs should therefore meet the chart carriage requirements by using an up to date folio of paper charts.

    7.1.3) In areas where no ENC data is available ECDIS may be used in “Raster” mode (Raster Chart and Display System – RCDS,) using Raster Nautical Charts (RNCs). In such cases the additional requirements for backing up the RCDS must be met.

    7.1.4) Refer to ANNEX 14 - ECDIS Guidance Notes and IMO Circular 207 for further information on Electronic Charts. The IMO Circular (which is due to be revised in 2007,) explains the difference between RCDS and ECDIS

(See also SOLAS V/ and 2.7.1)

8.1) Siting of the antenna unit

8.1.1) Siting of a radar antenna needs careful consideration so that a suitable compromise is reached which takes into consideration the effect of height on range performance and sea clutter, physical integrity and the need to minimise shadow sectors and false echoes through reflection.

8.1.2) Maximum radar range is dependent, amongst other factors, upon antenna height. However, whilst an increase in antenna height increases the radar range, it also increases the amplitude and extent of sea clutter. The echoes of buoys and small craft within the area of sea clutter may not always be conspicuous.

8.1.3) The physical structure supporting the radar antenna must be substantial enough to prevent twist which would cause bearing errors. The supporting structure must not allow/introduce excessive vibration which may degrade performance, reduce reliability and lead to early failure.

8.1.4) Shadow Sectors and False Echoes Interaction of the antenna beam with the structure of a vessel will impact upon the performance of the radar through:

  • Blockage whereby structures such as masts or funnels are directly in the path of the beam from the antenna to a target and thereby cause shadow sectors.

  • Reflection where energy from the antenna is reflected off part of the ship’s structure such as a mast, funnel or the deck and thereby causes false or distorted echoes.

    It should be noted that both blockage and reflection will occur with some structures such as masts or funnels and both effects influence radar performance. These effects are not only related to metallic structures - all objects, whether they are metal, plastic, wood, etc., can cause degradation in performance. As a general installation guideline, obstacles should not lie within the –10dB beamwidth of the antenna. Objects such as masts, posts and funnels in the horizontal plane of the antenna may lead to shadow sectors, ghosting and smearing. If they can not be eliminated they should be positioned at the greatest possible separation distance from the antenna. Objects within the –10dB elevation beamwidth of the antenna, i.e. 20° to 25° below the line of sight should also be avoided as they too cause degradation in performance; inclined deck areas within this region are a particular cause for concern. Raising the antenna so that it looks over obstructions may be an acceptable measure, particularly to avoid shadow sectors caused by the bow of the ship, provided the limitations mentioned in paragraphs 8.1.2 and 8.1.3 above are borne in mind. In ships that frequently navigate astern, the need to avoid shadow sectors astern should not be forgotten. The Surveyor should ascertain that the shadow sectors have been measured and recorded and are displayed adjacent to the radar. Following installation the angular width and bearing of any shadow sectors should be determined by the Master at the first opportunity and recorded. For a new ship, this should be done during trials, and kept up to date following any changes likely to affect shadow sectors. The cause and effect of changes in shadow sectors arising from temporary variations such as alterations in trim, the carriage of deck cargo and the stowage of derricks and cranes in different positions, should be recorded.

8.1.5) Fouling

The antenna unit should be mounted where there is least danger of its being fouled by halyards, derricks, radio antennae, etc. (see also paragraph 3.3.3).

8.1.6) Mutual Interference

Where two radar antennae are fitted near to each other, they should be so sited as to reduce the risk of damage to either radar due to radiation from the other radar.

8.2) Display units

The main display units should be sited on the bridge from which the ship is normally navigated. The following are some of the factors that should be borne in mind when selecting the most convenient site for the unit:

a) Compass safe distances. The permissible separation of the unit from magnetic compasses may dictate the site.

b) Lighting. The small amount of light issuing from the display unit may be enough to interfere with visual lookout when the bridge is in darkness; and there will be occasions when additional light is needed at the display unit either for comparison of the display with a chart or for running repairs to the unit. Conversely, there may be times when ambient light on the bridge is too strong for effective viewing of the display. Difficulties such as the foregoing may be overcome by the use of display visors.

c) Direction of view. At least one display unit should be so sited that an observer faces forward when viewing it, and is readily able to maintain a visual lookout.

d) Azimuth stabilization. Surveyors should check that the display is provided with an input from a heading sensor.

8.3) Waveguide and cable runs installation and inspection

Waveguide and cable runs should be installed in accordance with manufacturer's instructions and good engineering practices.

8.3.1) Inspection of waveguide and microwave co-axial cables Radar feeder runs are constructed from either waveguide or co-axial cable. The following types are in general use:

a) Rigid waveguide with a rectangular cross section;

b) Semi-rigid waveguide, usually with an elliptical cross section;

c) Flexible waveguide, usually with a rectangular cross section; and,

d) Microwave co-axial cable.

Flexible waveguide should not be used for long runs as the losses in this type of waveguide are high. However, it can be used in short sections to overcome some of the physical constraints of a rigid or semi-rigid waveguide. General considerations:

a) To minimise losses, waveguide or co-axial cable runs should be kept as short as possible and the number of connections should be kept to a minimum.

b) Where practicable, the number of bends and offsets should be reduced by going through, rather than round an obstruction.

c) The route should not introduce any straining of the waveguide or co-axial cable.

d) Where practicable, the waveguide or co-axial cable runs should be protected from accidental damage by ensuring that any sections exposed to risk are adequately protected.

e) The waveguide or co-axial cable run should be adequately supported and secured along its length.

f) In order to minimise condensation, where practicable, the run should be routed to avoid rapid variations in temperature along its length.

g) Waveguide and co-axial cables should not be run on any surface or in any area where they may be damaged by heat.

h) The re-use of feeder runs following an equipment change should only be undertaken if the feeder run is found by inspection to be satisfactory. Existing feeder runs should not be re-used if they have any external signs of damage or corrosion. Rigid waveguide:

a) Rigid waveguide should not be distorted. Bends and twists should only be formed using the correct tools and jigs. Flexible waveguide may be used to bridge unavoidable offsets or changes in orientation.

b) A continuous rigid waveguide run should not be secured to surfaces which may move with respect to each other; or where such surfaces are likely to have differing frequencies of vibration. Flexible waveguide should be used to overcome such problems.

c) All waveguide couplings should be accessible. Where waveguide is run behind panelling details of the route and the access points should be available. Semi-rigid waveguide:

a)The radii of bends in semi-rigid waveguide and their rates of twist should not, respectively, be less than the minimum bending radii or exceed the maximum twist rates quoted by the manufacturer.

b) While semi-rigid waveguide is more tolerant of movement than rigid waveguide, manufacturers' recommendations regarding the bridging of surfaces which may move with respect to each other should be observed. Flexible waveguide:

a) Two types of flexible waveguide are in general use, those which are designed only to bend and those which will also tolerate a twist. The radii of bends and, where appropriate the rate of twist of flexible waveguide should not respectively, be less than the minimum bending radii or exceed the maximum twist rate quoted by the manufacturer.

b) Flexible waveguide should not pass through any form of compression gland.

c) Flexible waveguide should not be stretched. Microwave co-axial cable:

a) Microwave co-axial cable should preferably be run in a single continuous length between transceiver and scanner.

b) The radii of bends of co-axial cable should not be less than the minimum bending radii quoted by the manufacturer.

c) To provide some resilience to vibration and to permit repair of cable terminations, it is advisable for some slack to be left at either end of the cable.

8.4) Operational checks

8.4.1) Surveyors should check the overall performance of the radar installation by careful observation of known echo responses in the vicinity of the ship. This is a subjective method and relies on the judgement of the surveyor with experienced appreciation of the quality of a radar picture which can be obtained in the area.

8.4.2) The operation of Performance Monitors should also be checked and, where possible, the monitor responses should be compared with the calibration label or record.

8.4.3) The alignment of the radar heading-marker with the ship's fore-and-aft line should be checked by comparing visual bearings, relative to the ship's head, of identified radar echoes with the bearings on the display between the echoes and the heading line. The visual bearings should, where practicable, be taken from positions which do not introduce parallax into the alignment procedure. Where inter-switching facilities are provided the Surveyor should ensure that the indicated heading marker is accurately aligned with all arrangements of units. Where the heading marker is not accurately aligned, the Master should be informed and be requested to carry out a re-alignment before the ship sails.

8.4.4) Where electronic plotting aids are provided with test programmes or facilities to enable the integrity of the equipment to be checked, as described in the Operating Manual, Surveyors should make use of these test programmes or facilities when assessing the performance of the radar installation.

8.5) Measurement of Shadow Sectors

8.5.1) Calculation from a knowledge of the width of a mast or other object which might cause a shadow, and its bearing from the centre of the radar antenna, can provide a useful guide to the possible appearance of shadow sectors on a radar display. However, the actual angular width and bearing on any shadow sectors should be determined at sea. Two possible methods are:

a) Observations of the behaviour of the echo of a small isolated object, such as a buoy not fitted with a corner reflector or a beacon post, when the ship is turned slowly through 360° at a distance of a mile or so from the object. The display unit should be carefully watched, and the bearings between which the echo from the buoy disappears and re-appears taken as indicating the shadow sector or sectors. The sea should be calm so that the echo is not lost in the sea clutter or submerged or hidden by waves from time to time, or in the case of a buoy or other floating objects the echo fading temporarily due to any rolling motion.

b) Observation of the shadow sector against a background of sea clutter.


A shadow sector cannot be fairly estimated in heavy clutter, as echoes from either side of the sector may spread into it and give an illusion that objects in the sector are being observed. Nor can it be satisfactorily determined in confined water, because of the probability of indirect, false or multiple echoes being produced from nearby buildings or other ships.

8.6) Radar plotting facilities

8.6.1) SOLAS V/19 specifies carriage of three types of radar plotting aid. The type carried depends upon the size of the ship. Each plotting aid forms an integral part of the radar unit. Surveyors should check that accurate heading and speed information is input to the equipment and that the speed is measured through the water in the fore and aft direction. Surveyors should check that GPS is not being used to provide speed information for ARPA and ATA. GPS provides speed over the ground and the ARPA/ATA display will be misleading in sea areas that experience significant tidal steams and currents if used for collision avoidance.

All plotting aids must provide target information which must include plot number, range and bearing, CPA and TCPA, and true course and speed.

ANNEX 16 - Radar Equipment explains the difference in capabilities between each type. Electronic Plotting Aid (EPA) Surveyors should, if possible, check that at least 10 targets can be manually plotted with selectable true and relative vectors on at least the 3,6 and 12 nm. range scales.

8.6.2) Automatic Tracking Aid (ATA) Surveyors should check, if possible, that at least 10 targets can be acquired and automatically tracked with selectable true and relative vectors on at least the 3,6 and 12 nm. range scales. Auto-tracking must be able to trigger an alarm when a target transits a selected zone or range, CPA, TCPA and when a target is lost.

8.6.3) Automatic Radar Plotting Aid (ARPA) Surveyors should check, if possible, that at least 20 targets can be acquired both manually and automatically. ARPA must be able to be sea or ground stabilised. ARPA must be able to trigger an alarm when a target transits a selected zone or range, CPA, TCPA and when a target is lost. A trial manoeuvre facility must be provided to assess the effect of any proposed manoeuvre of own-ship. The ARPA should be provided with test programmes to enable the integrity of the equipment to be checked. These are described in the Operating Manual. Surveyors should make use of these test programmes or facilities when assessing the performance of an ARPA


9.1) General

9.1.1) V/ requires all ships of 300gt and over to be fitted with SDME which measures speed through the water. Devices which can measure water track or ground track (such as Doppler receivers) are acceptable, but the input to the Radar equipment must provide water-track.

9.1.2) Ships of 50000 gt and over are required to be fitted with SDME which measures speed and distance over the ground in both forward and the athwartships directions, as well as the water track. Input to the radar must still be water track.

9.2) Siting

The SDME transducer unit should be sited so as to avoid, where practicable, the vicinity of all underwater openings in, or projections from, the hull, such as plugs, anodes or other transducers, so that satisfactory overall performance can be achieved. The guidance in Section 4.1 may be used for the siting of underwater transducers for Doppler logs.

9.2.1) If a towed log is fitted, the position of the log register should be selected so that the log line and its rotator, when streamed, are as clear as is practicable from disturbed water in the close vicinity of the ship and so that the rotation of the log line is not impeded by any part of the ship or its equipment.

9.2.2) Siting of the transducer for electro-magnetic (EM) speed and distance measuring devices. The transducer position is of prime consideration when fitting EM SDME. The ideal position is one in which there is 'solid' water free from aeration beneath the transducer. It should, in any case, be mounted so that its electrodes are submerged at all times. There are only a few positions in a ship which are suitable in every respect, and moreover a position found to be satisfactory in one design of ship will not necessarily produce equally good results in another. To avoid aeration the hull fittings for the transducer should be installed in the forward part of a ship where the boundary layer thickness and turbulence are minimal, in a position forward of any projections, outflows etc. and away from any Bar and Bilge keels. Probe or projecting type sensors may be satisfactorily installed in other parts of a ship, but should be fitted in accordance with the manufacturer's recommendations. Other factors which should be borne in mind when fitting the transducers are as follows:

a) The orientation of the transducer should be as indicated in the equipment handbook.

b) The transducer should be fitted in a position having dry access as it may have to be removed for cleaning or servicing.

c) It is essential that no grease or anti-fouling paint covers the transducer electrodes. Should this occur it will prevent the correct operation of the equipment.

d) The wiring between the transducer and the electronics unit should conform to the recommendation of the manufacturer.

9.2.3)The bridge display should be sited in a position to facilitate easy access and viewing and where the effect of any lighting necessary for the equipment does not interfere with the keeping of an effective look-out.

(Ref. SOLAS V/

10.1) Siting

SOLAS V/19 requires Rate of Turn indicators to be fitted to all ships of 50000gt and over.
Where appropriate the display should be sited on the bridge in a position to facilitate easy access and viewing, and where the effect of any lighting necessary for the equipment does not interfere with the keeping of an effective look-out.

(Ref. SOLAS V/

11.1) All ships irrespective of size are required to be fitted with a GNSS receiver. This will probably be a GPS receiver using the US Global Positioning System which may or may not be equipped to provide differential correction (DGPS). The Russian GLONASS system or a terrestrial navigation system receiver will also meet the requirements of SOLAS V/19.

11.2) Particular attention should be paid to the correct data inputs / outputs. Particular attention should be paid to the antenna and its connections.

11.3) GNSS receivers also calculate speed over the ground. Surveyors should ensure that speed input to the radar is not generated by GNSS, as the radar requires water-track speed.


(Ref SOLAS V/19.2.4)

12.1) Automatic Identification Systems must be fitted to all new ships of 300gt and upwards on international voyages and 500gt and upwards on non-international voyages. Existing ships must be fitted with AIS according to the timetable set out in SOLAS V/19.2.4.

Full details of AIS carriage requirements are set out in ANNEX 17 which includes the IMO Guidelines on the installation of AIS on board ships (SN/Circ.227)

12.1.1) The AIS unit will provide identification of other vessels similarly equipped and provide their position course and speed and other important information.

12.1.2) Surveyors should check that the required equipment interfaces are operating correctly and that accurate own-ship data is being received by the AIS equipment.

12.1.3) ANNEX 17 - Guidance Notes and IMO Guidelines should be referred to. This contains a table of the information the AIS transmits.

12.1.4) Surveyors should check that the “Static” (identification) information has been programmed correctly into the AIS, that Navigational Status can be changed as required and that “Voyage Related” data can be entered and changed easily when required.

12.1.5) The MCA’s Guidance for this new equipment is contained in ANNEX 17 and warns particularly about using AIS for collision avoidance and the dangers of using VHF in collision avoidance situations.

12.2) Surveyors in the Dover area can request help from Dover Coastguard in checking the operation of the AIS. The screens in Dover Coastguard station display all the AIS information. Surveyors elsewhere can request help from Coastguard centres using their Euronav system. This can be done with the Euronav by Coastguard making an area call around the ship or by a poll to the ship MMSI.

12.2.1) The Euronav system does not provide all the information provided by the AIS but the following should be received:

Position (obtained by putting the cursor over the target and reading from the tool bar)

Ship Type (but may not be present as this is not mandatory in the specification)

12.2.2) The information can be requested from “VTS” in the tool bar followed by “Properties” and “DATA REQUEST”. Do not tick the “Enable” box in “Course of Vessel” or COG is unlikely to be returned. Select returns from the “MMSI Poll” tick boxes but remember that only three can be returned in any poll so do not check more than three at a time. Also COG/SOG counts as two.

12.2.3) The information displayed on the screen can be set in “DISPLAY SETTINGS”. All the boxes can be ticked. Alternatively the full information for a target can be obtained by right clicking on the target but the click needs to be deliberate – held down for a second or so. A shorter click is interpreted as a change to the chart scale.

12.2.4) Further help can be provided by the Navigation Safety Branch at Southampton 02380 329146.

            RECORDER (S-VDR)

         (Ref. SOLAS V/20 and SOLAS V/18.8)

13.1) Voyage Data Recorders are required to be fitted to all passenger ships, and other ships of over 3000 gt. according to the timetable in SOLAS V/20 and ANNEX 10. Existing ships, other than ro-ro passenger ships, may be exempt from fitting a VDR if fitting one has been deemed by the Administration to be unreasonable and impracticable (SOLAS V/20.3). However under SOLAS V/20.2 existing cargos ships should be fitted with Simplified Voyage Data Recorders (S-VDRs) according to the given timetable. Additional carriage requirements under EU legislation are given in ANNEX 10.

13.2) VDRs are subject to an annual performance check under SOLAS V/18.8 and details of the test and certification for UK ships is given in ANNEX 10.

13.3) Surveyors should check the situation of the VDR and the connections to the interfaced items of equipment. They should also check the mandatory performance check certificate is in date and that mandatory routine maintenance has been completed and entered in the ships planned maintenance log. When the annual performance check is due the procedures laid down in ANNEX 10 should be followed.

13.4) On initial installation of a VDR system, or after significant refit work affecting the system, surveyors should satisfy themselves that a VDR system installation test has been completed. This should ensure that all sensors and associated interfaces are fully operational and that all sensor data can be faithfully recorded and accurately and unambiguously reconstructed.

(Ref. SOLAS V/

14.1) Integrated Bridge Systems (IBS) are defined as a combination of systems which are interconnected in order to access sensor information or command/control from workstations in order to increase safe and efficient bridge management.

14.2) Integrated Navigation Systems (INS) are designed to evaluate and combine the inputs from several sensors, to provide navigational information, warning of dangers and indication of degradation of information integrity.

14.3) Failure of one IBS sub-system must trigger a visual and audible alarm and must not cause failure of any other sub-system

14.4) Should a sub-system of an INS fail the watchkeeper should be able to operate all the other components of the system independently.

14.5) Watchkeepers must be familiar with the operation of IBS and INS and in particular must be familiar with the alarms and be able to operate any over-ride arrangements in case of a system failure. Clear instructions must be available for the systems.

14.6) Integrated Bridge Systems (IBS) must comply with the IMO Performance Standards for Integrated bridge Systems - MSC.64(67). To demonstrate such compliance the MCA requires documented evidence in the form of a Failure Mode Effects Analysis (FMEA).


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