SOLAS Chapter V: Safety of Navigation

Background

Scope and structure of Chapter V

Chapter V is unique among the chapters of SOLAS. Unlike Chapter II-1, Chapter II-2, Chapter III and Chapter IV, which apply only to ships of specified size on international voyages, Chapter V applies to all ships on all voyages. The reason is the practical reality of navigation: collisions, groundings and search-and-rescue obligations involve all classes of vessel, and a regulatory floor that addresses only large international ships would leave a wide swathe of the world’s traffic outside the navigational-safety framework.

The chapter is sequentially numbered with no internal Parts. Regulations cover, in clusters:

• Application and definitions (Regulations 1 to 2).
• Search and rescue, distress messages and emergency response (Regulations 3 to 12, plus 33).
• Navigational information services (Regulation 13).
• Ship reporting and ship routeing (Regulations 10 to 11).
• Manning of ships (Regulation 14).
• Bridge design and equipment (Regulations 15 to 18).
• Carriage of navigational equipment (Regulations 19 and 19-1).
• Voyage data recorder (Regulation 20).
• International Code of Signals and IAMSAR (Regulation 21).
• Navigation bridge visibility (Regulation 22).
• Pilot transfer arrangements (Regulation 23).
• Track control, electrical power and steering gear (Regulations 24 to 26).
• Charts and publications (Regulation 27).
• Records of navigational activities (Regulation 28).
• Life-saving signals and operational limitations (Regulations 29 to 30).
• Danger messages and distress messages (Regulations 31 to 33).
• Safe navigation and misuse of distress signals (Regulations 34 to 35).

The Reg V/2 application calculator returns the applicable Regulations for a given ship and voyage.

Chapter V is closely interlocked with Chapter IV (the Global Maritime Distress and Safety System, GMDSS), with the STCW Convention (Standards of Training, Certification and Watchkeeping), with the COLREGs Convention (Collision Regulations), and with the ISM Code (Safety Management). The bridge of a modern merchant ship operates as a system of systems, each governed by its own piece of regulation but integrated through bridge resource management and through the master’s overarching responsibility for safe navigation.

Major amendment history

Chapter V has been substantially revised three times since 1974:

• 1995 amendments revised the carriage requirements for navigational equipment to reflect the rapid advance of electronic navigation since the 1974 text was drafted. The amendments added GPS as a primary position fix source and updated radar performance standards.
• 2002 amendments (entered into force 2002) introduced mandatory AIS Class A on all SOLAS ships, mandatory VDR on passenger ships and on cargo ships of 3,000 GT and above (with S-VDR for older cargo ships), and reformed the bridge ergonomic requirements. The 2002 cycle was the largest single revision of Chapter V since 1974.
• 2002 to 2010 ECDIS phase-in established the staged mandatory ECDIS schedule running from 2012 (passenger ships of 500 GT and above on international voyages) to 2018 (cargo ships of 10,000 GT and above on international voyages). The phase-in coincided with the development of the IHO ENC distribution system and the ECDIS performance standards.
• 2008 LRIT amendments introduced Long-Range Identification and Tracking under Regulation 19-1, providing flag-state and coastal-state visibility into international shipping movements.
• 2011-2014 BNWAS phase-in introduced the bridge navigational watch alarm system on a staged schedule.
• 2014 amendments introduced the polar water operational manual under Polar Code interaction.
• 2018 amendments updated the carriage tables for the 2020 entry into force of the carriage of e-navigation equipment.

The amendment cycle reflects the rapid technological change of the post-1995 period. Where Chapter II-1 amendments are typically driven by post-incident analysis of casualties, Chapter V amendments are typically driven by new technology (AIS, ECDIS, LRIT, e-navigation) becoming sufficiently mature for mandatory carriage.

Application (Regulation 1) and definitions (Regulation 2)

Chapter V applies to all ships on all voyages, with specific Regulations modifying the scope (for example Regulation 14 manning applies in a slightly different way to passenger ships). The definitions in Regulation 2 cover terms used throughout the chapter: all ships, length, breadth, gross tonnage, plus terms specific to navigation such as bridge wing, navigational watch, look-out, ship routeing system, ship reporting system.

The Reg V/2 application calculator returns the applicable provisions for a given ship and route.

Search and rescue, distress messages and emergency response

Search and rescue services (Regulation 7)

Each contracting government undertakes to ensure that arrangements for distress communication and coordination are in place to provide rescue of persons in distress at sea around its coasts. Coordinated search and rescue services are organised under the framework of the International Convention on Maritime Search and Rescue (SAR Convention) 1979 as amended, and the IAMSAR Manual (International Aeronautical and Maritime Search and Rescue Manual) provides the operational doctrine.

The world’s oceans are divided into Search and Rescue Regions (SRRs), each with a designated Rescue Coordination Centre (RCC) that coordinates SAR operations within its region. Each contracting state maintains an RCC (or arranges for an RCC to be operated by a partner state). The RCC operates 24 hours a day with maritime English language proficiency and access to the full Cospas-Sarsat alert distribution.

When a distress alert is received (via Cospas-Sarsat EPIRB activation, Inmarsat satellite distress, AIS-SART activation, VHF DSC distress alert, MF DSC distress alert, or by visual observation), the RCC:

• Acknowledges the alert.
• Determines the location and nature of the distress.
• Alerts SAR units (coast guard cutters, naval vessels, commercial ships in the area, helicopters, fixed-wing aircraft).
• Coordinates the response with the on-scene SAR Mission Coordinator (typically the most-suitable vessel or aircraft on scene).
• Reports through the SAR network to coastal authorities and to the flag state of the distressed vessel.

Search and rescue services from ships (Regulation 33)

Every master receiving a signal of distress at sea or aware of a person in distress is bound to proceed with all speed to provide rescue assistance, informing the persons in distress and the rescue coordinating authority that he is doing so, unless excused or already engaged in rescue. Failure to render assistance is an offence in most flag states.

The “all speed” requirement is qualified by the master’s professional judgement: if the master can reach the distress location significantly faster by altering course than other vessels, the obligation is strong; if the master is far away or has compelling reasons (his own ship in distress, hazardous cargo precluding rescue operations), the obligation may be reduced. The master remains accountable for the decision and must record the reasoning.

The Reg V/33 distress messages calculator walks through the master’s obligations and reporting paths.

AMVER and ship reporting systems

The AMVER (Automated Mutual-Assistance Vessel Rescue System) is a voluntary ship reporting system run by the US Coast Guard, with participation from over 20,000 ships at any time. Participating ships submit position reports every 24 hours; in case of distress, the AMVER database identifies all participating ships within a defined area for the SAR coordinator to alert.

Other reporting systems (similar voluntary systems run by Australian Maritime Safety Authority, Japanese Coast Guard, Norwegian Coastal Administration, etc.) provide regional coverage. Mandatory reporting under SOLAS V/11 covers specific high-risk areas with reporting positions, content and frequency prescribed by IMO.

Hampered ships and dangerous areas (Regulations 31 to 32)

The master of any ship encountering dangerous ice, dangerous derelict, tropical storm, sub-freezing air temperatures associated with gale-force winds causing severe icing on superstructures, or winds of force 10 or above on the Beaufort scale for which no storm warning has been received, is bound to communicate the information by all means at his disposal to ships in the vicinity and to the appropriate authorities ashore.

The “danger message” obligations are intentionally broad to capture both routine hazards (a derelict drifting in shipping lane) and unforeseen events (a tsunami passing through the route). The reporting medium is now typically Inmarsat SafetyNET or NAVTEX, with formatted messages that integrate into the worldwide navigational warning service.

Navigational information services

Navigational warnings (Regulation 13)

Each contracting government must arrange for the publication of nautical and meteorological information of importance to safe navigation:

• NAVAREA warnings: long-range broadcasts on the Worldwide Navigational Warning Service (WWNWS), divided into 21 NAVAREAs covering the world’s oceans, each operated by a coordinating state. NAVAREA warnings are transmitted via Inmarsat SafetyNET satellite broadcast and are received automatically by ships’ Inmarsat-C terminals.
• Coastal warnings (METAREA, NAVTEX): shorter-range broadcasts of warnings specific to coastal waters, transmitted on NAVTEX (490 and 518 kHz) by coastal stations. NAVTEX receivers automatically print incoming warnings on board.
• Local warnings: very local warnings (specific harbour, specific channel) transmitted by VHF and other local means.

Receipt is the master’s responsibility either through equipment carried on board (Inmarsat SafetyNET, NAVTEX) or through the GMDSS sea-area facilities listed in Chapter IV.

Meteorological information

In parallel with NAVAREA warnings, the WMO (World Meteorological Organization) and IMO coordinate the broadcast of meteorological information for shipping:

• Weather forecasts for the open ocean covering wind, sea state, visibility, ice and tropical storms.
• Tropical storm warnings with cone-of-uncertainty and projected track.
• Ice warnings for polar regions and seasonal ice extents.
• Tsunami warnings for affected oceans.

These warnings are integrated with the NAVAREA broadcast structure and similarly received via Inmarsat SafetyNET and NAVTEX.

Ship routeing systems and ship reporting systems (Regulations 10 to 11)

The IMO adopts ship routeing systems (Traffic Separation Schemes, two-way routes, recommended routes, deep-water routes, areas to be avoided) and ship reporting systems (mandatory or recommended reporting at boundary lines or fixed positions) that contribute to safety of navigation, prevention of pollution, and protection of marine environment.

The major TSS clusters are around the Strait of Malacca, the Suez Canal and the Panama Canal approaches, the English Channel, the Strait of Gibraltar, the Bosporus, the Strait of Otranto, the Pentland Firth, and many port approaches. Ship routeing systems use:

• Traffic Separation Scheme (TSS): parallel one-way lanes separated by a separation zone, within which traffic flows in defined directions.
• Two-way routes: routes used by traffic in both directions but staying within the route boundaries.
• Deep-water routes: routes for deep-draft vessels, with depth and obstruction characteristics established by hydrographic survey.
• Recommended tracks: less formal recommendations, often based on commercial habit.
• Areas to be Avoided (ATBA): areas closed to ships above a certain size, type, or with certain cargo, typically for environmental protection or safety reasons.

Ship reporting systems require participating ships to report at boundary entries, every defined interval, at significant events, and at boundary exits.

Manning of ships (Regulation 14)

Every ship must be manned by a sufficient and effective complement to support safe navigation. The detailed manning standards are set in the STCW Convention and the corresponding STCW Code; SOLAS V/14 cross-refers and adds specific bridge-watch requirements:

• A sole look-out function may be combined with the helmsman function only in defined conditions (clear weather, low traffic density, master’s authorisation, fatigue management).
• The minimum bridge watch is one navigational officer plus one rating; on passenger ships and on ships in restricted visibility or busy waters, additional ratings or officers are required.
• The watch composition is set in the ship’s Minimum Safe Manning Document, issued by the flag state, which lists the minimum certified complement by rank and rating.
• The watch must be relieved at intervals consistent with the STCW hours-of-rest requirements (10 hours rest in 24 hours, 77 hours rest in 7 days, with limited exceptions).

Bridge resource management (BRM) under STCW Section A-VIII/2 requires the watch to operate as a coordinated team, with delegation, communication protocols, situation awareness, and challenge-and-response procedures. BRM training is mandatory for officers in charge of a navigational watch under STCW.

The Reg V/14 manning calculator returns the bridge-watch composition for a given ship in a given operational condition.

Bridge design and equipment

Bridge design (Regulation 15)

Regulation 15 imports the IMO ergonomic and human-factors guidelines for bridge design (Resolution MSC.252(83) and successor amendments). Requirements include:

• Bridge layout supporting one-man bridge operation in normal conditions, with all primary navigational functions accessible from a single position.
• Workstation design (sit-stand, anti-glare displays, day/night display modes, alarm prioritisation).
• Conning information presentation (heading, course, speed, depth, position) integrated and consistent across displays.
• Alarm management to avoid nuisance alarms while maintaining critical alarm visibility.
• Bridge wing accessibility for visual lookout and for berthing operations, with controls for engine, helm, and side-thrusters available at the wings.
• Sufficient unobstructed bridge floor area for bridge team movement during periods of restricted manoeuvrability.
• Communication paths between conning position, bridge wings, chart table, radar and ECDIS positions sufficiently brief.

The Reg V/15 bridge design calculator returns the design checklist for a given ship type.

Maintenance of equipment (Regulation 16) and EMC (Regulation 17)

Equipment carried under Chapter V must be maintained so that it operates effectively at all times. Regulation 17 requires that bridge-installed equipment satisfy electromagnetic compatibility requirements (the IEC 60533 standard is the typical reference) so that one piece of equipment does not interfere with another, and that the bridge environment as a whole is not corrupted by electromagnetic emission from anywhere on the ship.

Specific maintenance practices include:

• Annual class-witnessed verification of compass deviation, gyro performance, radar accuracy, and AIS message transmission.
• Periodic battery replacement on EPIRBs, AIS, and other equipment.
• Software updates on ECDIS, AIS, and radar to maintain compliance with current performance standards.
• Calibration of speed log, echo sounder, and rate-of-turn indicator against reference values.

Approval and performance standards (Regulation 18)

Equipment carried under Regulation 19 must be type-approved by the flag state (typically through delegation to a classification society) against the IMO performance standards. The performance standards are individual IMO Resolutions (MSC.232(82) for ECDIS, MSC.302(87) for AIS Class A, MSC.192(79) for radar, etc.) and are imported by reference.

Type-approval testing covers:

• Functional performance against the standard.
• Environmental performance (vibration, temperature, humidity, salt fog, ingress protection).
• Electrical safety and EMC.
• Software validation for safety-critical functions.

The Reg V/18 performance standards calculator returns the relevant performance standard for a given equipment item.

Carriage requirements (Regulation 19)

Regulation 19 is the heart of Chapter V. It sets out a table of equipment that must be carried, with thresholds keyed to ship size and route. The major items are:

Magnetic compass and gyrocompass

• Magnetic compass: standard magnetic compass, gimbal-mounted in a binnacle on the centreline, with bearings transmitted to the steering position; carried by all ships. Adjustments and a deviation card must be maintained. The deviation card lists the residual deviation by ship’s heading and is corrected after major modifications, after periods alongside steel structures, or when deviations exceed acceptable limits.
• Gyrocompass: required on ships of 500 GT and above, with bearing repeaters at the standby steering position and at the bridge wings, and integration with the autopilot. The gyrocompass provides heading reference independent of magnetic disturbances; modern installations include a fibre-optic gyrocompass or laser-ring gyrocompass which has higher accuracy and faster startup than the traditional spinning-mass gyrocompass.

Radar

• 9 GHz X-band radar required on all ships. X-band has finer azimuth resolution and better detection of small targets but suffers in heavy precipitation.
• 3 GHz S-band radar additional, required on ships of 3,000 GT and above. S-band complements the X-band by providing better long-range performance in heavy precipitation.

Modern radar features include:

• Auto-tuning to optimise sensitivity to ambient conditions.
• Sea clutter and rain clutter suppression with adjustable thresholds.
• Target tracking (mini-ARPA) integrated with the radar without separate ARPA.
• AIS integration showing AIS targets overlaid on the radar picture, with vessel name, heading and speed.
• Trial manoeuvre capability simulating proposed course/speed changes.
• Chart radar overlay showing the ENC chart over the radar picture.

ARPA, AIS, GPS

• ARPA (Automatic Radar Plotting Aid) required on ships of 10,000 GT and above, with target tracking, CPA / TCPA computation, vector display and trial manoeuvre. ARPA tracks up to typically 50 to 100 simultaneous targets.
• AIS Class A required on all SOLAS ships of 300 GT and above on international voyages and 500 GT on domestic voyages, plus all passenger ships. AIS provides automatic ship-to-ship and ship-to-shore broadcast of identity, position, course, speed and other navigational data via two VHF maritime frequencies (161.975 MHz and 162.025 MHz) using SOTDMA (Self-Organising Time Division Multiple Access). The AIS message structure includes:
  • Static data (MMSI, IMO number, ship name, ship type, dimensions): transmitted every 6 minutes.
  • Dynamic data (position, course over ground, speed over ground, heading, navigation status): transmitted every 2 to 12 seconds depending on ship speed and turn rate.
  • Voyage data (destination, ETA, draught, navigational status): transmitted every 6 minutes.
  • Safety messages (binary text): on demand.
• GPS receiver (or other GNSS receiver such as GLONASS, Galileo, BeiDou) is the primary position fix source. WAAS / EGNOS / SBAS-corrected receivers are commonly carried for additional accuracy (typical accuracy 1 to 3 metres with augmentation, 5 to 10 metres without). DGPS (Differential GPS) using shore-based correction transmitters provides similar accuracy in coastal waters.

ECDIS

• ECDIS with backup arrangement (paper charts as backup, or a second independent ECDIS) required on staged thresholds:
  • From 2012: passenger ships and tankers of 500 GT and above on international voyages.
  • From 2014: cargo ships of 50,000 GT and above on international voyages.
  • From 2018: cargo ships of 10,000 GT to 50,000 GT.

ECDIS uses Electronic Navigational Charts (ENCs) issued by national hydrographic offices and updated through Notice to Mariners and chart correction broadcasts. The current encoding standard for ENC is S-57 (transitioning to S-100 through the 2020s); the ENC covers the world’s oceans through coordinated production by IHO member hydrographic offices.

ECDIS features include:

• Display of own ship’s position with course-over-ground vector, heading, speed.
• Route planning and monitoring with cross-track error and waypoint approach alarms.
• Anti-grounding with safety contour and depth-by-time projection.
• Track recording and replay.
• AIS overlay showing nearby ship positions and identities.
• Radar overlay (where the radar provides ECDIS-compatible data).
• Notice-to-Mariners updating with manual or auto-update from the chart provider.
• Day/night/dusk colour palettes.
• Alarms for crossing safety contour, approaching shallow water, leaving the planned route.

Echo sounder, speed log, rate-of-turn indicator

• Echo sounder required on all ships, displaying water depth under the keel. The echo sounder’s accuracy depends on the seawater temperature, salinity and the transducer mounting. Modern echo sounders are dual-frequency for better resolution in shallow water and longer range in deep water.
• Speed and distance log measuring through water on all ships, plus speed-over-ground for ships of 50,000 GT and above. The through-water log is typically a Doppler log measuring speed of water past the hull; the over-ground log derives from GPS or from a Doppler log that locks on to the seabed in shallow water.
• Rate-of-turn indicator required on ships of 50,000 GT and above. Provides instantaneous turn rate (degrees per minute) for fine-control manoeuvring.

Sound reception system

• Sound reception system allowing the officer of the watch to hear sound signals from outside the bridge when the bridge is fully enclosed; required on all ships with closed bridge. The system uses external microphones with bridge speakers, allowing the watch to hear the sound signals (whistle, foghorn, bell) of nearby vessels per the COLREGs.

BNWAS (Regulation 19, post-2014)

• Bridge Navigational Watch Alarm System (BNWAS) required on all SOLAS ships, phased in 2011 to 2014. The BNWAS detects watchkeeper incapacitation by requiring acknowledgement of a periodic prompt; if no acknowledgement, the system escalates the alarm to the master and to the off-duty crew. The escalation pattern:
  • Stage 1: visual indicator on the bridge, requiring acknowledgement within typically 3 minutes.
  • Stage 2: audible alarm on the bridge.
  • Stage 3: alarm in the master’s accommodation and selected officers’ accommodation.
  • Stage 4: alarm in all officer accommodation.
  • Stage 5: alarm to all crew.

The BNWAS calculator returns the configuration and alarm escalation timing.

LRIT (Regulation 19-1)

• Long-Range Identification and Tracking (LRIT) required on all SOLAS ships on international voyages, with periodic position reports (typically every 6 hours) transmitted via satellite to the flag state and to interested coastal states. LRIT data is used for:
  • Sovereign-domain awareness: coastal states tracking foreign-flag traffic in their EEZ.
  • Maritime security: identification of ships of interest under ISPS Code.
  • Search-and-rescue support: pre-positioning of SAR resources.
  • Flag-state oversight: monitoring of flagged-fleet operations.

LRIT transmissions are protected from modification (encrypted satellite link) and the data is held in regional LRIT data centres operated by IMO-approved providers.

The Reg V/19 carriage calculator returns the full equipment list for a given ship.

Voyage data recorder (Regulation 20)

The Voyage Data Recorder (VDR) is the maritime equivalent of the aviation flight data recorder. It records:

• Date and time (UTC).
• Ship position, heading, speed, water depth.
• Bridge audio (microphone-captured conversations and radio transmissions on bridge).
• Communication audio (VHF radio, internal communication).
• Radar image (one screen capture).
• ECDIS image (one screen capture if fitted).
• Engine and rudder orders and responses.
• Hull openings status (watertight doors, ramp doors, side doors, draft).
• Wind speed and direction.
• AIS data (own ship and target ships).
• Hull stress measurements on certain ship types.
• Speed log readings (water speed and ground speed).

VDR data is retained for at least 12 hours in the protected capsule (designed to survive sinking, fire, and impact, recoverable by ROV from depth) and longer in lighter on-board storage (typically 30 days).

The protected capsule is built to survive:

• 30 G impact for 11 milliseconds.
• 1100 degrees Celsius fire for 1 hour.
• 6000 metres of seawater immersion for 30 days (older capsules) or 60 days (newer).
• Locator beacon transmission for 30 days.

VDR is mandatory on passenger ships and on cargo ships of 3,000 GT and above on international voyages. S-VDR (Simplified VDR) is permitted on certain older cargo ships, recording a reduced parameter set.

The Reg V/20 VDR calculator and the VDR data parameters calculator return the carriage requirement and the parameter set.

International codes (Regulation 21)

Every ship covered by Chapter V must carry the International Code of Signals (a flag-and-signal vocabulary for ship-to-ship and ship-to-shore communication when languages differ) and the IAMSAR Manual Volume III (the on-scene SAR coordinator’s manual).

The International Code of Signals contains:

• Single-letter signals: each letter has a stand-alone meaning (“A: I have a diver down, keep clear”, “G: I require a pilot”, “O: Man overboard”, etc.).
• Two-letter signals for general meaning (“AB: I am abandoning my vessel”, “CD: I require immediate assistance, etc.).
• Three-letter signals for medical and procedural communication.
• Numeric signals for time, position, course and speed.

Modern use of the International Code of Signals is mostly limited to ceremonial flag display in port and as a backup when language is a barrier.

The Reg V/21 international codes calculator confirms the carriage requirement.

Navigation bridge visibility (Regulation 22)

Regulation 22 sets the bridge visibility envelope:

• The view of the sea surface from the conning position must not be obscured by more than the lesser of one ship length or two cables (about 365 m) ahead, in any condition of draft, trim, list and weather, regardless of cargo loading.
• The horizontal field of view from the conning position must extend over an arc of not less than 225 degrees from right ahead to not less than 22.5 degrees abaft the beam on either side.
• The view from each bridge wing must extend over an arc of at least 225 degrees, including 45 degrees on the opposite side from right ahead through forward, the beam, and 22.5 degrees abaft the beam on the same side.
• Blind sectors caused by deck cargo or cranes must be as few as possible, with no single blind sector exceeding 10 degrees, and the total of all blind sectors not exceeding 20 degrees. Blind sectors must be separated from each other by clear sectors of at least 5 degrees.
• The lower edge of the front bridge windows must be as low as possible to minimise blind area below the bridge wings; for cargo ships not exceeding 35 percent of the bridge floor height.
• The upper edge of the bridge windows must allow forward view extending up at least to a horizontal line for a person of average height standing at the conning position.

For container ships, the bridge visibility envelope is a particular design constraint because the high deck cargo can rapidly approach the visibility limits as the ship is loaded. Many large container ships have the bridge raised onto an extended superstructure to maintain visibility.

The Reg V/22 bridge visibility calculator and the wheelhouse visibility calculator compute compliance for a given bridge geometry and loading condition.

Pilot transfer arrangements (Regulation 23)

Pilot embarkation is one of the highest-fatality routine operations in shipping. Regulation 23 incorporates by reference the IMO Resolution A.1045(27) (Recommendations on Pilot Transfer Arrangements) which specifies:

• Pilot ladder of approved type, with the freeboard at the boarding place not exceeding 9 metres (above this, a combination of pilot ladder and accommodation ladder is required).
• Side ladders of correct width, step spacing, side ropes, and step material (synthetic-rope-fastened wooden steps are typical).
• Lighting at the boarding location.
• Lifebuoy with self-igniting light at the boarding location.
• Heaving line for retrieval if pilot falls.
• Pilot ladder embarkation height angle kept within designed limits (the pilot ladder angle calculator returns the maximum draft at which a pilot ladder of given length is compliant).
• Pilot transfer manual carried on board with the rigging procedure documented.
• Crew assistance during boarding with at least one competent crew at the entry point and one ready to assist with the heaving line.

The Reg V/23 pilot transfer calculator returns the equipment, training and procedural requirements.

The International Maritime Pilots’ Association (IMPA) maintains a database of pilot ladder defects observed during boardings. Common defects include:

• Steps with damaged anti-slip surfaces.
• Side ropes with chafe damage or improper splice.
• Magnet-type ladder hooks (forbidden by Resolution A.1045).
• Ladder rigged at wrong angle (too horizontal in heavy loading, too vertical in light loading).
• Inadequate lighting.

Heading and track control (Regulation 24)

Heading control (autopilot) and track control (autopilot with track-keeping function) systems may be used in accordance with the manufacturer’s recommendations, with the requirement that:

• The system must be capable of being overridden manually at any time.
• A return-to-manual control must be possible from any conning position.
• Watchkeeping must continue when the autopilot is engaged.
• In restricted waters, the master must consider whether to disengage the autopilot and use direct manual steering.

Modern autopilots include:

• Heading control mode: maintains a set heading.
• Track control mode: follows a planned route from waypoint to waypoint, integrating with ECDIS.
• Alarm-on-deviation: alerts the watch if the ship deviates from the planned track beyond a set tolerance.
• Auto-pilot fallback: automatically reverts to heading-only control if track-control inputs fail.

The Reg V/24 heading and track control calculator confirms the operational restrictions.

Operation of main source of power and steering gear (Regulations 25 to 26)

Regulation 25 requires that the main source of electrical power be operated under conditions of restricted manoeuvrability (port approaches, traffic-separation schemes, restricted visibility) so that loss of one generator does not result in propulsion failure. The typical practice is to bring all main generators online and to switch off non-essential consumers during such periods.

Regulation 26 imposes pre-departure testing of the steering gear: the master must satisfy himself that the steering gear has been tested within 12 hours before sailing, with all power units operated, alternative arrangements engaged, communication tested, and the rudder put through full range. Steering gear drills must be conducted at intervals of at least every three months, simulating loss of main steering and switching to alternative arrangement.

The Reg V/25 main source of power calculator and the Reg V/26 steering gear testing calculator cover the test schedules.

Nautical charts and publications (Regulation 27)

Every ship must carry adequate and up-to-date charts, sailing directions, lists of lights, notices to mariners, tide tables and all other nautical publications necessary for the intended voyage.

The “adequate and up-to-date” requirement was traditionally satisfied by paper charts kept current through Notice to Mariners (NM). On ships with mandatory ECDIS under Regulation 19, the requirement is satisfied by ECDIS using up-to-date Electronic Navigational Charts (ENCs), which are updated through chart correction broadcasts and overlays distributed via the IMO IHO standards.

T and P notices (Temporary and Preliminary Notices to Mariners) are critical for navigation in unfamiliar waters and must be plotted on the chart in use. The Notice to Mariners workflow is:

• Chart provider issues weekly NMs covering the coverage area.
• Master or navigation officer reviews NMs against the route.
• Charts in use are corrected by hand (paper) or by automatic update (ENC).
• The correction state is recorded in the chart correction record.

For voyages into waters where the master has limited familiarity, additional publications include sailing directions, port pilots’ books, and the relevant IALA buoyage information (IALA Region A in Europe, Africa, Middle East, Australasia; IALA Region B in the Americas, Korea and Philippines; the buoyage rules differ by region).

Records of navigational activities (Regulation 28)

Every ship must keep records of activities and incidents of importance to safety of navigation, including ship’s position, heading, course, speed, weather, sea conditions, navigation hazards observed, distress messages received, and engine and helm orders. The traditional record is the deck logbook; modern ships also maintain electronic logs and the VDR record.

Specific entries required include:

• Hourly positions and conditions during the voyage.
• Significant events: course changes, engine changes, pilot transfer, port arrival/departure.
• Weather observations.
• Hazards observed.
• Communications received.
• Crew changes during the voyage.
• Drills conducted.

The deck logbook is a legal document and is preserved for the ship’s life plus a number of years (typically 5 to 10) under flag state requirements.

Distress messages and obligations (Regulation 33)

Every master receiving a signal of distress is required to proceed with all speed to assist, unless excused. The signal can come from any source: GMDSS via Chapter IV (DSC, EPIRB activation, Inmarsat SafetyNET), visual signals (orange smoke, parachute flare, hand-held flare), audible signals (continuous fog horn signal, gun fire), AIS-SART activation, or by direct observation of a vessel in distress.

The master may be excused from rendering assistance if:

• He cannot reach the distress location.
• He is informed by the rescue coordination authority that other assistance is closer or more appropriate.
• He himself is in immediate danger or has already commenced rescue elsewhere.

In each case, the master must record the receipt of the distress and the reasoning for the action taken (or not taken) in the deck logbook. The Reg V/33 distress messages calculator walks through the procedural steps.

Safe navigation (Regulation 34) and misuse of distress signals (Regulation 35)

Regulation 34 requires the master to ensure that the voyage is planned in a way that avoids dangerous situations. The IMO Resolution A.893(21) on Voyage Planning provides the operational guidance, requiring the four-stage cycle:

• Appraisal: gather all information relevant to the voyage including charts, sailing directions, list of lights, port pilots’ books, weather forecast, tides, currents, NAVAREA warnings, ship-specific characteristics, regulatory requirements (TSS, reporting systems, Polar Code), and any operational constraints (cargo, crew, fuel range).
• Planning: prepare a detailed plan from berth to berth covering navigational hazards, contingency anchorages, and weather. The plan includes:
  • Route on chart with each leg’s course, distance, time, ETA at waypoint.
  • Safety-margin definitions: cross-track error tolerance, depth margin, distance from hazards.
  • Course-alteration positions with bearings, ranges to clear of hazards.
  • Contingency plans: what to do if weather changes, equipment fails, crew member becomes ill.
• Execution: the master and watch officers monitor progress against the plan and adjust as conditions change. Significant deviations are recorded.
• Monitoring: continuous comparison of actual position and progress against plan. The watch officer is responsible for monitoring; the master is responsible for major decisions.

The four-stage cycle is operationalised through the bridge resource management procedure and through the ISM Code Safety Management System.

Regulation 35 prohibits the misuse of distress signals, with criminal sanctions in most flag states for false distress alerts. False alerts have been a recurring issue in the GMDSS era because of unfamiliar test procedures on EPIRBs and AIS-SART; the IMO has issued guidelines for proper test procedures.

Notable casualties

MV Costa Concordia, 2012

The Italian-flagged passenger ship Costa Concordia struck a rock close inshore at Isola del Giglio after a deviation from the planned voyage track to perform an unauthorised salute manoeuvre. The casualty was a textbook failure of Regulation 34 (the salute manoeuvre had not been planned, briefed, charted or risk-assessed) and contributed to amendments tightening voyage planning under ISM Code and to bridge resource management under STCW.

The post-incident analysis identified:

• Voyage plan absence for the salute manoeuvre.
• Master’s autonomous decision-making without consultation.
• Crew failure to challenge the master’s decision.
• Inadequate ECDIS use (the rocks were charted but the shallow contour was below the safety setting).
• Bridge resource management failures.

MV Sewol, 2014

The South Korean ferry MV Sewol capsized after an excessively sharp helm input by an inexperienced helmsman in unfamiliar waters with poorly secured cargo. The casualty highlighted the navigational consequences of weak bridge resource management and contributed to international circulation of crew familiarisation standards.

MV Maritime Maisie, 2013 collision

The chemical tanker Maritime Maisie collided with the car carrier Gravity Highway off Korea and caught fire. The investigation found multiple Chapter V failures: navigational watch standards, AIS use, voyage planning. The case is widely cited in navigation training.

Container ship near-misses around Singapore Strait

The Singapore Strait, which carries one of the highest traffic densities in the world, regularly produces incidents and near-misses involving multiple ship-to-ship encounters. The IMO ship reporting system STRAITREP and the Strait Traffic Separation Scheme reflect the chapter’s reporting and routeing provisions; failures of those provisions are direct contributors to the casualty record.

Ever Given, 2021

The container ship Ever Given grounded in the Suez Canal on 23 March 2021, blocking the canal for six days. While not a navigational casualty in the conventional sense, the incident illustrated the operational fragility of dense traffic in narrow waterways. The post-incident analysis identified strong gusts and the ship’s bridge response timing as factors. The casualty is now a frequent reference in navigation simulator training.

MV Wakashio grounding, 2020

The bulk carrier MV Wakashio grounded on a reef off Mauritius on 25 July 2020, with subsequent oil spill of approximately 1,000 tonnes. The investigation found that the ship had altered course toward the reef to obtain better cellular signal for crew internet access; navigation watch was unable to recover before grounding. The casualty drove tightening of bridge resource management requirements and of cell-phone-on-bridge protocols.

E-navigation and the IMO Strategy

The IMO e-navigation Strategy (adopted 2008, with the implementation plan progressively rolled out from 2014) is a long-term initiative to improve safety of navigation through better integration of ship and shore systems. Key e-navigation deliverables that interact with Chapter V include:

• Maritime Service Portfolios (MSPs), defined service offerings provided by coastal authorities to ships, including pilotage, vessel traffic services, search and rescue, telemedical assistance, and ice information services. The MSPs standardise how shore-based services are described, accessed and integrated into ship navigation systems.
• S-100 universal hydrographic data model, the next-generation chart encoding standard, replacing S-57. S-100 supports richer data types (water levels, currents, weather, ice, environmental data) overlaid on the navigational chart, with content updated dynamically through the VHF Data Exchange System (VDES) and other communication paths.
• VTS (Vessel Traffic Service) integration, improvements in how VTS centres and ships exchange information, with standard messaging formats and automated response to advisories.
• Common Maritime Data Structure (CMDS), common syntax for maritime data, allowing ECDIS, AIS, radar, weather and chart systems to share data without proprietary translation.
• Cybersecurity provisions, guidance for ship-side cybersecurity following the 2017 IMO MSC.428(98) resolution requiring cyber risk management in the ISM Code.

The e-navigation strategy is not yet fully reflected in mandatory SOLAS provisions but is shaping the next generation of ECDIS, AIS and bridge integration. The 2018 amendments to Chapter V Regulation 19 added some forward-looking provisions for e-navigation equipment carriage.

IALA buoyage system

The IALA Maritime Buoyage System (International Association of Lighthouse Authorities) is the worldwide buoyage system used to mark navigable waters. The system is divided into two regions:

• IALA Region A (Europe, Africa, Middle East, Australasia, India): port-hand buoys are red, starboard-hand buoys are green.
• IALA Region B (Americas, Korea, Philippines, Japan): port-hand buoys are green, starboard-hand buoys are red.

The colour convention is the same in both regions for ship-to-buoy direction “going into harbour from open water”. The “red right returning” mnemonic in Region B contrasts with the “red left returning” pattern in Region A.

Both regions use a common set of additional marks:

• Cardinal marks: black-and-yellow buoys with topmark, indicating the direction (north, east, south, west) of safe water relative to the buoy.
• Isolated danger marks: black-and-red bands with topmark of two black spheres, indicating an isolated danger.
• Safe water marks: red-and-white vertical stripes, indicating safe water all around (used at landfall buoys).
• Special marks: yellow buoys, indicating special features (cable, pipeline, military exercise area, anchorage).

The IALA Maritime Buoyage System is referenced in voyage planning under Regulation 34 and is documented in nautical publications carried under Regulation 27.

Documentation and record-keeping

Every ship covered by Chapter V carries on board:

• Certificates of compliance with Chapter V (typically integrated into the Cargo Ship Safety Equipment Certificate, the Cargo Ship Safety Radio Certificate, or the Passenger Ship Safety Certificate).
• Up-to-date charts and publications (paper or ENC).
• Deck logbook and engine logbook.
• VDR records (live in capsule, plus on-board archive).
• Magnetic compass deviation card and adjustment certificate.
• Records of pilot transfer drills and steering gear tests.
• Voyage planning records (the route plans for past voyages, retained per ISM Code requirements).
• BNWAS test records.
• AIS, ECDIS, GPS, radar test and calibration records.
• LRIT test records.

Related Calculators

• SOLAS V/2, Definitions (navigation) Calculator
• SOLAS V/14, Manning Calculator
• SOLAS V/15, Bridge design principles Calculator
• SOLAS V/18, Approval, survey, performance of nav equipment Calculator
• SOLAS V/19, Carriage requirements Calculator
• SOLAS V/20, VDR Calculator
• SOLAS V/21, International Code of Signals Calculator
• SOLAS V/22, Navigation bridge visibility Calculator
• SOLAS V/23, Pilot transfer arrangement Calculator
• SOLAS V/24, Use of heading control or track Calculator
• SOLAS V/25, Operation of main source Calculator
• SOLAS V/26 (Steering gear) tests & drills Calculator
• SOLAS V/33, Distress alerts and MSS Calculator
• VDR, Recording Duration Calculator
• BNWAS, Dormancy-Alert Timing Calculator
• Wheelhouse, Forward Visibility Calculator
• GMDSS, Sea Area Coverage Check Calculator
• Pilot Ladder, Angle & Deployment Height Calculator

See also

• SOLAS Convention parent article
• SOLAS Chapter II-1: Construction, Subdivision, Stability, Machinery and Electrical Installations
• SOLAS Chapter II-2: Fire Protection, Detection and Extinction
• SOLAS Chapter III: Life-Saving Appliances and Arrangements
• SOLAS Chapter VI: Carriage of Cargoes and Oil Fuels
• GMDSS Overview
• AIS and ECDIS
• COLREGs Convention
• STCW Convention
• Just-in-Time Arrival
• Weather Routing
• Polar Code
• ISM Code
• Strait of Malacca
• Suez Canal
• Panama Canal

Additional calculators:

• ISM - SMS Gap-Analysis Score
• System - Radar - S-band: Long-range
• System - VDR / S-VDR: Voyage data recorder

Additional formula references:

• System Radar S Band Long Range
• System Vdr S Vdr Voyage Data Recorder
• System Bnwas Watch Alarm
• System Magnetic Compass Class Ii

Additional related wiki articles:

• COLREGs Steering and Sailing Rules: Rules 4 to 19

References

• IMO, International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, Chapter V.
• IMO Resolution A.1045(27), Recommendations on Pilot Transfer Arrangements.
• IMO Resolution A.893(21), Guidelines for Voyage Planning.
• IMO Resolution MSC.252(83) and amendments, Guidelines for Bridge Equipment and Performance Standards.
• IMO Resolution MSC.302(87), Performance standards for Class A AIS.
• IMO Resolution MSC.232(82), Performance standards for ECDIS.
• IMO MSC/Circ.982 and successor circulars on Bridge Resource Management.
• IMO MSC.1/Circ.1503 and successor circulars on ECDIS guidance.
• IHO S-57 and S-100 standards for ENC encoding.
• IALA Maritime Buoyage System.
• IAMSAR Manual, Volumes I, II, and III.
• International Code of Signals.