COLREGs Sound and Light Signals: Rules 32 to 37

Background

Purpose of sound and light signals

The Sound and Light Signals serve multiple purposes:

• Communicating intent: signalling planned manoeuvres before execution.
• Warning: alerting other vessels to imminent danger or doubt about another’s intentions.
• Identification in fog: providing audible identification when visual identification is impossible.
• Distress: signalling need for assistance.
• Attention: drawing attention when other signals are inadequate.

The audible communication system is essential because sound carries through fog, darkness, and over distances where visual identification may be limited or unreliable.

Sound signal architecture

The COLREGs sound signal architecture distinguishes:

• Manoeuvring signals (Rule 34): short and prolonged blasts indicating planned actions.
• Fog signals (Rule 35): prolonged blasts identifying vessel type in restricted visibility.
• Warning signals (Rule 34d): rapid blasts indicating doubt or danger.
• Attention signals (Rule 36): any signal that cannot be mistaken for another.
• Distress signals (Rule 37): incorporating Annex IV distress signal list.

The architecture provides distinct meanings for distinct situations.

Major amendment history

The Sound and Light Signals have been refined through COLREG amendment cycles:

• 1981: clarification of certain Rule 35 provisions.
• 1989: WIG craft additions.
• 2001: Rule 32 whistle frequency table refinement.
• 2007: minor refinements to align with technology.

The amendment cycle has been measured because sound signals are fundamental and ingrained in mariner training.

Rule 32: Definitions of signal devices

Whistle

The whistle is the primary sound signal device. Specifications:

• Sound type: continuous tone of audible quality (not a discontinuous “horn” but a sustained note).
• Fundamental frequency depending on vessel length:
  • Vessels of 200 metres or more: 70 to 200 Hz.
  • Vessels of 75 to 200 metres: 130 to 350 Hz.
  • Vessels of less than 75 metres: 250 to 700 Hz.
• Sound pressure level: minimum specifications by vessel size, ensuring audibility at defined ranges.
• Audibility range: minimum 2 nautical miles at 1/3 octave band level for the largest vessels; less for smaller.
• Type approval: required under MED, USCG, or other recognised authority.

The frequency variation by vessel size is to ensure that small vessels’ whistles do not sound similar to large vessels’ (avoiding misidentification).

Bell

The bell is supplementary, used primarily by anchored vessels and aground vessels:

• Sound: ringing of a metallic bell.
• Specifications: at least 30 cm diameter for vessels of 20 metres or more.
• Sound level: audible at defined range.
• Material: metal, with corrosion resistance for marine environment.

Gong

The gong is additional for vessels of 100 metres or more at anchor or aground:

• Sound: distinct from bell sound (typically lower pitch).
• Position: at the after part of the vessel for anchor/aground signals.
• Used in conjunction with: forward bell for the larger vessel anchored signal.

Rule 33: Equipment for sound signals

Sound signal equipment requirements:

• Vessels of 12 metres or more: whistle and bell required.
• Vessels of 100 metres or more: whistle, bell, and gong required (with separation between bell forward and gong aft).
• Vessels of less than 12 metres: whistle and bell not mandatory if alternative means of making efficient sound signal are available (e.g., hand-held horn).
• Vessels of less than 7 metres: same alternative provision.

The equipment scaling reflects that smaller vessels have different signal needs and may use simpler devices.

Rule 34: Manoeuvring and warning signals

Manoeuvring signals (Rule 34a)

When in sight of another vessel, a power-driven vessel underway makes the following signals when manoeuvring:

• One short blast (approximately 1 second): “I am altering my course to starboard.”
• Two short blasts: “I am altering my course to port.”
• Three short blasts: “I am operating astern propulsion.”

These signals support the COLREG Steering and Sailing Rules by communicating intent to nearby vessels. Compliance is mandatory in head-on, crossing, and overtaking situations.

Light signal supplement (Rule 34b)

The manoeuvring signals may be supplemented by light signals:

• One flash: “I am altering to starboard.”
• Two flashes: “I am altering to port.”
• Three flashes: “I am operating astern propulsion.”

The light is an all-round white light, repeated as appropriate. The minimum interval between flashes is approximately 1 second. The light signal supports the sound signal in conditions where sound is poorly audible (high background noise, distance).

The manoeuvring and warning signals calculator implements the Rule 34 lookup.

Narrow channel overtaking signals (Rule 34c)

In narrow channels, overtaking requires specific signals:

• Overtaking on the starboard side: two prolonged blasts followed by one short blast.
• Overtaking on the port side: two prolonged blasts followed by two short blasts.
• Vessel being overtaken agrees: one prolonged-one short-one prolonged-one short (“morse C” pattern).
• Vessel being overtaken doubts: five short blasts (Rule 34d warning signal).

The overtaking exchange formalises the agreement to overtake and is mandatory in narrow channels under Rule 9.

Warning signal (Rule 34d)

When vessels in sight of one another approach close to each other, with one vessel uncertain of the actions of the other, the doubting vessel sounds:

• Five or more short and rapid blasts.

This signal indicates “I am in doubt of your intentions” and demands clarification. It is one of the most-cited Rule 34 signals in casualty investigations.

The signal may be supplemented by five or more short and rapid all-round white light flashes.

Bend approach signal (Rule 34e)

A vessel approaching a bend or area of channel where another vessel may be obscured:

• One prolonged blast.

Other vessels approaching the same bend respond with a similar signal if able. The exchange supports awareness of vessel proximity in confined waters.

Rule 35: Sound signals in restricted visibility

Power-driven vessel making way

A power-driven vessel making way through the water sounds:

• One prolonged blast (4 to 6 seconds duration) at intervals of not more than 2 minutes.

The signal identifies a power-driven vessel that is moving, allowing other vessels to assess relative motion.

Power-driven vessel underway but stopped

A power-driven vessel underway but stopped (engines stopped, no way through water) sounds:

• Two prolonged blasts with about 2 seconds interval, at intervals of not more than 2 minutes.

The signal distinguishes a stopped power-driven vessel from a moving one.

Sailing, fishing, towing, RAM, NUC vessels

A vessel that is:

• Sailing
• Fishing
• Engaged in towing
• Restricted in ability to manoeuvre (RAM)
• Not under command (NUC)

sounds, when underway:

• One prolonged blast plus two short blasts at intervals of not more than 2 minutes.

The signal identifies the vessel as one with reduced manoeuvrability (corresponding to those with priority under Rule 18).

Vessel towed

A vessel being towed (or, if more than one, the last vessel of the tow) sounds:

• One prolonged blast plus three short blasts at intervals of not more than 2 minutes.

The signal identifies the towed vessel and supports the recognition that the towing combination is ahead.

Anchored vessels

A vessel at anchor sounds:

• Bell ringing rapidly for about 5 seconds at intervals of not more than 1 minute.
• For vessels of 100 metres or more: gong sounded immediately after the bell at the aft end of the vessel.

The bell forward / gong aft pattern allows nearby vessels to identify both ends of a long anchored vessel.

In addition, the anchored vessel may sound three blasts in succession (one short, one prolonged, one short) to give warning of position to an approaching vessel.

Aground vessels

A vessel aground sounds:

• Three bell strokes, then rapid bell ringing, then three bell strokes at intervals of not more than 1 minute.
• For vessels of 100 metres or more: gong sounded after the bell.
• In addition, the aground vessel may sound an appropriate whistle signal.

The pattern distinguishes aground from anchored vessels.

Pilot vessels

A pilot vessel on duty in restricted visibility sounds:

• The signal appropriate to her status (e.g., one prolonged blast if making way) PLUS
• Four short blasts as identification.

The four-short-blast addition supplements the standard signal with pilot identification.

The fog signal pattern lookup calculator implements the Rule 35 patterns by vessel type and status.

Rule 36: Signals to attract attention

If necessary to attract the attention of another vessel, any vessel may make light or sound signals that cannot be mistaken for any signal authorised elsewhere in the COLREGs, or may direct the beam of her searchlight in the direction of the danger, in such a way as not to embarrass any vessel.

Examples:

• Spotlight or searchlight beam: directing toward an unseen hazard.
• Air horn or siren: continuous or unusual pattern.
• VHF voice call: “Vessel approaching from north-east, this is…” identifying the calling vessel.
• Radar contact alert: “Vessel at bearing 045 from me, range 3 miles, do you see me?”

Rule 36 is a flexible provision allowing imaginative signalling when standard signals are inadequate. It is widely used in commercial practice as a supplement to standard signals.

Rule 37: Distress signals

Rule 37 incorporates by reference Annex IV of the COLREGs, listing distress signals:

Annex IV distress signals

• A gun or other explosive signal at intervals of about a minute.
• A continuous sounding with any fog-signalling apparatus.
• Rockets or shells throwing red stars fired one at a time at short intervals.
• A signal made by radiotelegraphy or by any other signalling method consisting of the group “…—…” (SOS) in Morse Code.
• A signal sent by radiotelephony consisting of the spoken word “MAYDAY”.
• The International Code Signal of distress indicated by N.C.
• A signal consisting of a square flag having above or below it a ball or anything resembling a ball.
• Flames on the vessel (such as from a burning tar barrel, oil barrel, etc.).
• A rocket parachute flare or a hand flare showing a red light.
• A smoke signal giving off orange-coloured smoke.
• Slowly and repeatedly raising and lowering arms outstretched to each side.
• A distress alert by means of digital selective calling (DSC) transmitted on:
  • VHF channel 70.
  • MF/HF on the frequencies for distress alerting.
• A ship-to-shore distress alert transmitted by the ship’s Inmarsat or other mobile satellite service.
• Signals transmitted by emergency position-indicating radio beacons (EPIRBs).
• Approved signals transmitted by radiocommunication systems including survival craft radar transponders (SARTs).

Distress signal use restrictions

Distress signals are subject to:

• Use only in actual distress (Rule 37 prohibits misuse).
• Reporting if false alert: incorrect distress alerts must be cancelled and reported.
• Penalties for misuse: criminal sanctions in most flag states under domestic law.

The distress signal system is the foundation for GMDSS emergency response.

Distress signal evolution

The distress signal list reflects historical development:

• Visual signals (flags, flares, smoke): pre-radio era.
• Sound signals (gun, fog horn): pre-radio era.
• Radio signals (MAYDAY, SOS): 20th century.
• Satellite signals (EPIRB, Inmarsat): late 20th century.
• AIS signals (AIS-SART): 21st century.

The list continues to evolve as new technology enables additional distress signalling.

Specific operational scenarios

Crossing situations with manoeuvring signals

In crossing situations:

• Give-way vessel may use Rule 34 signals to indicate planned alteration:
  • One short blast for altering to starboard (the typical Rule 8 action).
  • Sound signal not strictly required if visual contact is reliable.
• Stand-on vessel may use:
  • Five short blasts (Rule 34d) if doubt about give-way vessel intentions.

Overtaking with sound signals

In overtaking:

• Open water: sound signals not strictly required but may be used per Rule 34a if alteration involved.
• Narrow channel: Rule 34c sound exchange mandatory before overtaking.
• Passing on starboard: two prolonged plus one short.
• Passing on port: two prolonged plus two short.
• Agreement: one prolonged-one short-one prolonged-one short.

Restricted visibility encounters

In restricted visibility:

• Both vessels sound their respective Rule 35 fog signals.
• Mutual identification through fog signals supports situational awareness.
• Action under Rule 19 considers the fog signals heard.
• VHF communication typically used for confirmation when AIS or radar identify the target.

Approaching unseen vessels

When approaching unseen vessels (around a bend, in fog, etc.):

• Bend signal (Rule 34e): one prolonged blast.
• Fog signal (Rule 35): as appropriate to status.
• Warning signal (Rule 34d): if doubt arises during approach.
• VHF communication: for clarification.

Sound signal equipment

Whistle types

Modern ship whistles:

• Air-powered whistles: most common on commercial vessels, with compressor-driven air supply.
• Electric whistles: increasingly common on smaller vessels and as backup.
• Combination units: with manual and automatic operation modes.
• Audibility verification: at type approval and at periodic surveys.

Bell and gong

Bell and gong on commercial ships:

• Mounted forward and aft as appropriate to vessel size.
• Manual and electric striker options.
• Material: bronze or other corrosion-resistant alloy.
• Size and weight: meeting Rule 33 specifications.

Type approval

Sound signal equipment requires type approval:

• MED (Marine Equipment Directive) in EU waters.
• USCG for US-flag vessels.
• Class society approvals under various flag states.

The type approval ensures the equipment meets sound pressure level, frequency, and durability requirements.

Sound signal training

STCW provisions

Crew training under STCW:

• Section A-II/1, A-II/2: officers in charge of navigational watch must demonstrate competence in sound signal recognition and use.
• Section A-VIII/2: bridge resource management includes sound signal communication.
• Specific training: identifying sound signals and applying corresponding Rules 8, 18, 19.

Practical training

Practical training methods:

• Simulator-based: bridge simulators with realistic sound and visual scenarios.
• At-sea training: during actual encounters.
• Mock encounters: through coordinated training scenarios.
• Quiz and certification: periodic verification.

Specific operational considerations

Bridge fog procedure

Bridge fog procedure typically includes:

• Pre-fog briefing: covering Rule 19 obligations and Rule 35 signals.
• Speed reduction: to safe under prevailing conditions.
• Fog signal initiation: as soon as restricted visibility is encountered.
• Engines ready: for immediate manoeuvre.
• Heightened lookout: with all available means.
• VHF watch: on Channel 16 plus traffic-area channels.

Emergency response

Emergency response sound signals:

• General emergency alarm (Rule 37 derived): seven or more short blasts followed by one long blast.
• Abandon ship alarm: typically 7 short and 1 long blast on whistle and general alarm bell.
• Fire alarm: continuous ringing of general alarm.

The emergency signals are standardised under SOLAS Chapter III and the LSA Code.

Sound signals on smaller craft

Pleasure craft and small commercial

Sound signal arrangements for smaller craft:

• Vessels under 12 m: whistle and bell not strictly required (Rule 33), but alternative means must be available.
• Hand-held compressed-air horn: typical alternative for small vessels.
• Whistle (mouth-blown): minimum capability for very small craft.
• Voice signals: can supplement when very close.

Limitations of small craft signals

Small craft signal limitations:

• Reduced audibility range: typically 0.5 nautical miles or less.
• Susceptibility to wind and ambient noise.
• Reliance on visual observation in good visibility.
• VHF radio: increasingly common as supplementary communication.

Compliance for small craft

Small craft compliance:

• Documentation: smaller administrative burden than commercial vessels.
• Inspection: typically dockside or coastal inspection by harbour or coastguard authorities.
• Self-certification: in many jurisdictions for non-commercial pleasure craft, with the operator responsible for ensuring functional signal capability.
• Commercial operation: requires more rigorous compliance similar to larger vessels, with type-approved equipment and documented maintenance.
• Charter and rental craft: typically require commercial-grade compliance even when used for recreational purposes.
• International voyages: pleasure craft on international voyages must meet COLREG standards comparable to commercial vessels of similar size, with appropriate documentation and operational discipline.

Annex IV distress signals in detail

Visual distress signals

Visual distress signals from Annex IV:

• Parachute flares: red parachute-suspended flare, burning approximately 40 seconds, descending slowly to give time for observation; visible up to 30 nautical miles in good visibility.
• Hand-held flares: red hand-held flare burning approximately 60 seconds; visible at shorter range, used at close-quarters or when SAR resources are nearby.
• Buoyant smoke signals: orange smoke for daytime visibility; activate by water immersion or manual pull, lasting several minutes.
• Square flag with ball: black square flag with black ball above or below.
• Code signal NC: International Code of Signals letter “N” over “C” indicating distress.

Audible distress signals

Audible distress signals from Annex IV:

• Continuous fog horn: sustained signal indicating distress.
• Sustained gun fire: at intervals of about 1 minute (historic, rarely used).
• Bell ringing continuously: as supplementary distress signal.

Radio distress signals

Radio distress signals (the modern primary):

• VHF DSC distress alert on Channel 70.
• MF DSC distress alert on 2187.5 kHz.
• HF DSC distress alert on multiple frequencies.
• MAYDAY voice transmission on Channel 16 VHF or 2182 kHz MF.
• Inmarsat distress alert through dedicated terminal function.
• Iridium distress alert through Iridium-recognised devices.
• EPIRB activation: 406 MHz to Cospas-Sarsat satellite system.
• AIS-SART activation: AIS-based distress signalling.

The radio distress signals are integrated with the GMDSS regulatory framework under SOLAS Chapter IV.

Hand-held arm signals

The arm signals from Annex IV: slowly and repeatedly raising and lowering arms outstretched to each side. This signal is for use when other signals are not available and indicates need for assistance.

Distress alert response

When any vessel observes or receives a distress alert, the master is obliged to proceed with all speed to provide rescue assistance, as required by SOLAS Chapter V Regulation 33, unless excused.

Whistle technical specifications

Frequency table

COLREG Annex III Section 1 specifies the fundamental frequency range by vessel length:

The sound pressure level is measured at 1 metre from the whistle. The audibility range is the distance at which the whistle can be heard at 90 percent probability under reasonable atmospheric conditions and modest ambient noise.

Directionality

Whistle directionality:

• Forward-facing horns: limited to forward sound projection.
• Omnidirectional bells: 360-degree sound radiation.
• Multiple horns: some ships have multiple whistles for redundancy and improved coverage.

The directionality affects how vessels approaching from different bearings perceive the signal.

Acoustic characteristics

Whistle acoustic characteristics:

• Steady tone: smooth, sustained note (not modulated).
• Distinct from siren: not the rising-falling pattern of an emergency siren.
• Sound pressure stable: not pulsating.
• Quality: clear, recognisable as a ship’s whistle rather than other sound sources.

Power requirements

Sound signal device power requirements:

• Air pressure: typically 7 to 10 bar for compressed air whistles.
• Air consumption: substantial during a single blast (cubic metres of compressed air per blast).
• Electric power: alternative or backup electric whistles.
• Mechanical strikers: for bell and gong, with electric or pneumatic actuation.

The power infrastructure is part of the bridge automation and emergency power supply.

Sound signals in narrow channels

Specific narrow channel signals

Narrow channel signals under Rule 34c are particularly important:

• Approaching from astern wishing to overtake: two prolonged + one short or two short.
• Vessel ahead agreeing: one prolonged-one short-one prolonged-one short (“morse C”).
• Vessel ahead doubting/refusing: five short blasts (Rule 34d).

The signal exchange is a formal communication that must be heard and understood by both vessels before overtaking proceeds.

Major narrow channel applications

Specific narrow channels where Rule 34c is critical:

• Suez Canal transit: northbound and southbound convoys with potential overtaking.
• Panama Canal approaches and lock approaches: multiple overtaking situations.
• Strait of Bonifacio: with specific local rules supplementing.
• Singapore Strait approaches: high traffic density.
• English Channel narrow waters.
• River pilotage: many rivers with overtaking challenges.

Pilotage and sound signals

Pilots in narrow channel pilotage:

• Local knowledge of typical traffic patterns.
• Sound signal coordination with other pilots through VHF.
• Hand signals to bridge crew supplementing sound communication with the bridge.
• Documentation: pilot’s actions documented in pilot card and ship’s log.

Sound signal training under STCW

Knowledge requirements

STCW Section A-II/1 (officer in charge of navigational watch on ships of 500 GT or more) requires demonstrated knowledge of:

• COLREGs in detail: including all Rules including 32-37.
• Application to encounter situations: identifying the correct signals.
• Interpretation of received signals: understanding what other vessels are signalling.
• Sound signal equipment: operation and maintenance.

Practical skill demonstration

Practical skill demonstration includes:

• Simulator-based scenarios: demonstrating signal initiation in various situations.
• Hands-on equipment operation: actual whistle, bell, gong operation.
• Signal recognition: identifying signals played in audio scenarios.
• Casualty review: analysing past casualties for sound signal lessons.

Refresher training

Refresher training:

• STCW certificate validity of 5 years requires demonstration of continued competence.
• Operator-specific training for company-particular procedures.
• Post-incident training following any casualty involving sound signal issues.

Sound signal challenges in modern shipping

Background noise environments

Modern shipping environments present sound signal challenges:

• Container ship deck noise: refrigerated containers, ventilation, cargo handling create background noise.
• Tanker pump room noise: substantial noise during cargo operations.
• Engine room: high noise levels making bridge sound recognition difficult.
• Galley and accommodation: passenger ships have crew in noisy environments.
• Shore-side noise: in port approaches, traffic and industrial noise add to background.

The background noise affects both signal generation (where the bridge may not hear ship’s own whistle clearly) and signal reception (other vessels’ signals may be drowned out). Bridge officers compensate through:

• Rotating between bridge wings for hearing position.
• Headphones in some bridge configurations.
• Visual confirmation through searchlights or other means when sound is uncertain.
• VHF voice communication as supplementary when sound signals are uncertain.

Whistle sound limitations

Whistle sound has physical limitations:

• Range degradation: inverse-square law applies; at 5 nm range, sound intensity is 25 times less than at 1 nm.
• Atmospheric absorption: sound absorption increases with frequency; high-pitch whistles travel less far than low-pitch.
• Wind effects: downwind range may be doubled compared with upwind.
• Temperature inversion: in fog with temperature inversion, sound may be channelled below or above the inversion layer.
• Wave noise: sea state above force 5 produces substantial wave noise that masks ship signals.

Modern technology supplementing sound signals

Modern technology supplements traditional sound signals:

• AIS messages: text messages can supplement sound signals for specific intentions.
• VHF communication: voice clarification of intent.
• Radar/AIS bridge alerts: identifying targets that may not have audibly identified themselves.
• Visual signals: searchlight, semaphore, code flags.

The combination provides redundant communication channels.

Sound signal compliance and PSC inspection

PSC inspection focus

PSC inspection of sound signals covers:

• Whistle operation: bridge test of the whistle.
• Bell and gong condition: visual and operational check.
• Type approval certificates: for installed equipment.
• Audibility verification: from defined positions.
• Crew familiarity: through interview.
• Spare parts: for bell strikers and other consumables.

Common deficiencies

Common Annex V deficiencies include:

• Whistle inoperative: low air pressure, valve failure, electrical failure.
• Bell or gong missing or damaged: especially on older vessels.
• Type approval expired: for installed equipment.
• Audibility below specification: degraded over time.
• Crew unfamiliar with manual operation: for backup signal generation.

A serious sound signal deficiency can result in detention, especially if the vessel is operating in restricted visibility.

Sound signals in casualty investigation

Investigation focus

Casualty investigations frequently consider sound signals:

• Were appropriate signals sounded?: verified through bridge audio recording (VDR).
• Were signals heard by other vessels?: verified through VHF transcripts and other vessels’ VDR.
• Were Rule 34d warnings sounded?: when doubt about other vessel intentions arose.
• Were Rule 35 fog signals maintained?: at correct intervals.

The VDR audio recording (mandatory under SOLAS V/20) is the principal evidence.

Common findings

Common casualty investigation findings:

• Failure to sound Rule 34 manoeuvring signals during alterations.
• Inadequate Rule 35 fog signals, wrong pattern, wrong interval, omitted entirely.
• Failure to respond to Rule 34d warning signal: stand-on vessel not signalling doubt despite uncertainty.
• Confusion between manoeuvring signals: especially between one and two short blasts under stress.

The investigations have driven training emphasis on sound signal proficiency.

Sound signal evolution and future

Historical evolution

Sound signal evolution:

• Pre-1850: bell as primary signal; whistles emerging.
• Late 19th century: standardised steam whistles on commercial vessels.
• 20th century: air-driven whistles, electric backup.
• 21st century: modern integrated bridge systems with automatic signal generation.

Future evolution

Future sound signal evolution likely includes:

• Automated signal generation: AIS-triggered automatic Rule 34 signals during specific manoeuvres.
• Multi-frequency whistles: combining low and high frequency for better audibility in different conditions.
• Digital sound signal systems: solid-state generators replacing air-driven systems.
• Quieter whistles: reducing noise pollution while maintaining required audibility.
• MASS adaptations: for autonomous ships, sound signal generation may need new approaches.

MASS sound signal questions

For Maritime Autonomous Surface Ships:

• Who initiates signals?: with no human officer on board.
• Pattern recognition: AI/ML systems decoding incoming sound signals.
• Compliance verification: how to prove signals were sounded correctly.
• Failure response: when sound signal generation fails.

The IMO MASS regulatory framework will progressively address these questions.

Specific scenarios

Tanker cargo operations

During cargo operations:

• Signal generation may be suspended for specific times to avoid disturbing operations.
• Anchored tanker under cargo: anchor signals plus possibly RAM signals.
• Berthed tanker: typically not making signals at the berth.

Cruise ship operations

Cruise ships present specific considerations:

• Reducing noise for passenger comfort while maintaining COLREG compliance.
• Multiple horns: many cruise ships have ceremonial or musical horns in addition to navigation whistles.
• Departure ceremonies: cruise tradition of horn salutes; must comply with Rule 34/35.

Pleasure craft

Pleasure craft (under 12 metres):

• Reduced equipment requirements under Rule 33.
• Hand-held whistles acceptable.
• Compliance verification through enforcement at docks and on-water inspection.

Documentation

Every vessel maintains:

• COLREG copy with current amendments on board.
• Signal device specifications in the ship’s manual.
• Type approval certificates.
• Crew training records.
• PSC inspection records.

Related Calculators

• COLREG - Fog signal pattern lookup Calculator
• COLREG - Manoeuvring and warning signals (Rule 34) Calculator

See also

• COLREGs Convention parent article
• COLREGs Steering and Sailing Rules: Rules 4 to 19
• COLREGs Lights and Shapes: Rules 20 to 31
• SOLAS Chapter IV: Radio Communications and the GMDSS
• SOLAS Chapter III: Life-Saving Appliances and Arrangements
• SOLAS Chapter V: Safety of Navigation

Additional calculators:

• COLREG - Navigation Light Visibility Range
• COLREG - Vessel Identification by Lights

References

• IMO, Convention on the International Regulations for Preventing Collisions at Sea (COLREG), 1972, as amended.
• IMO COLREG Annex III (Technical details of sound signal appliances).
• IMO COLREG Annex IV (Distress signals).
• ICS Bridge Procedures Guide.