5. Introduction to Navigational Functions 

• Navigation has to be carried out correctly and safely, not to bring your own ship into danger, but also other ships at sea. 

• No risks should be taken. 

• Preventing by recognition, rectification and avoidance by all personnel of unsafe actions and/or situations, at all times and at all places on board is of utmost importance. 

• At all times, ships need to be navigated safely in compliance with the COLREGS and also to ensure that protection of the marine environment is not compromised. 

• An effective bridge organization should manage efficiently all the resources that are available to the bridge and promote good communication and teamwork.

• The need to maintain a proper look-out should determine the basic composition of  the navigational watch. There are, however, a number of circumstances and conditions that could influence at any time the actual watchkeeping arrangements and bridge manning levels. 

• Effective bridge resource and team management should eliminate the risk that an error on the part of one person could result in a dangerous situation. 

• The bridge organization should be properly supported by a clear navigation policy incorporating shipboard operational procedures, in accordance with the ship's Safety Management System as required by the ISM Code.

The Integrated Bridge 

Many vessels and virtually all new builds of all ship types are being constructed with the integrated navigational bridge.

The following equipment and controls fitted on the navigational bridge are; 

• Fire alarm 

• Fire detection system 

• Watertight door indicators 

• Navigation lights, ship’s whistle 

• Navigation shapes 

• Deck lights 

• Over side lights 

• Aldis lamp 

• BNWAS 

• Radars 

• Echo sounder 

• ROT indicator 

• Line throwing apparatus 

• Rudder angle indicator 

• MOB combined light/signal 

• LRIT 

• Steering gear in manual, auto pilot, NFU 

• Off course alarm and auto steering 

• Internal, external and portable communication 

• Gyro compass, repeaters, magnetic compass, azimuth circle 

• Engine telegraph 

• Flags 

• binocular, sextants, chronometer, etc.

Steering system (Auto pilot, manual hand steering, Emergency steering and wing controls 

The International Regulations for Preventing Collisions at Sea 1972 (COLREGs) are a set of rules to be followed while navigation of ship to avoid collisions at sea. 

It is one of the most important International Conventions that all Masters, navigational officers and watchkeeping personals must understand and be able to apply to real world situations. 

The COLREGs include 41 rules divided into six sections: 

• Part A - General;

• Part B - Steering and Sailing;

• Part C - Lights and Shapes;

• Part D - Sound and Light signals;

• Part E - Exemptions; and

• Part F - Verification of compliance with the provisions of the Convention.

There are also four Annexes containing technical requirements concerning lights and shapes and their positioning; sound signaling appliances; additional signals for fishing vessels when operating in close proximity, and international distress signals.

Rule 1 states that the rules apply to all vessels upon the high seas and all waters connected to the high seas and navigable by seagoing vessels. 

Rule 2 covers the responsibility of the master, owner and crew to comply with the rules. 

Rule 3 includes definitions of water craft. 

Section 1 - Conduct of vessels in any condition of visibility (Rules 4-10) 

Rule 4 says the section applies in any condition of visibility. 

Rule 5 requires that "every vessel shall at all times maintain a proper look-out by  sight and hearing. 

Rule 6 deals with safe speed. 

Rule 7 covering risk of collision, which warns that "assumptions shall not be made   on the basis of scanty information, especially scanty radar information." 

Rule 8 covers action to be taken to avoid collision. 

Rule 9 vessels proceeding in narrow channels should keep to starboard.

Rule 10 of the Regulations deals with the behaviour of vessels in or near traffic separation schemes. Ships crossing traffic lanes are required to do so "as nearly as practicable at right angles to the general direction of traffic flow."

Section II - Conduct of vessels in sight of one another (Rules 11-18) 

Rule 11 says the section applies to vessels in sight of one another. 

Rule 12 states action to be taken when two sailing vessels are approaching one another. 

Rule 13 covers overtaking - the overtaking vessel should keep out of the way of the vessel being overtaken. 

Rule 14 deals with head-on situations. 

Rule 15 covers for Crossing situations 

Rule 16 deals with the action to be taken by the give-way vessel 

Rule 17 deals with the action of the stand-on vessel 

Rule 18 deals with responsibilities between vessels and includes requirements for vessels which shall keep out of the way of others.

Section III - conduct of vessels in restricted visibility (Rule 19) 

Rule 19 states every vessel should proceed at a safe speed adapted to prevailing circumstances and restricted visibility. A vessel detecting by radar another vessel should determine if there is risk of collision and if so take avoiding action. A vessel hearing fog signal of another vessel should reduce speed to a minimum.

Rule 20 states rules concerning lights apply from sunset to sunrise. 

Rule 21 gives definitions. 

Rule 22 covers visibility of lights - indicating that lights should be visible at minimum ranges (in nautical miles) determined according to the type of vessel. 

Rule 23 covers lights to be carried by power-driven vessels underway. 

Rule 24 covers lights for vessels towing and pushing. 

Rule 25 covers light requirements for sailing vessels underway and vessels under oars. 

Rule 26 covers light requirements for fishing vessels. 

Rule 27 covers light requirements for vessels not under command or restricted in their ability to manoeuvre. 

Rule 28 covers light requirements for vessels constrained by their draught. 

Rule 29 covers light requirements for pilot vessels. 

Rule 30 covers light requirements for vessels anchored and aground. 

Rule 31 covers light requirements for seaplanes.

Rule 32 gives definitions of whistle, short blast, and prolonged blast. 

Rule 33 says vessels 12 metres or more in length should carry a whistle and a bell and vessels 100 metres or more in length should carry in addition a gong. 

Rule 34 covers manoeuvring and warning signals, using whistle or lights. 

Rule 35 covers sound signals to be used in restricted visibility. 

Rule 36 covers signals to be used to attract attention. 

Rule 37 covers distress signals.

Rule 38 says ships which comply with the 1960 Collision Regulations and were built or already under construction when the 1972 Collision Regulations entered into force may be exempted from some requirements for light and sound signals for specified periods.

Rule 39 provides definitions. 

Rule 40 says that Contracting Parties shall use the provisions of the Code for Implementation in the execution of their obligations and responsibilities contained in the present Convention.

Rule 41 on Verification of compliance says that every Contracting Party is subject to periodic audits by the IMO. 

Annex I - Positioning and technical details of lights and shapes 

Annex II - Additional signals for fishing vessels fishing in close proximity 

Annex III - Technical details of sounds signal appliances 

Annex IV - Distress signals, which lists the signals indicating distress and need of assistance.

Lights- As per COLREG72- Rules 21 and 22, Annex 1, Arcs and ranges of lights for power-driven vessel as shown in below figure. 

Shapes-As per Annex-I, Shapes shall be black and of the following sizes: 

(a) (i) a ball shall have a diameter of not less than 0.6 metre; 

(ii) a cone shall have a base diameter of not less than 0.6 metre and a height equal to its diameter; 

(iii) a cylinder shall have a diameter of at least 0.6 metre and a height of twice its diameter; 

 (iv) a diamond shape shall consist of two cones as defined in (ii) above having a common base. 

(b) The vertical distance between shapes shall be at least 1.5 metres. 

(c) In a vessel of less than 20 metres in length shapes of lesser dimensions but commensurate with the size of the vessel may be used and the distance apart may be correspondingly reduced.

Fog Signals- As per Rule 35, Use of Sound signals in restricted visibility are described as, 

In or near an area of restricted visibility, whether by day or night, the signals prescribed in this rule shall be used as follows: 

• A power-driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast. 

• A power-driven vessel underway but stopped and making no way through the water shall sound at intervals of not more than 2 minutes tow prolonged blast in succession with an interval of about 2 second between them. 

• A vessel not under command, a vessel restricted in her ability to manoeuvre, a vessel constrained by her draught, a sailing vessel, a vessel engaged in fishing and a vessel engaged in towing or pushing another vessel shall sound at intervals of not more than 2 minutes three blast in succession, namely one prolonged followed by two shout blasts.

Annex IV: distress signals 

1) The following signals, used or exhibited either together or separately indicate distress and need of assistance: 

(a) a gun or other explosive signal fired at intervals of about a minute; 

(b) a continuous sounding with any fog-signaling apparatus; 

(c) rockets or shells, throwing red stars fired one at a time at short intervals; 

(d) a signal made by radiotelegraphy or by any other signaling method consisting of the group … – – – … (SOS) in the Morse Code; 

(e) a signal sent by radiotelephony consisting of the spoken word ‘Mayday’; 

(f) the International Code Signal of distress indicated by N.C.; 

(g) a signal consisting of a square flag having above or below it a ball or anything resembling a ball; 

(h) flames on the vessel (as from a burning tar barrel, oil barrel, etc.); 

(i) a rocket parachute flare or a hand flare showing a red light; 

(j) a smoke signal giving off orange-coloured smoke; 

(k) slowly and repeatedly raising and lowering arms outstretched to each side; 

(l) the radiotelegraph alarm signal;

(m) the radiotelephone alarm signal; 

(n) signals transmitted by emergency position-indicating radio beacons; 

(o) approved signals transmitted by radio communication systems, including survival    craft radar responders. 

2) The use or exhibition of any of the foregoing signals except for the purpose of indicating distress and need of assistance and the use of other signals which may be confused with any of the above signals is prohibited. 

3) Attention is drawn to the relevant sections of the International Code of Signals, the Merchant Ship Search and Rescue Manual and the following signals: 

(a) a piece of orange-coloured canvas with either a black square and circle or other appropriate symbol (for identification from the air); 

(b) a dye marker.

When navigating in restricted visibility, high density of traffic or in a restricted area, the bridge team shall be composited by Master commanding on bridge, one OOW (if necessary two OOWs), two Deck Ratings (one of them assisting in lookout), hand steering. 

In this arrangement, can be carried for assisting in look out duty and navigational watch. In the passage of Piracy high risk areas, can also be assisted in anti-piracy watch as well as look out duty and navigational watch. 

As per COLREG 72- Rule 5 

Look-out 

Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision. 

Duty of look-out 

The look-out should report any lights, vessels or large floating objects which he sees, and, in low visibility, any fog signals which he hears. 

However, in crowded waters, he could not be expected to report everything he sees; he must use his discretion and report the lights or objects which are likely to bring risk of collision, especially small craft which may not have been observed from the bridge.

Principles of a Navigational Watch-keeping 

• continuous proper look-out as per Rule 5; 

• full appraisal of situation and risk of collision, stranding and other dangers to navigation; 

• detecting ships or aircraft in distress, survivors, debris and wrecks; 

• look-out man should not undertake other duties; 

• look-out and helmsman should be separate; 

• sole look-out should be in daylight only or situations safe to do so (visibility, traffic, TSS); 

• composition of navigational watch depends on weather, traffic, workload, fitness, skill and equipment facility, etc.

The lookout is obliged to give his full, uninterrupted attention to this duty, reporting any of the following to the Officer of the Watch: 

• All ships, irrespective of size or position in relation to the vessel on which the lookout is sailing. 

• All navigation marks or lights. 

• All floating objects. 

• Any sightings of ice, no matter in what form. 

• Sandbanks or prominent navigational features. 

• Derelicts and any other hazard considered dangerous to navigation. 

• The malfunction of the ship’s lights, and their correct functioning at hourly intervals.

The lookout is also obliged to remain at his or her position until correctly relieved of duties. On being relieved, the relief should be given any relevant information concerning the items reported. The lookout has a very responsible job and the duties must never be taken lightly.

Give the initial report when you first sight a contact. 

Usually, the contact is too far away for a positive identification, but do not delay the report. 

Include in the initial report: 

1. WHAT YOU SEE: Describe the contact quickly and briefly. Name the type or class of ship      or aircraft if you recognize it; otherwise, simply report “ship,” “plane,” and so forth. 

2. BEARING: Always report contacts in relative bearings. These are given as three digits, spoken digit by digit. 

3. RANGE: Ranges are reported in yards/miles and spoken digit by digit, except that   multiples of hundreds and thousands are spoken as such. 

4. TARGET ANGLE: Report target angle on all ships. It will be given in three digits, spoken digit by digit. 

5. POSITION ANGLE: Report position angle on all aircraft. It will be given in one or two digits, spoken as a whole, not digit by digit. 

6. MOVEMENT: Report whether the contact is moving from right to left, left to right, opening, closing, paralleling, high speed, slow speed, dead in the water, and so forth. 

In order to describe the position of ships in relation to the tanker, they can be used as follows: 

1. Ship A is (dead) ahead./Ship A is ahead of the tanker. 

2. Ship B is on the starboard bow. 

3. Ship C is before the starboard beam.

4. Ship D is abeam./Ship D is on the starboard beam. 

Forward lookout: Stationed as far forward and as close to the waterline as possible. Sector extends 30° on each side of the bow (330° - 030°). 

Starboard lookout: Stationed on the Starboard bridge wing. Sector extends from the Forward lookout's boundary to the starboard beam (030° - 090°). 

Aft lookout: Stationed as far aft and as close to the waterline as possible. Sector extends from the Starboard beam clockwise to the port beam (090 ° - 270°). 

Port lookout: Stationed on the port bridge Wing. Sector extends from the port bow to the forward Lookout's boundary (270° - 330°). 

During restricted-visibility conditions, conduct a moderately fast search without binoculars, but have them within reach in case the fog suddenly lifts. 

During restricted visibility, hearing sound signals will have to be reported by hearing prior to the actual sighting. Sounds that might be heard and must be reported are bell and whistle buoys, small craft motors, fog signals, wash of water on another ship's hull, and any other unusual sounds. You must constantly be alert and concentrate on the job at hand to hear these sounds. 

Report sound signals using the following format. 

1. WHAT IS HEARD: One prolonged blast, a rapid ringing bell, two short whistles, and so forth. 

2. WHERE YOU HEAR IT: Use relative bearings. Be as accurate as possible. 

3. SOUND STRENGTH: Weak, loud, or medium. 

4. INTENSITY: Sound getting stronger, weaker, or remaining the same. 

5. BEARING DRIFT: Sound is drifting from left to right, right to left, or remaining steady on same bearing.

The following is a sample of a sound signal report made by the forward lookout: 

ALL STATIONS—THIS IS FORWARD LOOKOUT—I HEAR TWO WEAK PROLONGED 

BLASTS—BEARING 015—WITH A RIGHT BEARING DRIFT. 

Other examples of reporting styles are;

1)  A ship, 2 points of starboard bow, Sir. 

2)  A ship, 2 points of starboard bow, no navigation lights. 

3)  A ship, 2 points of starboard bow, showing her green light. 

4)  A ship, 2 points of starboard bow, showing her red light. 

5)  A ship, 2 points of starboard bow, coming down 

6)  A light house, 4 points of starboard bow, showing her lights 

7)  A speed boat, 2 points 2 points of port quarter. 

8)  A ship port bow, coming down port to port. 

9)  One overtaking vessel, abaft, port quarter 2 points 

10)  There is a crossing vessel, 2 points of starboard bow 

11)  There is a ship with a side light, 2 points of starboard bow, that ship is now   crossing to port side 

12)  There is a ship with a green side light and 2 vertical all round red lights (NUC vessel) at right ahead 

13)  There is two fishing boat crossing 1 point of starboard bow to portside 

14)  Some debris, right ahead 

15)  It is horn signal, 2 points of starboard bow.

On anchoring, a fix on the anchor drop position should be made and the ship's swinging circle ascertained, based upon the length of cable in use. Landmarks and transits should be selected for ease of monitoring the position of the ship as it lies at anchor, and appropriate light and shape signals should be exhibited in accordance with the COLREGS and any local regulations. 

While at anchor, there should maintain a check on the ship's position to monitor that the ship does not drag its anchor or move too close to any other anchored ship. 

A proper look-out must be maintained and ship inspection rounds made periodically, particularly if the ship is anchored in waters which might present a risk of attack by pirates or armed robbers. 

The master/OOW should be notified immediately if the ship drags her anchor, or if sea conditions or visibility deteriorate. 

All deck ratings can be contributed to safe anchor watch keeping when required. 

• Plot the vessel's position on the largest scale chart available 

• Set anchor watch alarm on GPS / Radar Guard Zone 

• Frequently check the vessel's position using visual bearings, ranges or transits 

• Ensure proper lookout (including VHF watch) is maintained at all times 

• Ensure engines are available as specified by the master in case vessel starts to drag Anchor

• Necessary lights and shapes and sounding appropriate signal as required 

• Frequent security rounds made of the vessel and fire patrol maintained 

• Observe meteorological and tidal conditions 

• Pay particular attention to know anchor dragging of own ship and other ships especially when tidal turns. 

• Notify the master and take necessary action if vessel starts to drag anchor 

• Notify master if visibility deteriorates 

• Ensure ship is taking all measures to protect the environment from pollution from the Vessel

• Fire hazards, potential sources of fire 

• Security of ship including surrounding water 

• Watertight doors and assess doors 

• Trace of pollutions 

• Crew and persons onboard 

• Exhibition of light and shapes 

• Obvious sound and smell within onboard ship

• Any suspicious matter onboard

Knowledge of Flag signals 

Ships’ flags are normally stowed on the bridge or near the bridge area in an easily accessible flag locker. 

Flag halyards are normally stretched to port and starboard bridgewings and the monkey island from the triatic stay. 

Flags should be fitted with brass Inglefield clips, one of the clips being fitted with a swivel fitment. 

Halyards should be similarly fitted with the clips to facilitate speedy attachment of the hoist. 

Flag Signaling Terms 

At the Dip: This term is used to describe a signal which is hoisted to approximately half the extent of the halyard (often displayed as a mark of respect following a death). 

Close Up: This denotes that the flag hoist is flying at its maximum height, e.g. close up to the truck, at the mainmast. 

Signal Letters: These are letters allocated to vessels to signify the ‘call sign’ of that vessel for the purpose of communication and identification.

Tackline 

This is a length of halyard about one fathom in length, the tackline is used to separate two distinctive hoists on the same halyard. 

A =  I have a diver down; keep well clear at slow speed. 

B =  I am taking in, or discharging, or carrying dangerous goods. 

C =  Yes (affirmative or ‘The significance of the previous group should be read in the affirmative’). 

D =  Keep clear of me; I am manoeuvring with difficulty. 

E =  I am altering my course to starboard. 

F =  I am disabled; communicate with me. 

G =  I require a pilot. When made by fishing vessels operating in close proximity on the fishing grounds it means: ‘I am hauling nets.’ 

H =  I have a pilot on board. 

I =  I am altering my course to port. 

J =  I am on fire and have dangerous cargo on board: keep well clear of me. 

K =  I wish to communicate with you. 

L =  You should stop your vessel instantly. 

M =  My vessel is stopped and making no way through the water. 

N =  No (negative or ‘The significance of the previous group should be read in the negative’). 

This signal may be given only visually or by sound. For voice or radio transmission the  signal should be ‘No’. 

O =  Man overboard.

P =  In harbour: All persons should report on board as the vessel is about to proceed to sea. 

 At sea: It may be used by fishing vessels to mean: ‘My nets have come fast upon an obstruction.’ 

Q =  My vessel is ‘healthy’ and I request free pratique. 

S =  I am operating astern propulsion. 

T =  Keep clear of me; I am engaged in pair trawling. 

U =  You are running into danger. 

V =  I require assistance. 

W =  I require medical assistance.

X =  Stop carrying out your intentions and watch for my signals. 

Y =  I am dragging my anchor. 

Z =  I require a tug. When made by fishing vessels operating in close proximity on the fishing grounds it means: ‘I am shooting nets.’

The purpose of the three substitute flags is to enable a letter or numeral pendant to be repeated in the same hoist. A letter or number may have to be repeated more than once within the same hoist so there are three substitute flags, not just one. When a substitute flag is used, it refers only to the hoist in which it is contained. If the first substitute is used, it will mean a repeat of the first letter/numeral flag of the hoist. If the second substitute flag is used, it will mean that the second flag of the hoist, letter or numeral is repeated. The third substitute indicates that the third flag of the hoist is repeated.

Instructor made the following sound signals by using video and audio files; 

• General Alarm 

• Fire Alarm 

• Manoverboard Alarm 

• Abandon Ship Alarm 

• CO2 Alarm 

• Ship Security Alarm System 

• Oil spill (SOPEP) alarm (if assigned and defined separately) 

International Association of Lighthouse Authorities (IALA) attempted to provide the system which applies to all fixed or floating marks, other than lighthouses, sector lights, leading lights and marks, light vessels and lanbys. It serves to indicate the centrelines of channels and their sides, natural dangers such as sandbanks, as well as wrecks (described as new dangers when newly discovered), and also areas where navigation is subject to regulation. Each of the ‘A’ and ‘B’ systems comprises simplified lateral marks (port and starboard channel marks) and cardinal marks to be used in conjunction with the mariner’s compass. The shapes of buoys, of which there are five, are common to both systems: can, conical, spherical, pillar and spar.

Lateral marks are generally used for defining the navigable channel in and out of harbour. Port and starboard buoys are used in conjunction with the conventional direction of buoyage.