Chapter 3 ‐ PASSAGE PLANNING

Question 1

Dois estágios do planejamento

Answer 1

1 Ocean and open waters.
2 Coastal and estuarial waters.

Question 2

Utilização das cartas náuticas no planejamento

Answer 2

1 ‐ Seleção de todas aquelas que digam respeito à viagem;
2 - Inclusive de trechos próximos e de grande escala como portos;
2 - Colocá-las em ordem;
3 - Assegurar que elas estão atualizadas.

Collect together all the charts for the intended voyage, putting them into the correct order. Charts not absolutely necessary for the voyage but which are adjacent to the area to be traversed should he included, as should very large scale charts, e.g. port plans on the coastal part of the voyage. Although it may not be necessary to acrually use such charts, they may include information that will prove of use during the voyage. Ensure that all charts and publications
have been corrected to the latest Notice to Mariners available and
that any authentic Nav warnings etc. received from any source are
also included (see Annex Il). Similar corrections may also have to
be made during the voyage after the plan has been completed and
the plan having to be subsequently modified.

Question 3

No-go-areas

Answer 3

Coastal and estuarial charts should be examined, and all areas where the ship CANNOT go must be carefully shown by highlighting or cross hatching, care being taken to not obliterate information such as a navigation mark or a conspicuous object. Areas so marked are to be considered as no-go areas. In waters where the tidal range may not be very large, no-go areas will include all charted depths of less than the ship’s draught plus a safety margin. Such areas will vary according to the ship’s draught so will not necessarily be the
same for both inward and outward passages. In general the line determining “no-go” will be not less than draught + 10%, though
this will need to be modified according to the prevailing
circumstances. Draught + 10% may well prove adequate in areas
where the sea is smooth but will require a considerably higher figure
if the ship is liable to pitch, roll or squat.

In confined waters, where the tidal height may have a large influence, such no-go areas will vary according to the time of passage. Initially all areas and dangers showing charted depths of less than the draught plus the safety margin should be
considered no-go, though such no go areas may be subsequently amended when the actual time of passage is known. Such areas will need to be carefully marked showing the times and state of tide at which they are safe.

Question 4

No-go-areas sem variação de maré

Answer 4

No-go-areas serão aquelas que extrapolam o calado do navio acrescido de uma margem de segurança de 10%.

Por conta disso, haverá uma variação na saída ou entrada (inward and outward passages).

Também será necessária essaa margem mesmo que o mar seja calmo se o nvio estiver suscetível à pitch, roll ou squat.

Question 5

No-go-areas (áreas confinadas com forte corrente)

Answer 5

Tais áreas variarão de acordo com o momento da passagem.

Contudo, inicialmente, áreas com profundidade menor do que o calado do navio já devem ser consideradas como no-go-areas. Mas isso pode mudar de acordo com o horário da passagem, sendo necessário marcá-las, deixando claro o horário e o estado da maré.

Question 6

Margins of Safety

Answer 6

Em grandes navios, é possível que uma parte do navio já se encontre em uma área de perigo (no-go-areas) quando a sua posição for plotada. Por conta disso, é necessário estipular margens de segurança de forma que, na pior hipótese, a ponte de comano não passe por essas áreas.

Before tracks are marked on the chart the clearing distance from the no-go areas needs to be considered. When a fix is plotted on a chart it invariably represents the position of a certain part of the ship’s bridge at the time of the fix. With large ships, although the
plotted fix at a certain time may be outside a no-go area, it is possible
that another part of the ship may already be in it - with disastrous
results. A safety margin is required around the no-go areas at a
distance that, in the worst probable circumstances, the part of the
ship being navigated (the bridge) will not pass. On occasion, the
margins of safety can be readily monitored by eye, e.g. using buoys
marking the safe limits of a channel or easily identified clearing bearings.

Question 7

Fatores para determinar a margem de segurança

Answer 7

1 The dimensions of the ship.
2 The accuracy of the navigational systems to be used.
3 Tidal streams.
4 The manoeuvring characteristics of the ship.

Question 8

Importância da margem de segurança

Answer 8

A importância de se determinar as margens de segurança é, justamente, o seu monitoramento; isso se dá por meio da integração destes dados à um sistema de navegação.

The Margins of Safety should be chosen so that they can be readily monitored. To achieve this they need to be related to one of the navigation systems in use (e.g. clearing bearings related to a headmark or Parallel Indexes).

Question 9

Profundidade margem de segurança

Answer 9

Deve ser superior à medida do calado + 20%, podendo ser aumentada caso:

1. Quando as informações e os dados de vigilância são velhos ou incertos;
2. Em situações que o navio está balançando (roll) ou arfageando (pitch);
3. Quando o navio está sofrendo squat;
4. Quando o calado aumentar pelo navio ter passado em águas frescas.
5. When the survey is old or unreliable.
6. In situations where the ship is pitching or roning.
7. When there is a possibility that the ship may be experiencing squat
8. When the ship may have increased the draught by passing
   into fresh water.

Question 10

Safe water

Answer 10

Areas where the ship may safely deviate are considered to be Safe Water and the limits of this safe watcr arc bounded by the Margins of Safety.

Question 11

Ocean and open Water Tracks

Answer 11

Ocean and Open Water tracks should first be drawn on smallscale
charts, according to the decisions made at the appraisal stage regarding the route to be taken. Great circle and composite great circle tracks win have to be calculated or obtained from the GPS or from great circle charts. Rhumb lines may be drawn straight onto the Mercator chart, but all tracks will have to conform to the limits determined at the appraisal stage.

Question 12

Coastal and Estuarial Tracks

Answer 12

Primeiro se desenha a derrota em cartas náuticas de pequena escala, contendo a rota entre o porto de partida e chegada; talvez seja necessário utilizar-se de mais de uma carta náutica.

Esse esboço é utilizado para se determinar as distâncias, os tempos das marés e os tempos estimados de chegada (ETA).

Existem diversos fatores que podem mudar o curso do rumo, como o set and drift, leeway.

Posteriormente essa derrota deve ser transferida para uma carta de grande escala.

Coastal and Estuarial Tracks will also be constrained by the
decisions made at the appraisal stage and should be first drawn on
the small scale charts covering large portions of the coastline,
preferably from the departure port approaches to the arrival port.
This will depend upon proximity of the ports and the charts of the
area. 10 many cases more than one chart will have to be used. These
first tracks will fann the basis of the plan and from them may be
obtained distances and steaming times and when the departure time
is known, the ETAs at the various waypoints en route can be
established.
The true direction of the track should be shown close to the
track on the chart. This will not necessarily be the course steered to
make this track; it only indicates the direction to make good. The
course to steer will depend upon various factors at the time of making
the passage, e.g. tidal set and drift, leeway, etc.
When completed, these tracks should be transferred to and
drawn on the large-scale charts of the area to be traversed. Transfer
of a track from one chart to another must be done with great care.
To ensure that no mistakes are made, it is good practice to
double check this operation by using a range and bearing of the
transfer position from a readily identifiable object e.g. a light common
to both charts. This can be further confirmed on both charts by
checking the latitude and longitude of the transfer position.

Question 13

Chart Change

Answer 13

It should be quite clearly shown on a chart the position where it is required to transfer to the next chart, giving the next chart’s number.

Question 14

Track Consideration

Answer 14

Como regra geral, o navio precisa ficar em águas seguras. Caso seja necessário se aproximar de algum perigo, cuja única motivação é a redução do tempo da viagem, isso deve ser feito com cautela, mantendo o navio, o máximo possível, em águas seguras, de forma a inibir o encalhamento por problema de máquinas ou de navegação.

As a general rule there is nothing to be gained by closely
approaching a danger other than to reduce passage distance and
consequently, steaming time. When it does become necessary to
approach a danger there are general minimum rules that need to be
followed. The ship has always to remain in safe water (see page 19)
and keep suffiCiently far off a danger to minimise the possibility of
grounding in the event of a machinery breakdown or navigational
error.

Question 15

Distance off danger

Answer 15

Não existem regras prestabelecidas quanto à distância do perigo, que possam ser aplicadas de forma rápida e prática, já que elas dependem dos seguintes fatores:

1. O calado do navio em relação à profundidade;
2. As condições climáticas;
3. A direção e a intensidade da corrente;
4. O tráfego marítimo;
5. A qualidade das informações obtidas pelas cartas náuticas, que podem estar defasadas;
6. A possibilidade de se trafegar por áreas seguras.

O autor determina algumas distâncias préestabelecidas:

Navio de calado inferior à 3 metros - distância de no mínimo 5 metros;
Calado entre 3 e 6 metros - distância de 10 metros;
Calado entre 6 e 10 metros - distância de 20 metros;
Calado de mais de 10 metros - distância de 200 metros.

Question 16

Regulations

Answer 16

Owners’, charterers’ and national regulations regarding
offshore distances must also be obsetved.

Question 17

Situações de perigo e tráfego marítimo

Answer 17

É necessário deixar um espaço extra considerando que é possível que o rumo seja alterado em direção ao perigo por uma questão de tráfego.

Irrespective of the safe under·keel clearance, a ship in a
situation where the nearest navigational danger is to starboard must
allow sufficient distance to allow an adequate alteration of course to
starboard for traffic avoidance.

Question 18

Deviation from Track

Answer 18

Ideally the ship will follow the planned track but under certain circumstances it may be necessary to deviate from such track, e.g.
having to a1ter for another ship. Even so, such deviation from track
should be limited so that the ship does not enter areas where it may
be at risk or closely approaching the margins of safety

Question 19

Under-keel clearance (UKC)

Answer 19

A ponte de comando deve saber que irá entrar em águas rasas e isso deve estar anotado na carta náutica; talvez seja necessário reduzir a velocidade para inibir o squat.

In certain circumstances a ship may be required to navigate
in areas with a reduced under-keel clearance (UKC). It is important
that the reduced UKC has been planned for and clearly shown. In
cases where the UKC is less than 10% of the deepest draught, or
other such percentage as was agreed at the appraisal stage, then it is
essential that the OOW is aware of such reduced UKC. He also
needs to be aware that speed may have to be reduced in order to reduce squat with its consequent reduction in draught. Such information needs to be shown on the chart.

Question 20

Tidal window

Answer 20

In tidal areas adequate UKC may only be attainable during
the period that the tide has achieved a given height. Outside that
period the area must be considered no-go. Such a safe period, called
the Tidal Window, must be clearly shown so that the OOW is in no
doubt as to whether or not it is safe for the ship to proceed.

Question 21

Stream Allowance

Answer 21

Realizar correções de rumo antes que a corrente altere a derrota do navio. Essa medida é necessária em águas confiandas ou próximas à costa, cujos dados estão presentes em cartas (Ocean Passages for the World, Routeing Charts and Pilot Books).

In open sea situations track correction is often made after the
ship has been set off track by the tidal stream and/or current. Such
correction may be adequate in offshore situations, where the ship is
not close to danger, but as the planned track approaches the coast it
is better to make tidal and current correction prior to its taking effecl
Current information, set and rate is often available on the chart
though more detailed information is given in Ocean Passages for the
World, Routeing Charts and Pilot Books (see Appraisal sections 3,4
& 5). Currents vary according to their location and the season and
may be influenced by changes in meteorological conditions.
Tidal information is available from Charts, Tide Tables and
Tidal Atlases, further local information being available in Pilot Books
(see Appraisal sections 5, 7 & 8.) Tidal streams vary according to
the time of high water and the phase of the moon (neaps and springs)
and can be influenced by local meteorological conditions.
When the actual time of transit of a given area is known the
Tidal Heights and Streams can be calculated and due allowance
made for these streams in order to calculate the course to steer to
achieve a planned track. As well as adjusting these allowances, as
the tidal stream varies according to location and time, the OOW
must still carefully monitor the ship’s position and adjust the course
steered to maintain the planned track.

Question 22

Course Alterations and Wheel Over

Answer 22

Em águas restritas ou rasas, muitas vezes, é necessário alterar o curso antes do esperado; o que não ocorre em passagens oceânicas, que utilizam cartas náuticas de pequena escala.

Quando essas mudanças ocorrem, é necessário anotá-las na carta náutica e utilizar de marcações visuais e de radar para utilizar o Prallel Index.

In the open sea and offshore coastal waters when navigating on small scale large area charts, course alterations will usually coincide with the planned track intersections. This will not be the case in confined waters when navigating with large scale charts and where the margins of safety may be so close as to require the ship to commence altering course at the wheel over position, some distance before the track intersection in order to achieve the new planned track.

Usually the pilot using his judgement, based upon his experience, will determine such wheel over. However, ship’s officers, not having such experience should determine such wheel over positions from the ship’s manoeuvring data and mark them on the chart. Suitable visual and radar cues should then be chosen to determine when the ship is at the wheel over position. The best cues for large alterations of course consist of Parallel Indexes or visual bearings parallel to the new track, whereas for small alterations a near beam bearing is often better.

Even when the pilot has the con the wheel over position should
be shown on the chart so that the OOW will be aware of its imminence and importance. It is also part of the ship’s officers’ monitoring of the pilot.

Question 23

Parallel Indexing (PI)

Answer 23

Parallel Indexing (PI) is a useful method of monitoring cross track tendency in both poor and good visibility. It is good practice to inconspicuously mark the planned Plan the chart at the planning stage. Like any radar technique, it is advisable to practice using PIs extensively in good visibility before placing total reliance on them when thick weather makes visual navigation methods impossible.

This simple and effective method of continuously monitoring the ship’s progress is carried out by observing the movement of the echo of a radar conspicuous navigation mark with respect to track lines previously prepared on a reflection plotter or by using ARPA index lines. It is most effective when the radar is in the North up, relative motion mode ship centred.

A fixed radar target, such as a lighthouse or a headland, will
apparently track past the own ship, depicted as being at the centre
of the screen, on a line parallel and opposite to the ship’s ground
track. Any cross track tendency, such as may be caused by a tidal
stream, will become apparent by the target moving off the parallel
line.

The parallel index may also be used to monitor other events,
e.g. a wheel over position. In this case the range and bearing of the
target at the wheel over point and the new track is marked on the
PI. This also allows for a distance cOWltdown to be made and the new track can be subsequently monitored.

Question 24

ARPA Mapping

Answer 24

Many modem ARPAs have the facility to generate synthetic maps that can be stored in a retrieval system. In some instances, such maps may be stabilised through an electronic navigational system, but such facilities should be used in addition to and not to the exclusion of other systems.

Question 25

Waypoints

Answer 25

A waypoint is a position shown on the chart where a planned change of status will occur. It will often be a change of course but may also be an event such as:

I End or beginning of sea passage.
2 Change of speed.
3 Pilot embarkation point.
4 Anchor stations, etc.

Waypoints may also be used as useful reference points to detennine the ship’s passage time and whether or not a schedule is being maintained. Such information can be included in the notebook relevant to the plan or checked when it has been included in the appropriate electronic navigational system. Where an electronic navaid which stores waypoint information is in use, care should be taken to ensure that waypoint designators remain unifonn throughout the plan.

Question 26

Aborts and contigencies

Answer 26

No matter how well planned and conducted a passage may be, there may come the time when, due to a change in circwnstances, the planned passage will have to be abandoned.

Question 27

Point of no return

Answer 27

Ao se aproximar de águas restritas, há um ponto em que não é mais possível retornar, é necessário continuar. Isso se pode dar por falta de espaço para manobrar ou por impossibilidade de retornar à derrota por maré ou profundidade.

O planejamento da derrota deve levar consideração o ponto de não retorno, devendo ser desenhado na carta; este local, todavia, pode variar de acordo com a velocidade, o arco de manobrabildiade da embarcação, a corrente e situações climáticas.

Deve haver um planejamento para chegar à águas seguras.

Question 28

Razões de abortar (abort)

Answer 28

1 Deviation from approach line.
2 Machinery failure or malfunction.
3 Instrument failure or malfunction.
4 Non availability of tugs or berth.
5 Dangerous situations ashore or in the harbour.
6 Sudden changes in weather conditions such as onset of poor visibility or dangerous increase in wind speed or direction.
7 Any situation where it is deemed unsafe to proceed.

Question 29

Contigencies

Answer 29

Having passed the abort position and point of no return the bridge leam still needs to be aware that events may not proceed as planned and that the ship may have to take emergency action. Contingency plans need to have been made at the planning stage and clearly shown on the chart so that the OOW does not have to spend time looking for and planning safe action, but has instantly available action to correct the situation.

1 Alternative routes.
2 Safe anchorages.
3 Waiting areas.
4 Emergency berths.

Situações em que o calado não é suficiente ou de corrente forte, logo que apenas pode ser navegada em determinados períodos do dia, devem ser anotadas na carta náutica.

Having drawn no go areas, the margins of safety and the track to be followed, the planning should now be concentrated on ensuring that the ship follows the planned track and that nothing can occur which is unexpected or cannot be corrected.

Question 30

Position Fixing

Answer 30

A variety of position fixing methods is now available but it must not be assumed that anyone of these methods will suit an circumstances.

Question 31

Primary and Secondary Position Fixing

Answer 31

A fim de fixar a posição da embarcação, será necessário utilizar algum método que forneça a posição da embarcação. Em um primeiro momento, pode ser o GPS, posteriormente o Loran C, depois o radar com marcas visuais.
O importante é determinar qual será o método principal e complementar para cada momento da passagem.

Question 32

Radar Conspicuos Objects and Visuals Navaids

Answer 32

In order to reduce the workload while navigating in coastal waters, the navigator will have determined and planned the primary and secondary methods of fixing. To further reduce the OOW’s workload the navigator will have studied his chart at the planning stage and decided which radar conspicuous marks and visual aids are to be used at each stage of the passage. Such unifonnity will not be confusing to the watch relief, nor to the master should he have reason to come to the bridge.

Question 33

Landfall Lights

Answer 33

Estudar as luzes no momento do planejamento.

When making a landfall it should not be necessary for the OOW to have to minutely examine the chart to find which lights will be seen first. These will have been clearly shown on the chart with their maximum visibility range so that the OOW can concentrate on actually looking for the light concerned, not looking on the chart trying to discover which lights should visible. By determining the bearing and rangp. of a. “dipping light” the OOW can obtain an approximate position, often long before radar can
have detected such light.

The same applies when passing along a coastline or through constrained waters. As lights shown on a chart look similar they need to be studied to determine their individual significance. This needs to be done at the planning stage, not the operational stage when the OOW concerned may be too busy to spend time behind the chart table. See section on range of lights below.

Question 34

Radar Targets

Answer 34

Similarly with radar targets. A little time spent at the planning stage will soon detennine which targets are to he looked for and used; a steep-to islet is going to he more reliable than a rock awash. Highlight on the chart Racons and other radar conspicuous objects that will be used for position fixing. Highlight visual navaids as appropriate, differentiating between floating and fixed navaids and high powered and low powered lights, bearing in mind that, of choice, floating navaids should not be used as they may not be in their charted position.

Question 35

Buoyage

Answer 35

Whenever buoys or other floating navrnarks are being used as position fIxing aids their own pOSition must be first checked and confirmed that they are as shown on the chart. In situations where buoy fixing is critical, such positions can be predetermined at the planning stage by noting their range and bearing from a known fixed object or by confinning from the local YTS that all navigational aids are as charted.

Question 36

Fix Frequency

Answer 36

Irrespective of the method of fixing to be used, it is necessary to establish the required frequency of the fixing. Quite obviously, this is going to depend on the circumstances prevailing, a ship close to danger will need to be fixed more frequently than one in the open sea. As a guideline, it is suggested that fixing should be at a time period such that it is not possible for a ship to get into danger between fixes. If it is not possible to fix the position on the chart at such frequency (fixes at intervals of less than three minutes can be very demanding) then alternative primary navigation methods. Parallel Indexing, for example, should be considered.

Question 37

Fix Regularity

Answer 37

Having established the fix frequency it is good practice to ensure that fixes are in fact made at that frequency, not as and when the OOW thinks fit. The only exception to this will be if the OOW has other priorities to contend with, e.g. course alterations for traffic or approaching a critical wheel over position. In this laUer case the ship’s position should be established immediately before the turn and then again, as soon as possible, on completion.

Question 38

Additional Information

Answer 38

Although not essential to the safety of the ship, a lot of additional information can be shown on the plan which, by reminding the OOW of his obligations or reminding him to make certain preparations, will make the execution of the voyage simpler.

Such infonnation will include the items listed below:

Reporting Points - necessário reportar às autoridades algumas informações;
Anchor Clearance;
Pilot Boarding Area;
Tug Engagement;
Traffic Areas

Question 39

Transits (Ranges)

Answer 39

TranSits, (known as Ranges in America) i.e., the line on the chart upon which an observer would see two identifiable objects in line, can be used to give the OOW a quick indication of his position. Although it is only a single position line its advantage is that it requires no use of instruments but can be seen by eye. For extreme accuracy the distance between the observer and the nearer object should be no more than three times the distance between the objects observed, though transits of greater than this distance can be used to advantage.

Transits are sometimes printed on charts of inshore waters but good use can be made of natural and clearly identifiable transits found at the planning stage and drawn on the chart.

Transits can also be used as a cue for a pre-arranged action to
be taken, e.g. wheel over, or as a reminder that an event is about to
occur.

Question 40

Compass Error

Answer 40

Transits may used to determine gyro and magnetic compass errors by comparing charted and observed bearings.

Question 41

Leading Lines

Answer 41

Leading lines are often shown on charts. In this case the transit printed on the chart is a track line to be followed to ensure that the ship passes clear of danger. By observing that the leads are in line the OOW is assured that his ship is on the planned track.

Question 42

Clearing Marks

Answer 42

Clearing marks can be used to ensure that a ship is remaining within a safe area or is not approaching a danger. In Figure 8 the clearing bearing is shown so that as long as the Western end of Rat Island remains open of and to the left of Sheep Buoy then the ship is making a safe approach with reference to that side of the channel.

Question 43

Head Mark

Answer 43

Often a ship is required to follow a track in narrow waters without the benefit of a leading line. In this case a suitable head mark should be selected. This should be a readily identifiable conspicuous object shown on the chart, which lies on the projection of the required track at that part of the passage. As long as the compass bearing of the head marker, corrected for errors and preferably taken with a centre line repeater, remains constant, (i.e, the same as the required track) the ship is remaining on track. It should be noted that the ship need not necessarily be heading directly at the object, only that it is on the line of the required track. In many cases the ship’s head will need to be offset to allow for tide or leeway.

Such head mark can only be monitored by a compass bearing; a relative bearing can become completely misleading as a vessel can actually circle a target on the same relative bearing.

Question 44

Clearing Bearings

Answer 44

In the event that no clearing marks are available a single identifiable charted object may be Similarly used. In Figure 9 as long as the bearing of the mark remains within the range 028T-042T then the ship will be in safe water. These clearing bearings should be shown on the chart and may be shown as NLT 028”T and NMT 042”T (not less than/ not more than).

Observing clearing bearings and clearing marks cannot be considered to be “fixing” the ship but can assist the OOW to ensure that his ship is not standing into danger. Similarly using dipping distances, whilst not being considered to be an accurate fIx, can make the OOW aware that he is approaching danger.

Question 45

Range of Lights

Answer 45

The maximun range at which a navigational light can be seen
depends upon three separate factors:

1 The combined height of eye of the observer and the elevation
of the light
2 The intensity of the light.
3 The clarity of the atmosphere.

Question 46

Geographical Range

Answer 46

The greater the height of the light the greater the distance at which it will be visible; equally the greater the height of eye of the observer, the further he will see the light. These two factors combined will give a maximum range of visibility called the Geographical Range and may be obtained from tables in the Ust of Ughts. In practice, this range will be severely reduced if the light observed is only low powered and therefore not capable of being seen at its Geographical Range.

Question 47

Luminous Range

Answer 47

This is the maximum distance at which the light can be seen and is dependent upon the intensity of the light and the atmospheric visibility prevailing. It takes no account of the height of the light nor that of the observers eye. Obviously, the more intense the light, the further it will be seen, whatever the state of the atmosphere, and the appropriate table will give a good indication of how far the light can be expected to be seen.

Question 48

Nominal Range

Answer 48

The range shown on the chart, beside the light star, is usually the Nominal Range, i.e. the luminous range when meteorological visibility is to miles. This is not invariable though. Some countries, such as Japan, chart the Geographical Range; some such as Brazil, the Geographical or Nominal according to whichever is the greater. It is the navigator’s responsibility to make himself aware of which range is shown and to ensure that the OOWs are also aware of this fact.

Question 49

Landfall Lights

Answer 49

At the planning stage of the voyage, the navigator will have the opportunity to determine the maximum distance at which a landfall light should become visible. A comparison of the nominal and geographic ranges can be made and the lesser of the two selected as being the range at which the light should be seen, assuming meteorological visibility of at least 10 miles. It should be noted that only lights whose luminous range exceeds their geographical range could be considered as giving an approximate fix. In any case the arcs of maximum visibility should be drawn on the landfall chart so that the OOW is aware of the likelihood of seeing lights and which
ones he should see first.

Question 50

Extreme Range

Answer 50

When approaching the coast lights will come into view according to their height, their intensity and the ambient visibility.

Sometimes the first indications of the proximity of the coast will be powerful navigation lights that may be seen before the radar can detect them as targets. Whilst not pretending that sighting the lights can be an accurate fix, an observation of the compass bearing at the time of sighting and plotting this with the extreme range of the light at this time will give the OOW an awareness of the proximity of danger.

In the event that a light is not sighted as expected then the OOW will be aware that the ship is:

1 Not where he anticipated it to be.
2 The light is unlit or obscured in cloud.
3 There is poor visibility between the ship and the light.

The actual cause must be determined by his own judgement. The fact is that there is something which is not quite as it should be.

Question 51

Echo Sounder

Answer 51

Some ships leave an echo sounder running at an Limes. On ships where this is not the case, it is good practice to switch the echo sounder on prior to a landfall being made. As in the case ofa light at maximum range, whilst not providing a fix, the actual decrease in soundings will make the OOW more aware that he is approaching danger

Question 52

Chart Overcrowding

Answer 52

The infonnation required to monitor the passage will, in many instances, be shown on the working charts. In some situations this may not he possible; there may be too much information needing to be shown, thus overcrowding the working area, or even blotting out certain chart details.

In some cases this overcrowding can be reduced by writing the required information wen clear of the track, e.g. on the land, and drawing attention to it by either a connecting
line or a reference letter.

Question 53

Planning Book

Answer 53

In any case, certain information may be better written in a planning book, e.g. times of high and low water, times of sunrise and sunset, VHF working frequencies, etc. Where a ship uses a port regularly the navigator may prefer to put the whole of his plan into a planning book in addition to the chart, so that it can be referred to at a later date. He may choose to hold such information on a computer, where it can be accessed and modified when making a return visit.

Question 54

Conning Notebook

Answer 54

Depending upon the length and complexity of the passage, or certain parts of it, it is good practice for an abbreviated edition of the plan to be made into a notebook. The person having the con can then update himself as and when required without having to leave the conning position to look at the chart.

Question 55

Masters Approval

Answer 55

On completion the plan must be submitted to the master for his approval. Opportunity must also be taken to make all members of the bridge team aware that the voyage/ passage plan is complete and to invite them to both examine it and make such comment as is necessary.

Question 56

Plan Changes

Answer 56

All members of the bridge team will be aware that even the most thorough plan may be subject to change during the passage. It is the responsibility of the person making such changes to ensure that such changes are made with the agreement of the master and that all other members of the team are also advised.

Question 57

Automatic Identification System (AIS)

Answer 57

The requirement to carry AIS means that additional information may be available which othetwise could not be obtained. Of particular value is the identification of ships hidden by land or in rain. Also, early detection of target heading changes can be observed. Because of manual inputs into the system, care must be taken when using the information for decisions.