Charts and publications

Only official nautical charts and publications should be used for passage planning, and they should be fully corrected to the latest available notices to mariners and radio navigation warnings. Any missing charts and publications needed for the intended voyage should be identified from the chart catalogue and obtained before the ship sails.

For coastal and pilotage planning and for plotting each course alteration point (or waypoint) large scale charts should be used. For ocean passage planning and open water legs smaller scale charts should be used.

Unit 10

1. Read and translate the text

Passage Planning – Part 2

Chart Change

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

Track Consideration

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 and keep sufficiently far off a danger to minimize the possibility of grounding in the event of a machinery breakdown or navigational error.

Distance Off Danger

It is not possible to lay down hard and fast rules regarding the distance off a danger that a ship should maintain. It will depend on:

• The draught of the ship relative to the depth of water.

• The weather conditions prevailing; a strong onshore wind or the likely onset of fog or rain will need an increase in distance off.

• The direction and rate of the tidal stream or current.

• The volume of traffic.

• The age and reliability of the survey from which the information shown on the chart has been derived.

• The availability of safe water.

The following guidelines will help in determining just how far to pass off dangers.

Where the coast is steep to and offshore soundings increase quickly the minimum passing distance should be 1 ½ - 2 miles. Where the coast shelves and offshore soundings increase gradually, the track should ensure that adequate under-keel clearances are maintained. As a guideline:

• Vessel’s draught less than 3 meters – pass outside 5-meter contour.

• Vessel’s draught 3-6 meters – pass outside 10-meter contour.

• Vessel’s draught 6-10 meters – pass outside 20-meter contour.

• Vessels with a draught of more than 10 meters must ensure that there is sufficient under-keel clearance, exercising due caution within the 200 meter line.

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.

Deviation from Track

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 alter 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.

Course Alterations and Wheel Over

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, hot 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.

2. Answer the following questions

1. What considerations should be taken while selecting the track?

2. What are the factors to determine distance off danger?

3. What should be done in case of deviation from the track?

4. What should be done in case of course alterations?

3. Give the summary of the following text

Notes on passage planning in coastal or restricted waters

By comparison with open waters, margins of safety in coastal or restricted waters can be critical, as the time available to take corrective action is likely to be limited.

The manoeuvring characteristics of the ship and any limitations or peculiarities that the ship may have, including reliability problems with its propulsion and steering systems, may influence the route selected through coastal waters. In shallow water, particularly if the ship is operated at speed, ship squat can reduce underkeel clearances.

Ships' routeing schemes and reporting systems along the route, as well as vessel traffic services, should be taken into account.

Coastal weather bulletins, including gale warnings and coastal navigational warnings broadcast by coast radio stations and NAVTEX, may require changes to be made to the route plan.

4. Give the summary of the following text

Notes on passage planning in ocean waters

In open waters, the route selected will be either a great circle, composite great circle or rhumb line route.

When planning ocean passages, the following should be consulted:

• small scale ocean planning and routeing charts providing information on ocean currents, winds, ice limits etc.;

• gnomonic projection ocean charts for plotting great circle routes;

• the load line zone chart to ensure that the Load Line (LL) Rules are complied with;

• charts showing any relevant ships' routemg schemes.

Anticipated meteorological conditions may have an impact on the ocean route that is selected. For example:

• favourable ocean currents may offer improved overall passage speeds offsetting any extra distance travelled;

• ice or poor visibility may limit northerly or southerly advance;

• the presence of seasonal tropical storm activity may call for certain waters to be avoided and an

allowance made for searoom.

Details of weather routeing services for ships are contained in lists of radio signals and in Volume D of the World Meteorological Organization (WMO) Publication No. 9. Long-range weather warnings are broadcast on the SafetyNET Service along with NAVAREA navigational warnings as part of the World-Wide Navigational Warning Service (WWNWS).

Landfall targets need to be considered and identified as to their likely radar and visual ranges and, in respect of lights, their rising and dipping ranges and arcs/colours of sectored lights.

5. Project activities. Make passage planning for any imaginary passage using Passage Planning Manual, available charts and publications.