(Extracts courtesy of A.N.T.A. publications, Ranger Hope © 2008 www.splashmaritime.com.au)
Planning a Safe Course
Before any coastal or ocean voyage commences the navigator needs to have the correct charts and publications for the route that is intended to be taken, and the expected conditions to be encountered.
The digital chart coverage will be listed in your software, or if papercharts are required they can be ascertained from the catalogue charts as mentioned in below.
The seafarer should take into account any expected equipment failure, especially of electronic devices, and know their capabilities and limitations.
Example: You are required to sail your vessel to Samaras Reef from Bundaberg Town Wharf. What charts and publications would you order?
Lay a course from the Burnett River to Samaras Rf., notice it passes close to Lady Elliott Isle. Now pick off the charts required. See figure 1.
AUS 243 - AUS 818 - BA 345 - BA 1024 - BA 349
Other sailing direction publications include the Australian Pilot Vol 111, the Australian National Tide Tables, and possibly Admiralty Charts No 5011.
Figure 1: Extract from Charts AUS 5020A
If you are required to sail from Bundaberg to the Whitsunday’s using an inshore route, then follow similar principles to list the charts and publications you should purchase.
charts are purchased make sure they are corrected to the latest Notices to Mariners.
Then you should commence studying the charts with reference to your publications.
Note that you should use the largest scales available commensurate with your route.
Note whether the soundings are metric or fathoms, underline or circle this with a coloured highlighter.
Read the various notes and mark those applicable to your route.
You should now be ready to lay off suitable courses from your departure position to your terminal position.
You will find that more than one course will be required to your destination, and therefore the selection of the route must combine economy with safety - use the shortest distance only if it is safe to do so.
You should lay off your courses with the following in mind when coasting.
1. Pass close enough to the shore to make certain of seeing and identifying all prominent landmarks, such as lighthouses and beacons, and thus be able to obtain frequent fixes.
2. Keep well clear of hazards and dangers. If a danger sounding is useful, it should be drawn in.
Example: If you decide that 5 metres is your minimum sounding - mark on the chart around dangers, along channels etc.
See Figure 2.
Note Symbols for chart dangers are shown in Admiralty Chart number 5011.
Figure 2: Example of Danger Sounding - Marking of 3 Fathom Line
3. Note which part of your tracks will be covered in daylight and which in darkness. With limited navigational aids it may be prudent to open the distance at night, but remain with the range of lights.
4. Allow for the expected meteorological conditions. These can be obtained from weather reports.
5. When shaping courses allow for wind, tide and current.
6. When Coasting never pass a light without checking its period and characteristic.
Do not rely on light buoys alone, they may not be lit.
Do not fix your position by buoys or other floating aids when other objects are visible close to the ship.
Note: Buoys marking shoals may be moved as the shoal extends. The information may take some time to be broadcasted.
Remember currents and tidal streams often follow coastlines and set into bays and bights.
When passing between islands use objects which are all on one land or all on the other whenever possible. The two islands may have been separately surveyed. See Figure 3.
Figure 3: Groups of Islands Separately Surveyed
Dotted Line A and Line B show the positions obtained using incorrectly surveyed Islands.
taking bearings of low points of land, considerable error may be introduced
unless the High Water Mark (Chartered Coastline) is clearly defined.
This error is well emphasised when there is a large tidal range and the beach gradient is small. See Figure 4.
Figure 4 Error In the coastline due to the Tide
8. Make some consideration for expected traffic density, especially recreational users who may have very little seafaring knowledge. With larger vessels give them plenty of room where their required depth of soundings are limited to narrow areas.
9. Where a chart has a Reliability Diagram, consult it for making decisions on your route. See Figure 5.
Figure 5 Reliability Diagram from Admiralty Chart
10. When transferring from one chart to another, because they may be drawn on different scales be very careful. Transfer your position by bearing and distance of a well charted point common to both charts. Then check by verifying the Latitude and Longitude are the same on each chart.
11. At intermediate points of your route, where an alteration of course is required (Waypoints), select them so that arrival is readily apparent. The course alteration may be made when a conspicuous feature comes abeam, or two features come into transit.
12. Always select objects close to the ship in preference to distant objects for fixing the position. When in pilotage areas (narrow waters) allow plenty of room rounding points of land, shoals, buoys etc, cutting corners is dangerous.
When in pilotage areas (narrow waters) allow plenty of room rounding points of land, shoals, buoys etc.
Cutting Corners is DANGEROUS
Note which way the tide is running by observing buoys and light vessels.
When rounding buoys and LT vessels to windward and against the stream, always give a wide berth. If there is clear water on all sides, pass downstream of them, you may underestimate the strength of tidal stream.
Keeping a Ship’s Log
The ship’s log needs to be kept in ink, as it may be required at some later date to be used in court, and thus becomes a legal document.
Any changes should be crossed out with a single stroke, so that the original is still legible, and then initialled.
The log should be signed by the watchkeeper at the termination of his duty, and the daily page by the Master.
During a navigation watch, the main points to be entered are the position of major course changes, weather, unusual occurrences, drills, emergencies, and other requirements (see the section on Legislation in the module Nautical Knowledge).
Entries are required to be made as soon as they occur and the time entered.
If a ‘log’ is streamed then its reading should be recorded at times of course alteration and thus ‘distance’ obtained, also at other times as required ie running fixes etc.
The ‘compass course’ should show the course steered by the helm (auto or manual).
‘VARIATION’ and ‘DEVIATION’ should be taken from the appropriate place.
The ‘true course’ is the corrected compass course (application VARIATION and DEVIATION).
‘WIND’ given generally as direction and as a force from the Beaufort scale . eg S.W.ly.5.
If allowing ‘Leeway’ then the best estimated angle should be entered
eg (-4 degrees) or (+3 degrees).
Course Made Good (CMG). The actual course over the ground between two fixes.
Barometer – as read from the instrument with correction applied.
Air and sea temperature read if suitable equipment is available for observing.
The Latitude and Longitude should be entered at a fixed interval of time – eg 0800, 1200, 1600 etc.
When altering course, the time should be logged and the position, either Latitude and Longitude, or more generally Bearing and Distance from a charted object –
but preferably not a FLOATING BEACON
If running your depth sounder, then the depth should be recorded.