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- Steering and Sailing Rules
- CONDUCT OF VESSELS WITHIN SIGHT OF ONE ANOTHER
- Q Weather Forecasts
NavigationBy David Byatt – AC UK Drawings by Alex Hunt 
'Navigation is the art of making a safe passage in a vessel from one place to another'. Coastal passages may be made in small craft with the aid of chart, compass, watch, lead line, tide tables and some means of estimating the speed of the vessel through the water. More important than elaborate apparatus are accuracy, alertness and a dislike of taking anything for granted. Navigation within the sight of land involves the simplest of calculations and disaster is often brought about by very simple mistakes due to carelessness or fatigue'. One of the arts of Navigation is knowing when to be absolutely precise and when to be approximate. The skill of the navigator depends on his/her ability to make precise and accurate measurements. For example, a fix may be obtained using three compass bearings of known objects, each bearing being read to the nearest whole or even half-degree. From the plotted position it is possible to plot a course to steer to the nearest half degree. In a small boat even the best helmsman cannot steer a course to this accuracy, so the navigator gives a course to steer to the nearest five-degree mark on the compass card. In a Contest Event the Jurors (the Host Nation) must make it clear what level of accuracy they are looking for, given that contestants have to be ranked at the end of the Contest and accuracy is one of the easiest ways of doing this. All chart work which involves plotting will be assessed on neatness, clarity and accuracy. Where practical navigation events are set, contestants may be expected to keep a 'rough navigator's log book'. This 'log book' which will probably be a sheet of paper will show times of bearings, objects used for Fixes, courses steered, times at which the course is altered, times at which soundings are taken, etc. etc.. Chart work should always be done with a sharp, soft (2B) pencil. All lines should be only as firm and as long as is necessary to show the information required on the chart. A soft eraser should be used on the chart to clean off all marks when finished. Charts are expensive items! Where parallel rules are referred to, a protractor or plotter of whatever design may be substituted, provided only that they produce the result described. A Latitude and Longitude Candidates will be expected to determine the Latitude and Longitude of a given position on a chart and to find a position given its Latitude and Longitude. The parallel rule should be aligned with the nearest line of Latitude on the chart a short line drawn on the chart with a pencil in the approximate position. The same method is used to determine the Longitude; this may alternatively be done with a pair of dividers. Remember that distance is measured on the Latitude scale opposite the position worked on the chart, or on a distance scale if provided. B Plotting a simple compass course. The parallel rule is laid on the chart in the correct position and carefully aligned between the two points between which passage is to be made. Stepping the rule, or rolling, depending on design, to the nearest Compass Rose, the rule is aligned with the centre mark and then checked on the two reciprocal readings on the outer circumference of the Rose. (N.B. All courses and bearings are determined on the outer, or True, compass rose, as this does not change with time). Having determined the True course this must have Variation applied to convert it to Magnetic. For the purposes of the Contests, this will be considered the Compass course. ( Mariners should remember that a proper compass course accounts for Deviation as well as Variation!) C Plotting a Dead Reckoned (D.R.) position. The True course steered from the present known position ( as depicted in Fig 3) or the last estimated position allowing for leeway and drift and set of the tide (as depicted in Fig 2) is laid off on the chart with parallel rule and pencil using the dividers to step off the distance run in the next hour at the current speed, the position is marked with a short line perpendicular to the course, or a cross and the time written beside it. This procedure may be used until the next time it is possible to fix the vessels position, i.e. by three bearing fix. A Fix is a known position and the time is always written on the chart beside it. The D.R. Plot should look like the following:- N.B. An arrow on a line should be at the end of the line for a line of bearing used as a position line and in the middle of the line for a course line.
Contestants should be familiar with the Hand Bearing Compass and able to use one. Three objects on land and identifiable on the chart are chosen at as wide an angle to one and other as possible - ideally 120° apart in order to give the best 'cut', i.e. the smallest triangle or 'cocked hat'. The objects should be listed in the log book, their bearings read and recorded as ---°M and the conversion to ---° True shown in the Log Book by adding or subtracting the Magnetic Variation. Each line of bearing is then laid off on the chart and the centre of the triangle produced indicates the position of the vessel which should be portrayed thus:-
D = T x S T = D/S
The formula T = D/S may be used to calculate the time of arrival at a distant position (e.g. a harbour etc.) First measure the distance on the chart, then divide the distance by the speed and the answer is the time in hours to complete the passage. This may be readily converted to a clock time. G Chart Symbols. Knowledge of principal symbols, sufficient to make a safe passage. For example, the first thing to look at on a given chart; Depths in fathoms, feet or metres? When surveyed, i.e. how reliable? Datum (normally Lowest Astronomical Tide) i.e. what are the true depths likely to be?. Difference between yellow, green, blue and white areas on a Metric Chart. Cautions under the title.
Depths, drying heights, contours of depth at 5,10, 20 metres, etc.. Rocks - which are a hazard to navigation. Awash at Low Water; Less than 6' (2m) at Low Water Nature of the bottom - for anchoring. Sand, Rock, Stones, Mud, Weed. Lights - used for navigation; ability to understand the meaning of; Fl.G.2sec 3m 4M'. Occ: Fl; Q.Fl; Iso
- Mast
- Building - Beacon
- Hilltop - Topographical features, e.g. Cliffs, Dunes, - Marshland, Urban area, etc..
Ability to keep a 'Navigator's Log book'. Note the time of all bearings, showing whether they are True or Magnetic; alterations of course steered; estimation of leeway, etc., etc.. K Use of a Line of Transit to determine movement through the water. Choose two objects that are in line and can form a “range” when crossed. For preference, one should be near the observer and the other far away. When the observer crosses the path formed by these two objects, he is on a line of position (LOP) formed by the two objects. If you alter course and run either away or towards the two marks you may use this Line of Transit as a navigational reference. 
L Leading marks The principle of the transit mark may be used as a leading line to guide a mariner through a deep water channel in a narrows or to avoid offshore dangers to navigation. Such Leading marks are shown on the chart and may be natural features or artificial marks. 
M I.A.L.A. Buoyage. Basic knowledge of Lateral and Cardinal systems. N Collision Regulations. Sufficient knowledge of The Rule of the Road as to avoid collision in normal situations. The following is a précis of the main Rules. For the full Rules consult a Nautical Almanac.
N.B. A Gig under oars is a power driven vessel - an oar is a 'machine'. The term 'sailing vessel' means any vessel under sail provided that any propelling machinery, if fitted, is not being used. d - l) see full regulations in an Almanac, etc.. Steering and Sailing Rules:-CONDUCT OF VESSELS IN ANY CONDITION OF VISIBILITY Rule 4. Rules in this section apply in any visibility. Rule 5. Every vessel shall at all times maintain a proper look-out. Rule 6. Every vessel shall at all times proceed at a safe speed. Rule 7. Risk of collision Every vessel shall use all available means to determine if a risk of collision exists. If there is any doubt, such risk shall be deemed to exist. Rule 8. Action to avoid collisions Any action taken to avoid collision shall be positive Any alteration of course and/or speed shall be large enough to be readily apparent to another vessel. If necessary to avoid collision a vessel shall slacken her speed by stopping or reversing her means of propulsion..
A vessel proceeding along a narrow channel shall keep to the starboard side. Sailing vessels and small vessels (under 20m) shall not impede the passage of a vessel that can only safely navigate within a narrow channel or fairway. CONDUCT OF VESSELS WITHIN SIGHT OF ONE ANOTHERRule 12. Sailing vessels: When two vessels are approaching one another, so as to involve risk of collision, one of them shall keep out of the way of the other as follows:- When each has the wind on a different side the vessel which has the wind on the port side shall keep out of the way of the other. When both vessels have the wind on the same side the vessel which is to windward shall keep out of the way of the vessel which is to leeward. For the purposes of this rule the windward side shall be deemed to be the side opposite the side on which the mainsail is carried. Rule 13. Overtaking Any vessel overtaking another shall keep out of the way of the vessel being overtaken. Notes : Although the overtaking vessel always has the obligation to keep clear, the one overtaken also has a duty not to hamper her. Before altering course always look astern to make sure another vessel is not coming up on either quarter. N.B. This applies to a sailing vessel overtaking a power vessel as well as another sailing vessel. A gig under oars is a power vessel for the meaning of this rule. Rule 14. Head-on situation When two power driven vessels are meeting on reciprocal or nearly reciprocal courses so as to involve risk of collision each shall alter course to starboard so that each shall leave the other boat to port. Rule 15. Crossing situation When two power driven vessels are crossing one another so as to involve risk of collision the vessel which has the other on her starboard side shall keep out of the way of the other and avoid crossing ahead of the other vessel. O Determination of speed of the vessel without instruments. Use of bits of wood, etc., dropped by the bow and timed when passing the stern or use of traditional knotted rope, etc.. P Estimation of position by Bearing and estimated 'Distance Off'. The bearing of an object on the land may be obtained with the hand bearing compass and the distance off estimated. This is a useful approximation, the bearing is reasonably accurate and with practice the estimation of distance also becomes reasonably accurate, if opportunities to observe known distances are taken. Q Weather ForecastsKnowledge of how to obtain a weather forecast - details in Nautical Almanac, etc. Knowledge of what sort of forecast and/or other circumstance might make it prudent to consider that it would be wise to remain in harbour. Download 382.84 Kb. Share with your friends:
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