Courses and Explanation of the Reference Point Page 1 of 21

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Trevor Paul
5 years ago
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1 Courses The course tables below cater for a variety of course configuration of varying sizes. These tables can be used when there is one or a number of mark laying boats. For novice mark layers the race officer may choose to just give the mark layer the reference point latitude and longitude (numerically or by pinging ) and then the range and bearing of each mark in turn to enable the mark layer to go to the position of this mark. For experienced mark layers, all race officer needs to tell the mark layer is the reference point latitude and longitude, the course axis and length of the first beat. In this case mark layers need to familiarise themselves with the tables and what they contain prior to going afloat. 45, 90, 45 Triangle 60, 120, 120, 60 Trapezoid, Reach half inner beat length - Start Finish together 70, 120, 120, 70 Trapezoid, Reach half inner beat length - Start Finish together 60, 120, 120, 60 Trapezoid, Reach half beat length Equal beats, separate finish 70, 120, 120, 70 Trapezoid, Reach half beat length Equal beats, separate finish 60, 120, 120, 60 Trapezoid, Reach two thirds beat length Equal beats, separate finish 70, 120, 120, 70 Trapezoid, Reach two thirds beat length Equal beats, separate finish Windward/Leeward with offset. 70, 120, 120, 70 Trapezoid, Reach two thirds beat length Equal beats, with beat to finish (Laser/Laser Radial) As the beat length increases, the shape of the course remains the same with other legs increasing in the same proportion, apart from the distance from the start to the mark 4 gate and from mark 3 to the finish. The tables should be used with common sense. The size of the course will depend on wind speed, the type of boats and the number of laps to be sailed. Course laying is an art and a science. Once a mark boat is in the position given using the tables, checks should be made and adjustments carried out to ensure marks are laid to achieve the objective of fair courses laid so each windward beat and run is as true to the actual wind direction as possible and the angle for reaches is consistent with that required by the classes concerned. The Reference Point. When using a GPS and these tables to assist with mark laying each mark is defined by the range and bearing from a single point. This allows the initial position of each mark to be found independently of any other. The final position of the mark should be adjusted to account to the actual wind conditions in that part of the course. For want of a better name this single point is call the Reference Point. There is nothing unique or special about this point, however, some points are more convenient than others. Once the beat length is close to 1 nautical mile or more any of the first three reference points described below will allow a good course to be laid using the tables. The tables have been calculated using the middle of the mark 4 gate. Total course distances have been calculated using this reference point. One advantage of mark layers familiar with entering the reference point by latitude and longitude, is there is no need for some mark layers to ever need to be in the starting area therefore minimising the time required. It may decrease the amount of fuel used and allows mark layers time to do other task like measuring the wind. Also when there is more than one mark layer competence in sharing coordinates of the positions of marks allows a course to be swung from any mark for course changes. (1) Middle of the mark 4 Gate (or Mark 3 of a Triangular course) Pros (a) Mark 1 directly upwind of middle of the starting line and mark 4 for accurate inner loop beats (b) Lengths of other legs are proportional to the distance from the reference point to mark 1. Courses and Explanation of the Reference Point Page 1 of 21

2 Cons (c) The reference point is the turning point for the inner loop for course changes. (d) The tables are set up using this point. (a) Depends of the relationship between the starting line length and the distance above the starting line of Mark 4 gate. (b) Requires use of the Project Location or similar function to determine the latitude and longitude (c) Is an imaginary point nothing gets laid there. Its position need to be given to other mark boats by a latitude and longitude. (2) Middle of the starting line Pros (a) Mark 1 directly up wind of the middle of the starting line for accurate first beat. (b) Only dependent of the starting line length. Cons (a) Inner and outer loops different lengths. (b) Requires the use of the Project Location or similar function to determine the latitude and longitude. (c) Is an imaginary point nothing gets laid there. Its position need to be given to other mark boats by a latitude and longitude. (3) The location of the signal boat Pros (a) Easy to calculate as it the signal boats location thus the signal boat GPS has this information at all times without calculation. (b) An actual identified point which can be pinged by a mark boat thus preventing the need to transmit the information. (c) A point which can be seen from other parts of the course as the signal boat is at this position. (d) If the gate is placed directly upwind of the signal boat, the signal boat can signal a change of course. Cons (a) For long starting lines and short courses the pin end of the starting line is skewed. Example: First beat 0.35 nm (650 m) Starting line length 0.1 nm (185 m) If the signal boat is directly downwind of mark 1 the pin end is skewed by nm (555) m 0.05 nm (92 m) 0.1 nm (185 m) Courses and Explanation of the Reference Point Page 2 of 21

3 (b) Inner and outer loops will be of different lengths. Courses and Explanation of the Reference Point Page 3 of 21

4 45, 90, 45 Triangular Course Start/Finish 0.05 nt mi downwind of mark 3 or Finish 0.05 nt mi upwind of Mark 1 or two thirds the beat length downwind of Mark 2 Course Axis Angles in degrees Course Axis Angles in degrees Start to Start Pin 3 Finish Start to Start Pin 3 Finish 3 (3S/3P) to 1 to to to to to to to to to 3 (3S/3P) to 1 to to to to to to to to to Pin Start Finish 3 3 to Pin Start Finish Courses and Explanation of the Reference Point Page 4 of 21

5 45, 90, 45 Triangular Course Start/Finish 0.05 nt mi downwind of mark 3 or Finish 0.05 nt mi upwind of Mark 1 or two thirds the beat length downwind of Mark 2 Leg lengths Course Distances 3 to 1 3 to 2 1 to 2 U1 U2 U3 T1 T2 T3 1 to 3 2 to 3 2 to U1 Start Finish (Upwind) U2 Start S/3P Finish (Upwind) U3 Start S/3P Finish (Upwind) T1 Start Finish (Downwind) T2 Start S/3P 1 Finish (Downwind) T3 Start S/3P Finish (Downwind) Courses and Explanation of the Reference Point Page 5 of 21 2 Wind Reference Point for Laying the course 45 Finish Start nt ni 0.05 nt mi

6 Trapezoid 60, 120, 120, 60 interior angles Start Finish together. Reach = half beat length Course Axis Angles in Degrees Course Axis Angles in Degrees Start Start Line Line Courses and Explanation of the Reference Point Page 6 of 21

7 Trapezoid 60, 120, 120, 60 interior angles Start Finish together. Reach = half beat length Lengths in Nautical Miles Total Course Length in Nautical Miles I1 I2 I3 O1 O2 O Wind 4S 1 4P Start Finish I1 Start 1 4S/4P Finish I2 Start 1 4S/4P 1 4S/4P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P Finish O1 Start Finish O2 Start Finish O3 Start Finish Courses and Explanation of the Reference Point Page 7 of 21

8 Trapezoid 70, 110, 110, 70 interior angles Start finish together. Reach = half beat length Course Axis Angle in degrees Course Axis Angle in degrees Start Start Line Line Courses and Explanation of the Reference Point Page 8 of 21

9 Trapezoid 70, 110, 110, 70 interior angles Start finish together. Reach = half beat length Lengths in Nautical Miles Total Course Length in Nautical Miles I1 I2 I3 O1 O2 O Wind 4S 1 4P Start Finish I1 Start 1 4S/4P Finish I2 Start 1 4S/4P 1 4S/4P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P Finish O1 Start Finish O2 Start Finish O3 Start Finish Courses and Explanation of the Reference Point Page 9 of 21

10 Trapezoid 60, 120, 120, 60 interior angles equal beats. Reach = half beat length Course Axis Angles in degrees Course Axis Angles in degrees F F Start F F Start Line Line Courses and Explanation of the Reference Point Page 10 of 21

11 Trapezoid 60, 120, 120, 60 interior angles equal beats. Reach = half beat length Lengths in Nautical Miles Total Course Length in Nautical Miles I1 I2 I3 O1 O2 O I1 Start 1 4S/4P Finish I2 Start 1 4S/4P 1 4S/4P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P Finish O1 Start Finish O2 Start Finish O3 Start Finish nm Wind Finish 4S Start 1 4P Lay the finish using the position of Mark 3 as a guide. Courses and Explanation of the Reference Point Page 11 of 21

12 Trapezoid 70, 110, 110, 70 interior angles equal beats. Reach = half beat length Course Axis Angles in degrees Course Axis Angles in degrees F-3 3-F Start F-3 3-F Start Line Line Courses and Explanation of the Reference Point Page 12 of 21

13 Trapezoid 70, 110, 110, 70 interior angles equal beats. Reach = half beat length Lengths in Nautical Miles Total Course Length in Nautical Miles I1 I2 I3 O1 O2 O I1 Start 1 4S/4P Finish I2 Start 1 4S/4P 1 4S/4P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P Finish O1 Start Finish O2 Start Finish O3 Start Finish nm Finish Wind 4S Start Lay the finish using the position of Mark 3 as a guide. 1 4P Courses and Explanation of the Reference Point Page 13 of 21

14 Trapezoid Course 60, 120 interior angles equal beats. Reach = 2/3 beat length Course Axis Angles in Degrees Course Axis Angles in Degrees Signal Pin Finish Signal Pin Finish Pin Signal Finish Pin Signal Finish Courses and Explanation of the Reference Point Page 14 of 21

15 Trapezoid Course 60, 120 interior angles equal beats. Reach = 2/3 beat length Leg lengths Course Distances 4-1 & & 2-1 I1 I2 I3 2-3 & 3-2 & & 3-4 O1 O2 O I1 Start 1 4S/4P 1 2 3P Finish I2 Start 1 4S/4P 1 4S/4P 1 2 3P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P 1 2 3P Finish O1 Start 1 2 3S/3P 2 3P Finish O2 Start 1 2 3S/3P 2 3S/3P 2 3P Finish O3 Start 1 2 3S/3P 2 3S/3P 2 3S/3P 2 3P Finish 3S 2 3P Finish Wind Reference Point for Laying the course S 1 Start 4P Courses and Explanation of the Reference Point Page 15 of 21

16 Trapezoid Course 70, 110 interior angles. Reach = 2/3 beat length Course Axis Angles in Degrees Course Axis Angles in Degrees Signal Pin Finish Signal Pin Finish Pin Signal Finish Pin Signal Finish Courses and Explanation of the Reference Point Page 16 of 21

17 Trapezoid Course 70, 110 interior angles. Reach = 2/3 beat length Leg lengths Course Distances 4-1 & & 2-1 I1 I2 I3 2-3 & & & 3-4 O1 O2 O S 2 3P Wind Reference Point for Laying the course S 1 Start 4P I1 Start 1 4S/4P 1 2 3P Finish I2 Start 1 4S/4P 1 4S/4P 1 2 3P Finish I3 Start 1 4S/4P 1 4S/4P 1 4S/4P 1 2 3P Finish O1 Start 1 2 3S/3P 2 3P Finish O2 Start 1 2 3S/3P 2 3S/3P 2 3P Finish O3 Start 1 2 3S/3P 2 3S/3P 2 3S/3P 2 3P Finish Finish Courses and Explanation of the Reference Point Page 17 of 21

18 Windward-leeward courses with 80 offset mark 1A Course Axis Course Axis 4 1A 1A A 1A - 1 Signal Pin - 4 1A 1A A 1A - 1 Signal Pin - - Pin Signal - Pin Signal Courses and Explanation of the Reference Point Page 18 of 21

19 Windward-leeward courses with 80 offset mark 1A Leg lengths Course Distances A 1-4 1A - 1 W1 W2 W3 W W1 Start 1 Finish W2 Start 1 4S/4P 1 Finish W3 Start 1 4S/4P 1 4S/4P 1 Finish W4 Start 1 4S/4P 1 4S/4P 1 4S/4P 1 Finish Reference Point for Laying the course 4S Wind 1A Start 80 4P 0.02 nt mi (40 m) 1 Courses and Explanation of the Reference Point Page 19 of 21

20 Laser and Laser Radial Trapezoid Course 70, 110 interior angles Course Course Axis Trapezoid Course 70, 110 interior angles Axis Signal Pin Signal Pin Pin Signal Pin Signal 5 - F F F F Courses and Explanation of the Reference Point Page 20 of 21

21 Laser and Laser Radial70 Trapezoid Course Lengths to Marks and Course Lengths Equal beats, Reaches (1-2 and 3-5) two thirds of beat length Start 0.05 nt mi downwind of 4S/4P(4) 4-1 & & F I1 4-2 & & & F - 5 O S 2 3P Wind S 1 Start Finish Reference Point for Laying the course 4P I1 Start 1 4S/4P 1 2 3S/3P 5 Finish O1 Start 1 2 3S/3P 2 3S/3P 5 Finish 5 Courses and Explanation of the Reference Point Page 21 of 21

J/109 Deep Keel 150% Genoa, 121sq.m. A-Sail VPP Data: Page 1 of 5 Based on ORC IMS 2004 Velocity Prediction program

J/109 Deep Keel 150% Genoa, 121sq.m. A-Sail VPP Data: Page 1 of 5 Columns are as follows: VTW=Velocity True Wind, BTW=Beta True Wind (angle), VAW=Velocity Apparent Wind, BAW=Beta Apparent Wind (angle),