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Data Reference

Information useful to race officials includes speed charts, 'sailing wind' angles and offset requirements for marks when working in tide, course setting charts, etc.

Speed Charts

Available for download to the right are charts for Olympic classes, Youth classes, IRC keel boats and Cowes Week White Group keel boats.

The Sheet to generate a chart based upon the PN of a boat with a similar speed has been updated to a new version PY Adjusted Trial V3.  The main changes are to remove errors on the 'Enterprise TS' Sheet based upon user feedback.  Further details are included in the header sheet.  This spreadsheet is referred to in both the Race Management Guide and the Guidance Note on using Speed Charts.

Olympic classes and Youth classes charts are in Excel spread sheet format.  The latest Speed Charts are given alongside.  You are advised to check these before a major event in case there have been any changes. 

The Youth Charts have seen significant changes with the addition of a number of other classes that are either pathway, supported or recognised in the RYA Youth programme.  For example the Charts now include the Feva, Mirror and Spitfire double-handed classes, together with the Laser 4.7, Optimist, Topper and Topper 4.2 Classes.  Some changes to the 420 speeds have also been made.

A further change to the Youth classes is the introduction of a Trapezoid course with a committee boat finish (designated as an "IX/OX" course in the Speed Charts).  For this form of course layout data is given for either a different length of second beat or an additional offset for the leeward gate (class dependant).  Refer to the Speed Charts for more detailed information on these courses and any assumptions made.

 In addition, as many of these Youth fleets sail on Inland waters in the UK, a Leg Length column in metres (converted from the value in nautical miles) has been added to aid Race Officers when running events on such waters.

 Further updates will be posted as more information is obtained or feedback is received from any users.

Bob Milner developed 'Speed Carpets' for IRC rated boats and keel boats that race within White Group at Cowes Week (these include XODs, SB3s, Dragons, Darings, Flying Fifteens, Squibs, Redwings, Mermaids and Sonars). The original charts have been replicated using a Spreadsheet and pdf's produced for each graph.  There is also a Time vs Distance chart to determine likely course size for the typical range of VMG's seen by these cruiser/racers.  

Working in Tide

It is well known that the wind a boat sails in is influenced by tide and the resultant 'Sailing Wind' can be calculated accurately.  However, the amount of tide across a leg of a course may vary considerably so the judgement of the race officer is vital.  Sailing Wind produced by tide of 1 or 2 knots at right angles to the Ground Wind (or Gradient Wind) may be downloaded on the right side of this page.

Just as the Sailing Wind is influenced by tide, so is the course and speed a boat travels overgound.  In order to accommodate this both the windward and leeward marks need to be offset downtide.  The amount of offset varies according to windspeed and cross tide.  Charts showing the offset in uniform tidal conditions when it runs at right angles to the gradient wind, can be downloaded from the link on the right side of this page.

Course Setting

This is relatively straight forward for windward/leeward courses and sausage triangles.  When working in tide in a situation where the race officer has only marks enough for one windward mark and a gate at the leeward end, it is impossible to provide a perfect beat and a perfect run on the same course without moving the marks.  An acceptable compromise is to set the course on the 'Sailing Wind'.  The Sailing Wind can be seen, for varying conditions of wind speed and cross tide of 1 and 2 knot, on the right side of this page.

Trapezoid courses offer a greater challenge.  The reference system of laying a trapezoid course was developed at the Olympics in China in 2008.  Having defined the reference point, which is in the middle of the gate at mark 4, mark layers use the tables for the type of course being set (60 or 70 degree trapezoids) and lay each mark in the position shown in the table.  Classical methods should then be used to confirm that the position is correct.  Tables for this system can be downloaded from the link on the right side of this page.

Working in tide and course setting are aspects of race management covered in the Race Management Courses.  Click here to see availability of both RYA and National Courses.

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