Page 42 - Race

1. On a windward-leeward course using 2 marks the best
compromise is to set the course on the Sailing Wind. In
this situation the course will be equally skewed upwind
and downwind with boats spending 60 seconds on the
long tack/gybe and 26 seconds (43%) on the short
tack/gybe.

2. By using a third mark on a windward/leeward course (ie
including an offset mark) an increase in the distance
between the windward mark and the offset mark will
result in a perfect beat and a perfect run. The leg
between the windward mark and the offset mark in this
situation may be referred to as a 'tidal correction leg'.
The limitation of this manoeuvre is that it will only work if
the tide is flowing from left to right across the course. When in the opposite direction starboard
roundings at the marks are required. This is unpopular with some classes who would prefer
option 1 above.

3. When more marks are available the X course can be used:

4. When the course is set over a very large area as is
often the case in keelboat racing, a further technique
can be used, often referred to as a 'Tidal Cascade'.
Note that all the upwind legs are parallel to each
other as are the downwind legs. The downwind legs
have the appropriate tidal offset as do the upwind
legs. When using laid marks rather than fixed or
permanent special marks, this course requires an
extremely skilful mark laying team. One advantage is
that each mark can be laid just before the fleet arrive
at the previous mark. This will allow the RO to
calculate the tidal strength and the wind strength
accurately for each leg of the course.

Version March 2018 40