12 hours ago, Trevor said:

The line does not go through the centre of the marks!!

No, but you could have the finish line marks  parallel to the course from the final mark for the tangent! Much more important that the finish line is perpendicular as I described.

4 hours ago, Guzzilazz said:

No, but you could have the finish line marks  parallel to the course from the final mark for the tangent! Much more important that the finish line is perpendicular as I described.

Best of luck with that. For a start off perpendicular at which end? Plus, it’s impractical to try to achieve it. 

28 minutes ago, Downbytheriver said:

Best of luck with that. For a start off perpendicular at which end? Plus, it’s impractical to try to achieve it. 

So, no more difficult than making sure the start line is fair, by being perpendicular to the course to the windward mark.  Nowhere did I say MUST , but the objective should be to ensure that one end is not favoured compared with the other...

In my long experience as RO for many championships, the fleet will soon tell you, verbally and by demonstration,  whether your start line is correct or not.

 

If you have 24 IOM's evenly spread along a 36mtr long line it can be considered correct!!  even though it may not be tangential or perpendicular !!

Could we not just apply the rule, please! 'The starting and finishing lines shall be between the course sides of the starting and finishing marks'.

If the mark is round then the course side is the point furthest on the course side. The start/finish line is between these points on each mark.

The correct angle to the wind  for the start line is the angle at which competitors decide to spread themselves evenly along the line, and there is no perceived advantage at one end leading to bunching. Competitors may have a very different appreciation of the line compared to the race officer.