Lay line Revisited

Special Thanks to John Papadopoulos for the drawing and to Travis Wilson for the photo.

Special Thanks to John Papadopoulos for the drawing and to Travis Wilson for the photo.


Lay line Revisited

By Andrew Kerr

October 2006

Very often, back on shore after a day’s racing, some very familiar post race stories are told by competitors – “We ended up barging at the start and got shut out” or “We were doing really well and then over stood the weather mark and let four boats in” – or perhaps “We ended up over standing the leeward mark and gave up three boats on the inside when that shift came in.”  Sound familiar?  It has happened to all of us and it costs places in races and regattas and all of them relate to lay lines.

A team is certainly not going to nail every lay line but they can have a set of principles that can help them increase there chances of making a good call.  Let’s look at some lay line scenarios around the racecourse.

But first lets clarify the term lay line.  A lay line, for this article, is the straight line course you would sail to fetch an object (e.g. a mark of the race course).  Thus lay lines exist at every mark of the course, including those that define the ends of the start and finish lines.

Scenario 1:  The race committee has set up the starting line with the committee’s signal boat on the starboard end of the starting line.  Wanting to start at the starboard end of the start line, so that they can be the first boat to tack onto port, the team gets caught barging into too small of a space between the RC boat and the nearest competitor.  They have to “bail out” and re-approach the start line - ending up very late (and behind).  How do you win this coveted (but dangerous) position on the line?

Action:  The solution is to better identify the time and place to make your final turn upwind to the starting line so that you don’t accidentally leave too much space between you and the RC boat (for someone to barge into) or too little space to operate in, thus becoming a barging boat to the next boat down the line.  Key to making this approach is to identify a “safe” layline to the starboard end of the starting line and to make your final approach slightly below this line.  The “safe” lay line is the close-hauled course that will put you about a boat length or so to leeward of the RC boat - leaving room to head up if a leeward boat luffs you or to defend against a boat trying to barge between you and the RC boat.

To find this lay line, reach below the RC boat, on starboard tack, to the point where you think you can fetch (when sailing close hauled) the RC boat end of the start line.  Go about half a boat length further and then head up to close-hauled.  You are now on the “safe” lay line.  Note the compass heading for future reference.

The next task is to pick your distance, along this lay line, to make your final approach to the start line and to make a mental note of it.  This will be the place to sail to, whether approaching on port or starboard tack.  In a shifting breeze, note that this “turning point” will move significantly.  The following diagram shows how the turning point moves in location due to 15 degree shifts (left and right).  The diagram below presumes that you always want to turn onto your final approach from a common distance from the start line (i.e. enough room to complete a tack, make some tactical steering changes, accelerate, etc.)

Note that as the wind shifts further to the right (presuming the RC doesn’t reset the line), the turning point moves down and to the left and vice versa for a left shift.

If the line is restricted pre-start, go upwind out side the RC boat and watch the compass numbers on starboard tack.  The team needs to be aware that if the wind shifts the lay line shifts and consequently ones initial assumptions have to be reassessed. 

So if you detect a late wind shift (don’t forget to take periodic head-to-wind compass readings), make a note to adjust your turning point to compensate.

Another key part of being able to hit (and stay on) the starboard lay line accurately is to know what’s happing with the currents (a topic unto itself!).  A good move is to bring a current stick (a water bottle with just a bit of air inside will do) and to test the current near a fixed mark - well before the start and see which way it drifts and at what rate.  This will help you assess its effect on the lay lines and also your approach to the starting line.

It is worth noting that one knot of current is equal to approx. 5 knots of sailing wind and for each 1 tenth of a knot of adverse current, you have to compensate in your tacking angles by at least 4 degrees of tacking angle.

Scenario 2:  The team has a tendency to over stand the lay line to the weather mark and lets boats get inside room for the rounding.

Action: When sailing upwind before the start, note your tacking angles by watching the compass carefully.  These angles will be different in every wind and sea condition.  Practice calling lay lines to a practice mark and see how you do.  Try to judge the lay line when much closer to the mark – make it a rule of thumb to judge the lay line no further than 8 to 10 boat lengths away and youwill be a lot more accurate!

It is always good to bear in mind that once you find your self on the lay line, your chances of gaining in a subsequent wind shift are about zero – that is an encouragement to stay off it and play the shifts to keep your options open.

When the wind is oscillating, try to stay on the lifted tack (i.e. on the tack that sails you closest to the mark) as much as possible.  This helps avoid getting punched to a corner and then trying to judge a lay line from a long way out – a sure way to make an already tricky call much harder!

As you approach the lay line – on port or starboard tack – try to assess what phase the wind is in.  If it is a left phase and you are on port tack (port tack is currently lifted) then you will know that you have to go further to be able to make the mark because you will be headed when you tack onto starboard to make the rounding.  If it is a right phase and you are on port, then you know that you can tack well before a conventional lay line and then get lifted up o the mark on starboard.  Again, being closer to the mark when you judge the final tack will vastly increase the chances of making a good call.

Scenario 3: The team has trouble judging when to jibe for the final approach to the leeward mark and either over-stands, forcing the team to sail extra distance to fetch the fetch the mark, or is shy of the mark, forcing the team to sail lower to fetch the mark but slowing down as a result.

Action:  A very similar approach to upwind lay lines will be helpful – when your team is going downwind before the start – do a number of jibes and note the angle of the turns on the compass.  You will be able to get a sense for the jibe angles in the given wind and sea conditions.

Try to stay on the closest (i.e. most headed) jibe to the mark as long as possible.  Start your down wind leg with the knowledge of how the wind was shifted as you approach the weather mark.  If the wind was in left phase (i.e. you are headed while on starboard tack), stay on starboard on the initial portion of the down wind leg so that you maximize being headed downwind.  Some people remember this by sailing downwind on the opposite tack as what was the lifted upwind tack.

When the wind lifts (wind shifts more towards the stern of the boat), we jibe to play the shift and keep the boat sailing at the deepest angle toward the mark – the exception to this is when there is simply more wind on the other jibe.  In essence, this keeps your team away from the corners downwind and thus reduces the chances of trying to make a lay line call from a long way out.

Like going upwind, the trick is to judge the final jibe close to the leeward mark – the closer you can get to the mark the better the call is likely to be.  Current is also going to be a factor (sweeping from left to right or adverse etc.) so using the current stick before the race as well as taking a bearing on the leeward mark with a hand bearing compass to see the effects the current may be having will help the team decide when to jibe.

In summary, measure your environment (wind angles, current, etc.), make your approaches to lay lines closer to the mark to be fetched, and practice, practice, practice.

Best of luck and have fun at your next regatta.