You're right of course. Of all the skills we have to learn, this is perhaps the hardest to grasp and so, is too often ignored - except in the excuse-making department, that is!   

So how do we make up our minds which way to go, and what the wind is about to do?

Unfortunately, even daily forecasts are not detailed enough to be of much use on the race course, except that they provide valuable background information. This can be added to what we see happening on the course to enable us to make a best guess of what to do.

In fact, we sailors need to know not only what the wind will be doing during the race, but more importantly, what is going to happen to it on the leg we are on.

This is never going to be a precise science and so we mustn't become too complicated or too obsessed in our analysis. Our forecast is really only one part of our overall race strategy as boat organisation, crew technique, and boat to boat tactics, all play their part, too. Which of them has priority at any one time, depends upon our immediate needs at that moment.

Notwithstanding all that, getting to the first mark in a good position is often everything, and usually decides our finishing position in that race. We therefore need to spend time thinking about our options, and what is likely to be the best way up the beat. Later on during the race of course, we don't have the luxury of that spare time as so many other pressures are heaped on us.

Now, although we can feel the wind, we obviously cannot see it. Therefore we have to observe how it affects things around us – clouds, smoke, trees, other boats, etc.

Our timetable before (and after) the start, should therefore be:

1. On the journey to the Sailing Club
a) What is the wind forecast? Are the clouds moving in the same direction as that forecast?
b) Could any nearby land mass affect that wind at the surface? (e.g. Is the wind along the shore, or is it offshore or onshore?)
c) Are conditions right for a sea breeze to develop (land heating up - gentle offshore breeze)?
d) Is the air stream stable (smooth cloud cover and hazy conditions) or is it unstable (cumulous clouds; clouds with jagged bases and good visibility)?
e) Could it rain during the race?
f) What will the currents be doing?

2. Sailing to the start
a) Note wind direction and speed on a regular basis to see if there are changes. 
b) Is cloud building onshore and disappearing offshore (sea breeze indicators)?
c) Is the cloud base lowering as we look to windward (front approaching)?
d) Is the current affecting the water (wave heights and tide lines perhaps)?

3. Preparation for the start. 
We should sail as much for the beat as we can to check on gusts and lulls, on wind bends and the effect of shorelines, etc. to decide what side is going to pay.

4. Up the first beat. 
If one side is paying, we should make a mental note to go that way up the next beat if the environment remains the same.

So, what are we looking out for when we go through these routines?

1. The Weather Forecast and Gradient Winds. One of the reasons that weather forecasts are only background help, is that the wind they describe is the gradient wind. This is the wind at about 500 metres up which is high enough not to be affected by the surface. However, it is the wind on the surface that we use and this is affected by surface friction. Not only is it generally weaker, but it is twisted to the left (in the Northern Hemisphere). The technical term for wind going to the left i.e. against the sun's direction, is "backed". If it goes to the right, it veers as it follows the sun's direction. Over water, where the friction is less, the surface wind is backed by about 10º. Over land and its increased friction, the wind can be backed as much as 40º over the gradient wind.

2. Wind blowing Offshore. As the wind leaves the shore, it will veer because of the change in surface friction. This gentle bend to the right can extend for some distance downwind. It can be spotted in our pre-race practice by checking our compass readings as we beat towards the shoreline. The wind increases in strength as it leaves the shoreline behind but becomes more stable as the difference between the gusts and the lulls becomes less marked.

3. Wind blowing Onshore. There will be no changes in direction on the water near the shoreline. Almost invariably, there will be less wind afloat than could be guessed at when standing on the shore.
 

4. Wind blowing along the Shore. If, when you are standing with your back to the wind, the coast is on your right,  the differing angles of the surface wind on the land and on the water increase the wind strength just offshore as they merge together. 
If the coast is on your left, the effect is the opposite as the two breezes separate and reduce wind strength for quite a distance offshore. 

5. Gusts and Lulls. Gusts and lulls occur in unstable air and happen when the surface and gradient winds become mixed up. This overturning of the air occurs as surface air heats up and rises, often forming cumulus clouds as it does. It is replaced by cold air being dragged down, bringing the stronger winds from above. As these hit the water, we see the typical darkening ripples. 
Interestingly, these gusts occur between the clouds. Underneath the clouds, the wind will be lighter because of the updraft. So, if at all possible, avoid sailing under them. Thus, if there are more cumulus clouds to windward on one side, head for the other side of the course.

6. Raining Clouds. These are usually darker than cumulus clouds. If rain is falling under a cloud, then air is being cooled. That air will be falling and the wind will be stronger. So, head for dark raining clouds.

7. Cloud base lowering to windward. This means a front (junction between a warm and cold air mass) is approaching. Winds increase as it gets closer. The appearance of the front is marked by heavy rain. Approach this on port, as the wind will have backed with the approach of the rain. As the cloud base rises behind the deluge, tack onto starboard because the wind will veer by as much as 90º!  In the unstable air stream afterwards (lots of cumulus), the wind will become blustery, and we're back into trying to stay away from the clouds!

8. Thunderstorms approaching with their typical anvil-shaped clouds. Obviously the forces creating this lot are pretty powerful. Air is forced upwards at an enormous rate. It is rapidly cooked and then blasts down to hit the water and fans out in very strong gusts. Hailstones only add to the misery!

9. Sea breezes. Sea breezes occur when the air temperature over the land is higher than the air temperature over the sea. This usually happens on a sunny day as the heated air over the land rises and drags colder air in from the sea. The air over the land then flows out to sea and, as it cools, falls to take the place of the air moving towards the shore. We can see the mechanism starting, as cumulus clouds build over the land, and clouds over the sea dissolve. As the sea breeze develops it turns gradually to the right, as much as 50 to 60º by mid-afternoon. This breeze dies away during the evening as the land begins to cool off.

10. Effect of Current. Weather flowing current - a current flowing against the wind - increases the strength of the wind that the boat is using. It also increases friction between the wind and water and so waves become higher, steeper with shorter distances crest to crest. These waves could slow the boat down somewhat, so it may pay to try and find flatter water even though that means there will be less weather going current. 
Leeward flowing current - a current flowing with the wind - reduces the strength of the wind the boat is using. Because friction between wind and water is reduced the water is flatter as the top of the waves is 'planed off'. Pointing is poor in these circumstances, and speed over the ground is very much reduced. It is a situation very much to be avoided if at all possible!

We'll never get all this right every time. But by working through things logically, we can dramatically improve the odds. It will not only improve our finishing positions but it will also enhance our enjoyment.

Happy Beating.

Auntie Alb