Setting the sails for the conditions

To my mind the foot is set far to flat on this mainsail for the conditions- Alan Hayes Photo

Step three

Perhaps one of the things I get asked the most is, how much shape should I put in the foot of my sail? Probably every top sailor has a different opinion on this one, so all I can do is suggest the settings I consider the best, and these are obviously going to be orientated around the design of my own sails. And this is important to note, as the fullness or shape cut into a sail will dictate in the end how much foot shape you might want to set the sail with!  Obviously wind strength is the other main factor, so first we shall consider light winds of less than 5knots.

The Jib

In 5knots or less you need all the power you can generate, some consider that the sail needs to be rather flat in these conditions so as not to stall the wind flow around the sail, I don't! I think sail shape or draft creates drive and dive or power will get your boat moving faster in light winds...works for me! It might pay to note here I do not cut very much shape into the top half of my jibs..why? because as the wind gets up, the forestay sags, you can't stop it all, and it adds a lot of shape to the top section of your jib, if you start with a full top half you're going to have a bucket up there in over 10knots! So if your jib is a little flat cut as mine are you do need to induce quite some amount of foot round, to generate sufficent drive in the light, anything up to 30mm is acceptable as far as I'm concerned. Coming back to 20mm as soon as there is 5knots or more, how much flatter you want to go after that could depend on the design of boat you have, I only flatten the foot right out if I'm carrying the A rig in conditions that suggest I should have the B rig on! A point to note; usually on a gusty day the wind gusts up only about 50% of the time you are on the wind,  sometimes even less than this, most of the other 50% or more on the  wind you will be under powered if you have flattened your sails right. Down hill you will also suffer from lack of power with flat sails, gusty or not. So if you work it out, over flattening your sails only gives you an advantage for 25% of the race, which means you could be underpowered for 75% of it, this is something to think about before you go overboard flatting sails on windy days, better to let the leech twist off a little more and keep some power in your sails, because gusty days usually mean choppy sea conditions which require power in the sails to drive you through it.

The Mainsail

What applies to the jib generally applies to the main, I tried flat mains they did not work for me! The jib is a little different because it gains fullness due to forestay sag but a main does not, if a main is cut flat it will stay flat, so I have started to build more powerful mainsails of late because it is easier to flatten a main than make it full, and a little mast bend helps with a more efficent elliptical profile as the breeze gets up. Even so with a more powerful main I still seem to have more speed in light conditions with a lot of foot round induced. As much as 20mm seems to be a go in light conditions, coming back to 10mm in over 5 or 6 knots, don't be afraid to experiement, these figures are only suggestions your boat, sail, combination may well respond to different settings than these.

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