Headsail setup
Is the sail cut to fit the boat, is the sheeting car in the right place, and is the forestay tension correct for the headsail to work?
I’m assuming the sail is correct for the boat and is a hanked on sail, roller furled sails would be the same except the halyard tension doesn’t change and once you put more than 4 rolls on the sail everything changes big time.
I’m a visual guy so, I’m going to describe what you should see in the shape of the headsail.
First lets look at the mainsails shape, in light to med air and close hauled release the vang and sheet the mainsail over top of your head while sitting at the helmsmen position. With the boom pointing over top the very corner of the transom and filled with wind, sight up the side of the boom and follow the leech of the mainsail all the way to the top of the mast. You should see the leech of this main bow outward towards the leeward side of the boat. The further up you look the more the pronounced curve as the leech goes to the top of the mast. Now, reach up and grab the backend of the boom and with the same line of sight start pulling down on the boom. You’ll see this curve at the backend of the sail get less and less as you pull down on the boom. Look at the very top batten, pull down on the boom till this batten appears parallel with the boom, if you pull to hard on the boom the backend of the top batten will start to point over the boom towards the center of the transom, you have to study it very closely to see it. When you see the batten is perfectly position parallel with the boom go to the vang and tension the vang till you see the same thing, the top batten parallel with the boom. Sheet the sail in closer to the center of the boat, do not sheet so tight to change its shape, use the traveler by pulling to windward. If the top batten is still where it should be, look at the back half of the mainsail from boom to top of mast from all angles on the boat, go to the bow and look at both sides of the sail.
This is what you want to see, the same shape in the back half of the headsail from bottom to top as you see in the main.
Tension the halyard with a few wrinkles in the luff under 10 mph and no wrinkles above 10 mph winds. Sailing close hauled, sight up the sheet line from the block to the clue and follow that line of sight to the sails luff or the front of the headsail. Position the sheet car so that a straight line would run from the car through the clue to the exact center of the luff. If this imaginary line goes above the center, the car is to far forward, then the sail will have extra power to go through the chop but, not as fast if exact center, to far back and below center will de-power the sail for high winds and not speed.
With the car in the proper position sheet the line in tight, so tight the sail almost comes in contact with the end of the spreaders on the mast, 3 to 6 inches is perfect. Sight up the leech of the headsail, does it look like the leech of the mainsail, if it had a batten would it be parallel with the outside edge of the boat, the top 1 third pointing straight back along the outside edge of the hull. The sail’s luff hanked on the forestay will be bowed forward and outward towards leeward. The more the bow in the luff the straighter the leech will be from bottom to top to a point. If you have 3 or 4 sets of tail-tells on the headsail’s luff and they are all flying then the tension on the forestay is correct.
Standing on the bow with the back of your head touching the forestay, look at the slot between the two sails. For this slot to be perfect at halfway up the headsail, the slot should look as though it gets smaller and smaller as it goes up, it needs to mirror the outside of the mainsail, if the slot looks like it goes up to the top 1 quarter part from the top and then starts to change more of the curve then the tension on the forestay is to tight. Have someone grab the backstay and push or pull as hard as they can on it while looking at the top part of this slot from the bow you’ll see this pronounced curve at the very top. Pulling on the backstay will increase tension on the forestay! Moving the sheeting car back towards the transom with also change this curve that you can see in the slot. If this curve is not even with the side of the main then the top part of the headsail is twisted out to leeward dumping air off the top of the headsail.
I have never tried this but, if you would make the forestay very loose and then attach a long line to the backstay in the area of the pigtail. Feed this line through the hole in the windward mooring cleat at the transom to pull the backstay sideways and pulling the other end of this line thus tensioning the backstay while standing on the bow, you’ll see the changes in the leech of the headsail and the slot as the tension changes on the forestay.
