North Sails RESOURCES
Y-Flyer Tuning Guide
- Last Updated: August 23, 2017
- Tuning Guide (PDF)
Congratulations on your purchase of North Y-Flyer sails. We are confident you will find superior speed over all conditions. Your sails are designed to be fast, as well as easy to trim and handle.
The following measurements are those we have found the fastest for your new North sails. After experimenting, you may find a slightly different setting may mean even better boats speed for you. We are anxious to help you go faster and win races!
Mast Placement – The mast step should be positioned so that the mast is near maximum aft position. In this position the back edge of the mast should be 16” to 16½” forward of the centerboard pin.
Mast Rake – the best method for measuring the mast rake on the Y-Flyer is by hoisting a 50’ tape to the top of the mast and measuring the distance from the top of the mast to the intersection of the transom and the back deck. Just hook the tape on your main halyard shackle and don’t worry about adding or subtracting any difference for the shackle. With the rig tensioned properly (discussed later) this measurement should be 24’1” to 23’10½”.
If you are trying to correspond this measurement to the older method of the bubble level on the top of the centerboard trunk, the measurement should be approximately 30”-31”.
While the tape measure is hoisted to the top of your mast it is important to check that your mast is set up straight in your boat laterally. To check this, take the tape and measure the distance from side to side at the bottom of the chainplates. Try to adjust your shrouds so there is no more than ¼” to ½” difference from side to side.
Rig Tension – We have found that the Y-Flyer performs best in medium winds with the rig set up fairly tight. It is best to use a powerful jib halyard adjustment system (a lever, magic box, block and tackle, drum, etc…) so that the leeward shroud just begins to go slack when it is blowing 10-12 mph.
To verify the proper rig tension we strongly suggest using the Loos Tension gauge. When using the Loos gauge, and checking the tension on your 1/8” upper shrouds, the number should read approximately 34-36 (not lbs.).
In light winds without changing the shroud position, it is advantageous to ease off the jib halyard slightly so the tension is reduced in the rig. This will allow the jib luff to sag slightly, making the jib slightly fuller. Using the Loos gauge to check the tension on the shrouds, you should find a number of approximately 28-30. If you still have your tape hoisted on your main halyard, you can check the rake number and see that it will become less (indicating more rake) by 1-2”. In heavy winds, when the boat is overpowered, it is fastest to rake the rig farther aft. If you set your mast up at 24’1” for medium winds, we suggest that you allow it to drop back nearly as far as 23’9” to 23’10”. Ideally, it is best to also drop the shrouds in their channel adjusters so that the rig, when raked farther aft, would still be close to the proper 34-36 Loos gauge number on the shrouds. However, if the breeze comes up during a race and since it is impossible (and Illegal!) to change the shroud tension it is still best to compromise and sail with a looser rig with the mast raked farther aft.
Loos Tension Gauge – This gauge is a very helpful guide in tuning your Y-Flyer.
Mast Bend – when the rig is properly tensioned with the proper rake and spreader settings, your mast should develop positive prebend, where the middle of the mast will move forward at the spreader and the top of the mast will come aft. In medium winds with the rig tensioned at 34-36 on the shrouds the mast should develop nearly 1” to 1½ of prebend. You can check this by pulling the main halyard down tight and holding it at the gooseneck so it will develop a straight line as a reference from the top of the mast to the gooseneck.
In light winds with less tension in the rig, there will be less prebend of approximately ¾”.
Listed below are suggested spreader positions for the various popular masts used the Y-Flyer Class. It should be noted that masts of a particular section may have slightly different bend characteristics depending on spreader height and rigging placement and differences in the extrusions themselves. Because of this, the following measurements should be used as starting points only with appropriate adjustments being make on the actual bend and tested while sailing.
Spreaders for the stiffer mast (W2, H2) – We have found that the spreaders that are 19¼” long and are free swinging forward but lock up when pushed aft at a point where they are 35” to 36” tip to tip will give the proper desired bend. this tip to tip measurement can be found by pulling the spreader together with a tape from one spreader to the other at the tips. Also, check and make sure that the spreaders are angled evenly on each side. These measurements are for masts with spreaders that are 9’1” to 9’2” from the deck. Spreader that are higher on the mast will need to be somewhat shorter.
Spreader for the bendy mast (DP1, C1) – These masts require spreader which are 18 ½” long and 38” measured tip to tip. These measurements are taken of masts when the spreader are approximately 10’ above the deck. To make adjustments to the bend, the “cant” in the spreader should be adjusted (forward for less bend-aft for more bend: or closer tip to tip measurement for more bend, greater tip to tip measurement for less bend).
The Mainsail Look When the Mast is Properly Bent: Basically on all masts we are looking for very slight overbend wrinkles (diagonal wrinkles that will appear from the spreaders to the clew) showing that the mast is beginning to reach maximum mast bend. In light to medium wind these wrinkles should barely appear while in winds above 15-18 mph, these wrinkles will be quite noticeable and in above 20-25 mph winds, will be quite severe. If these wrinkles are not developing, your mast is not bending enough.
Lower Shroud Tension – Your lower shrouds should be adjusted so that the mast is straight sideways when sailing upwind. Check this by sighting up the back of the mast, up the tunnel, and determine if the mast is sagging to leeward or bowing to windward at the spreaders. If sagging to leeward, tighten the windward lower shroud; if bowing to windward, loosen the windward lower shroud. Check both sides independently and when adjusted correctly the lower shrouds will be much looser that the upper shrouds with the jib up and the rig tension as described before.
If you find that it is necessary to sail with your lower shrouds quite tight to keep the mast straight sideways, it could be a good indication that your spreaders are too long. Lower shrouds that are tight can severely impair the mast’s ability to bend properly and therefore harm the boat’s performance. Shorten your spreaders in increments of 1/4” to 3/8” and readjust the lower shrouds to match. Again, your goal is that the leeward lower shroud will be much looser than the leeward upper when sailing upwind in medium winds. The lower shroud should be considered just as a “tweeker” to help control lateral mast bend, but definitely not to be the primary control. The spreaders are most important.
Jib Lead Placement – On your new North Y-Flyer jib you will notice a pencil line drawn from the clew grommet out towards the center of the sail. Use this “trimline” to position your jib lead by making your sheet a direct extension of this line.
In heavy winds, move your jib leads 1” to 2” aft of your medium/light air extension of the trimline position to help depower the jib and open up the slot.
Your leads should be positioned 13½” to 14” off centerline (27” to 28” lead to lead).
Centerboard Angle – It is important that your board is lowered to the maximum, with as little of the board as possible showing above the trunk when sailing upwind.
Main and Jib Cunningham – For both the main and the jib, never pull tighter than to just leave a hint of wrinkle along the luff of both sails. On your main, these wrinkles will appear in the lower 1/3 to 1/4 of the luff, and on your jib, will appear as small wrinkles approximately 2” long, perpendicular to the luff.
Note: do not attempt to pull out your overbend wrinkles by tensioning your main cunningham. Again, remember that the overbend wrinkles are a necessary guide in showing that the mast is vending properly and pulling the cunningham tight enough to pull these wrinkles out will pull the draft too far forward in your main, robbing your boat of necessary power.
Outhaul – The outhaul adjusts the depth in the lower part of your mainsail. as the outhaul is eased, the shelf on the bottom of the sail opens and the seam that attaches it to the sail moves away from the boom. To gauge outhaul tension, judge the distance from the seam to the side of the boom at roughly the center of the mainsail foot.
The outhaul will be pulled tight enough so that there is just a ½” to 1” gap between the side of the boom and the shelf foot seam in the middle of the foot. In breezes above 10-12 mph when the boat becomes overpowered the outhaul will be pulled tighter until the seam is snug against the side of the boom (max outhaul).
When reaching, ease the outhaul until vertical wrinkles appear across the seam perpendicular to the foot into the body of the sail. Tighten your outhaul until the wrinkles are just removed. When overpowered on a reach, with the spinnaker, leave the outhaul set as you had it upwind. For downwind sailing, leave your outhaul in the tensioned position for maximum projected area.
Jib Sheet Trim – Unfortunately, there is not an easy guide for jib trim. We are looking for a parallel slot between the exit of the jib and the entry of the main. A guide that has been used with some success is imagining a middle batten on the jib at mid leech. Set this “batten” parallel to the centerline of the boat, making the upper batten of the jib twist outboard slightly and the lower batten twist inboard slightly. In extremely flat water and winds of 8 to 12 mph, it is possible to trim the jib in slightly tighter so that the top batten is nearly straight back parallel with the centerline. This trim can be used for short periods of time when the boat is traveling at near maximum speed.
In light winds, or when acceleration is needed, ease the sheet out slightly so that the top batten is angled outboard approximately 15 degrees from parallel with the centerline of the boat. The imaginary middle batten will be angled outboard just slightly from parallel to centerline, and the jib will be fuller and less apt to stall.
Mainsheet Trim – The mainsheet on your Y should be pulled so that the upper batten is parallel to the boom. This is sighted underneath the boom looking up the sail, lining the batten and the boom parallel on a horizontal plane. In very light winds, it is usually impossible to keep the upper batten from hooking slightly to weather because of the weight of the boom hanging on the leech. In these conditions, ease the sheet out so that the top batten is parallel with the centerline of the boat.
In choppy conditions in winds above 2 to 3 mph, ease your mainsheet approximately 6 to 8 inches to slightly open the upper batten out from parallel to the boom. This will make your mainsail fuller, more powerful, and like the jib, less apt to stall.
In medium winds and flat water (ideal boat speed conditions) sometimes it is possible to slightly overtrim your main so that the top batten is looked to windward of parallel to the boom approximately 2 to 5 degrees for short periods of time.
Picture the mainsheet as your accelerator. As your boat picks up speed, pull the main tighter and tighter until the upper batten is parallel or slightly looked to the boom, and in lights winds or when the boat is hit with a wave and needs to accelerate, ease the mainsheet so that the upper batten will angle outboard slightly, inducing “twist” into the sail.
Boomvang – Upwind in medium to heavy winds the boomvang should be kept hard enough to keep the upper batten parallel to the boom. This may require a good deal of boomvang tension, but this will also help to bend the mast and flatten the sail. In light winds, never use any boomvang tension upwind. Downwind the vang should be tensioned only tight enough to maintain the upper batten parallel to the boom position. There may be a tendency to overvang downwind in light winds and undervang downwind in heavy winds. Basically, look for the main to set downwind as it does upwind. The traveler is used to help balance the helm of your Y and keep the boat upright. Upwind when the boat becomes overpowered, the traveler should be eased to leeward, with the boat slowly feathering up into the wind to help keep the boat level and the helm neutral. In the lulls, be sure to quickly pull the traveler back up to centerline, but be ready to ease back down to leeward in the puffs.
Downwind – When sailing your Y downwind with the whisker pole up, it is best to ease off your jib halyard as much as 10” to allow the luff of the jib to sag greatly. A loose luff, when sailing with a pole, will allow the jib to basically “turn around” with the leech becoming the luff and the luff becoming the leech. We need to remember that we are trying to create airflow across the jib with the wind entering the jib from the actual leech of the sail. Not attaching your jib to the forestay with the snaps or Velcro’s will make this procedure much easier. Instead, you can set the forestay so that it is loose enough to just allow the rig to lean back to your heavy air setting of approximately 23’9”. There will be slop in the rig, but that is necessary for top performance downwind. A shockcord retainer can help minimize the slop in the headstay when sailing upwind.
In addition, it is also suggested to sail with a longer whisker pole, which will help with better performance on beam and broad reaches. You will find that the pole will just barely fit in the cockpit of your boat!
Once again, a powerful jib halyard adjuster is helpful to make it easy to adjust the halyard tension properly and easily before rounding the leeward mark when the pole is dropped.
When sailing on a close reach, without the pole, be sure to use your barberhaulers and move your jib lead outboard. The proper position of your barberhauler lead, forward and aft, is determined by the trimline on the clew of the jib. This time, position the barberhauler lead so that the sheet is angled slightly forward of parallel to the trimline. This will make the jib slightly more powerful and help to support the upper leech.
We wish you good luck and fast sailing! Do not hesitate to give us a call if you have any questions or problems. Please consider us your personal sailmaker.