Spreader angle

Before stepping your mast make sure your spreaders are the same length by measuring from the shrouds perpendicular to the side of the mast. The spreaders should be fixed in place straight out or slightly swept forward say 2 degrees. Also, place 2 tape marks on the spreaders 465mm and 555mm from the side of the mast. These are used to reference jib sheet tension.

Mast Position

The mast step position controls the pre-bend. Having the correct amount of pre-bend translates on the correct forestay sag, and therefore superior speed. Put simply the further aft your mast butt the more pre bend you will have and the more headstay sag you will see. With the mast butt forward the rig will have little or no pre bend and the headstay will fly much straighter with less sag.

This is what we recommend:

Fix or hold your tape measure on the transom at centerline. Measure over the top of the traveller passing to the side of the main console down to the back of the mast where it sits on the 'I' beam. This measurement for base set up is 5.36m.

The range of travel you will need on the mast butt is from 5.35m to 5.375m.

Mast rake

Once the mast is stepped, lay your forestay taught against the front of the mast, and mark the forestay at the point that corresponds to the upper edge of the black band on the mast at the gooseneck. Connect the headstay and set to a base length of 1.18m measured from the corresponding mark on the forestay to the deck. Before attaching the backstay, make a similar black band reference mark. Remember, that the measurements you are taking correspond to the top of the gooseneck band. The range of headstay movement we use is 30mm.

Upper & lower shroud position and tension

The upper and lower shrouds affect the mast differently. The tension on the uppers affects the fore and aft bend. Tight uppers (30 on Loos gage) will make the mast stiffer fore and aft, and loose uppers (22) will make the mast softer. The lowers affect the amount of middle mast sag (side bend). Having the correct amount of middle mast sag is crucial to proper mainsail shape and balance.

Think of the middle mast sag as similar to how the headstay sag effects the jib. More middle mast sag in light air powers up the mainsail, and less sag in heavy air helps de-power the mainsail.

You can tension the uppers to 23. Use your jib halyard to center your mast in the boat, checking side to side, before you continue with the tuning. When checking shroud tension, pull sufficient tension on the backstay (5 on Loos gauge) to remove slack in the headstay. To achieve base setting on the lowers tension to 7.

Final adjustment of the lowers should be made while sailing by judging the degree of mast sag. See the chart below.

	Caps (2nd Hole Aft)	Lowers (4th HoleAft)	Butt Position	Headstay Length (cm)
Wind Speed	Turns Added	Loos PT 2	Turns	Loos PT 2	cm	Top of Black Band
0 to 7 knots	None	13	0	None	535	120
8 to 12 knots (Base)	5	17	4	7	536	118
13 to 18 knots	7	23	4	13	537	117
19 knots +	4	28	3	19	537.5	117
	Full Turns		Full Turns

Mast Chocks

The function of the mast chocks is to adjust the bend in the mast for the conditions. Combined with the backstay and mainsheet tension, the mast blocks will control the bend of the mast and sag of the headstay, which helps the main and jib achieve a fast sail shape for the wind strength. When blocks are added in front of the mast, the mast bend is reduced, stiffening the mast for heavier air. This will have a great influence in decreasing your headstay sag. As the blocks are taken out from the front of the mast, the mast is allowed to bend which moves the draft aft in the main, and increases headstay sag. Bending the mast low down in the light gives the main a finer entry. The added forestay sag increases depth and power in the headsail. The additional depth in the headsail will probably mean that more rake i.e. a longer headstay can be used to maintain balance.

If the mainsail looks too flat, or the headstay looks too loose, producing excessive weather helm, the mast should be moved back at the partners or if not possible (because mast is always back at partners), then the mast step should be moved forward. If the mainsail looks full (round in the lower front area) and the headstay is too tight, move the mast forward at the partners or move the step aft.

The following chart is to provide a guide for the mast position in the partners when measured forward from the back end of the mast partner.

Backstay

The backstay controls the mainsail shape, the amount of twist in the mainsail and the amount of headstay sag you will have.

Before attaching the backstay, make a similar black band reference mark as you did on the forestay. After you have the backstay attached, measure down from the black band reference mark and make marks from 1.22m to 1.43m. These marks show the full range of backstay that will be played; the 1.22m mark is for very heavy winds and the 1.43m mark for super light conditions. The measurements in the table below provide a rough range of backstay adjustment for different wind velocities

Mailsail Settings

TWS	Traveller	Backstay	Top batten angle	Overhaul
0-6 knots	+275mm	1.4m approx	Open 3 degrees, tell tales stalling 50% of the time	30mm from band
7-11	+150mm	1.4m approx	Parallel to close 3 degrees, top tell tale stalled 30%	20mm from band
12-16	Center or +30mm	1.3m approx	Parallel to close 3 degrees, top tell tale flying all the time	Max
17-19	-100mm	1.25m approx	Parallel to close 3 degrees	Max
20+	-200mm	1.2m approx	Open 3-6 degrees	Max

Main Cunningham

Cunningham rarely used below 15 knots.
 
Jib Settings

Jib lead

The measurement for an average lead position is 2.6m from headstay at the deck to the middle of the jib car. To add power to the jib the lead can be moved forward as much as 30mm. Remember though, the lead position will have to be adjusted with any jib halyard changes. We have found that when the jib lead is set properly, the foot sets very flat.

Jib twist and sheet tension

We sail with two black bands on the spreaders as described in the "Rig set up" section. Measuring from the side of the mast along the spreader to the inside band should be 465mm. The outside band measures 555mm from the mast to the band. Using these bands allows the leech of the jib to be adjusted while looking through the spreader window of the mainsail, and increases sheet tension accuracy for different conditions. In light air, the leech of the jib should fall just inside the outside band. As the breeze builds the sheet tension will get tighter, up to the point where the leech of the jib is at the inside band. As the breeze and sea conditions build, the sheet will be adjusted to keep the leech between the bands. In 18+ knots the leech will line up with the middle of the outside band. In very gusty conditions you may want to be even further out to help keep the boat in control.

On all our jibs we have placed a leech tell tale between the two top battens. This leech tell tale, will help determine the correct sheet tension. For best performance, the leech tale should be on the verge of stalling at all times.

In light to medium conditions, for maximum power, the jib luff should have very little tension and some scallops should be noticed.

In breezy conditions, tension the luff quite hard to de-power and hold the draft forward.
Our latest North Sails jibs are made standard with "dual set of tabs" for added wind range and versatility. Using the long tabs will add fullness and allow for a tighter headstay in choppy conditions. As a general rule, if you are not pulling on the backstay to de-power, it is probably faster to use the long tabs
 
Spinnaker Settings

Rig setup while running

Getting the mast raked as far forward as possible is critical to downwind speed. Take out all the chocks in front of the mast after you get the spinnaker up. Ease the backstay off until the mast just rest on the front of the partners. The tip of the mast has moved through several feet, and the entire mast is now angling forward in the boat. To keep the mast from jumping around, it is common to have a separate piece of line attached to your jib tack shackle with a clip at the other end. Lower the jib to the deck, and attach the clip to the jib halyard shackle on the jib head. Pull the jib halyard tight.

Keep the inboard end of the pole approximately 800mm to 900mm above the gooseneck band. Under 8 knots of wind, the pole should be about 50mm lower at the outboard end. In 8 - 13 knots of breeze the pole should be about parallel to the water. In over 13 knots, the pole should be raised as much as 100mm at the outboard end.

Care of your Sails

Always store your sails away from the sun and make sure they are clean and completely dry. Be sure that you always "roll" your upwind sails. This will help then last longer and remain wrinkle free. If you have any questions or comments about our Etchells Tuning Guide, don't hesitate to contact us anytime.