Lark Tuning Guide by Sailboats Speedsails

The aim of this tuning guide is to help you get the most out of your Lark. Although the following measurements should enable you to set your boat up close to its ideal settings, it is worth bearing in mind that it is only a guide and minor alterations may be required for different boats and helmsmen.

Spreader Settings

The two measurements for spreader settings are length and deflection. Spreader length controls the sideways stiffness of the mast and is taken by measuring the side wall of the mast to the shroud. We recommend sailing with 470mm spreaders although very heavy crews may wish to increase this to 480mm to keep the rig powered up in breezier conditions. Spreader Deflection is measured by putting a straight edge from shroud to shroud and then measuring from the mast to this edge. This measurement is not critical as it is only a guide to getting the correct pre-bend which we check again later.

Setting	Parker Hull	Rondar Hull
Spreader Length (L)	398mm	380mm
Spreader Deflection (D)	155mm	150mm

Rig Tension

Hull	Rig Tension
Parker hull	~300lbs (26 on Super Spars Gauge)
Rondar hull	~280lbs (24–25 on Super Spars Gauge)

Increasing the rig tension reduces jib luff sag and straightens out the entry to the jib. This makes the jib point higher but less responsive to changes in wind strength and waves and therefore more likely to stall.

Mast Rake

Hull	Mast Rake
Parker hull	~21' 9" (6630mm)
Rondar hull	~21' 11" (6680mm)

To measure mast rake, hoist the jib with the appropriate rig tension and measure 18' to the top of the black band at the gooseneck. Cleat the main halyard and then measure the distance to the top of the transom. In heavy winds lighter crews should consider dropping the shrouds down one hole.

Jib Fairleads / Barber Haulers

Moving jib fairleads forward is equivalent to pulling the barber haulers on/down. The position of the jib fairleads affects the tension in the foot and leech of the jib. Moving the fairleads aft increases the tension in the foot and allows the upper leech to open (top windward tell-tale breaks first). Moving them forward decreases foot tension and closes the upper leech (lower telltale breaks first).

Conditions	Fairlead / Barber Hauler Setting
Light winds	Set pulley so the jib sheet bisects the clew at ~45°. Keep top of jib quite open. Top tell-tale on the inside should just lift before the bottom ones.
Medium winds	Keep jib sheets bisecting the clew at 45°. Move fairlead forward to stop the top of the leech blowing open. Sheet using top tell-tale as guide (just lifting).
Windy conditions	Continue moving fairleads further forward to maintain sheeting angle and control the leech.
Very windy	Move fairlead back to open the upper leech and prevent the slot getting choked. Ease the sheet if the mainsail is backing.

If in doubt, treat the fairleads/barber haulers as a kicker for the jib — as the main kicker is pulled on, move the fairleads forward; when the kicker is eased, move them back.

Mast Ram

Conditions	Mast Ram Setting
0–5 knots	Ram pulled forward to help flatten the main
5–10 knots	Ram in neutral position
10–15 knots	Use ram to straighten mast
15 knots – Racing Abandoned	Let the ram off 1 inch to bend the mast and de-power the sail

Kicker

In light winds you should only put on enough kicker to remove the slack from the system when sailing upwind. Once you start becoming overpowered and have to ease the main, aim to have the top leech telltale on the main flying approximately 80% of the time. In the Lark it is important not to use too much kicker as the mast is very flexible — look for diagonal creases from the spreaders to the clew of the main as a sign of too much bend. When sailing downwind, aim to have the leech tell-tale flying continuously.

Outhaul

Point of Sail / Conditions	Outhaul Setting
Upwind (all conditions)	Kept on tight
Upwind – light and choppy	Eased ~1" to give more power through the chop
Downwind / broad reaching	Eased 2–3" to give more power to the base of the sail

Cunningham

This should only be used in very windy weather to de-power the main. It should be the first thing let off when the wind drops.

Spinnaker

The spinnaker pole should be set so that the clews are at the same level as you are reaching along. We generally tie the head of the spinnaker so that it flies a couple of inches from the block in the mast. In a very light breeze when it is difficult to get the kite to fill, dropping the pole height will encourage the sail to fly again.