Tuning by Alan Simmonds

SETTING UP, TUNING AND SAILING
A few thoughts on how to set up and make your Streaker go faster during the following season. Please bear in mind any measurements etc. are not 'cast in stone', and may require tweaking for individual circumstances.

Mast Rake

With the mast stepped in the hull (and rigging tensioned sufficiently to remove slack at the shroud pins without bending the mast forward measure the distance from the aft face of the mast to the front of the daggerboard case. This should be 2'2" (660mm), level with the mast heel. If it is less the mast stop may be too far aft. Using the main halyard, hoist a tape to a point level with the bottom of the mast upper band. The tape should indicate a measurement of 20'1" (6.120m) to the top of the centre of the transom (see "Rig Set Up"). This setting (mast tip to transom) is a starting point and should be adjusted - more rake for better pointing up wind, less rake for better off wind performance. Only adjust small amounts at a time, keeping that setting for several races in differing conditions. Ensure that the shroud adjustment devices have sufficiently small increments to permit this - if you use single line holed plates, just move one hole at a time and recheck the distance.

Main Halyard

The sail must be raised to its maximum possible height (lower edge of the upper black bank) and tacked down to the top of the boom. Tension on the luff of the sail must not be sufficient to generate vertical creasing just aft of the mast - use a wire halyard and hook rack for stretch free and locatable hoists.

Outhaul
For medium wind strengths (force 3 to 4) the sail should initially be set such that, at the point of maximum draught there is a gap of 6" (150mm) to 8" (200mm) between sail and side of boom, level with its top. For very light or strong breezes the foot of the sail should be outhauled until the foot is tight, even with a strong horizontal crease. The amount of tension applied to the foot will only be found with experience. Progressively ease the foot on offwind legs but not beyond the initial setting - mark either the control line or use measuring strips on the boom for the position of the clew of the sail.

Cunningham
This control should be used sparingly to remove horizontal luff creases in light to moderate breezes and then progressively as the wind strength increases. It can usually be released on the offwind legs, as these become broader - apart from removing horizontal creases the purpose of the cunningham control is to bring the sail draught forward as it is blown aft in increasing wind strengths.

Kicker
This controls the mast bend, via the sail, and as a consequence also sail twist. It should be used with caution, not too much and not too little depending upon the point of sailing and the wind strength. Upwind in moderate breezes apply lightly - the mainsheet will also bend the mast so do not over tension. As the breeze increases and possibly you feel that you are being overpowered apply more. Offwind, let it off, but do not allow the boom to rise unduly or risk a chinese gybe - when the wind gets ahead of the sail - sail twist is a science in its own right, suffice to say that a closed or hooked leach will cause the sail to stall whilst an open leech will allow proper separation and smooth flow off the sail.

Traveler and Mainsheet
The primary sail control, like all others should never be used to excess. Upwind on the beat it should not be hauled 'block to block' (as in a Laser) assuming that the traveler is fairly tight. If it is too tight, diagonal creases will emanate from the clew toward mid mast height. Not only does it look messy, it can do nothing to improve smooth flow across the sail. For upwind sailing the mainsheet should be pulled in to bring the boom aft and vertically above the leeward corner of the transom. In light conditions this can be achieved by easing the traveler and only gentle application of mainsheet - for upwind sailing in all but the lightest of breezes use a centre mainsheet jammer to cleat the main. Offwind, hold the sheet between the jammer and the boom take off block. For the hardy
amongst you with just ratchet blocks or the sheet led from a block on the traveler just keep the ratchet of offwind.

From Streaker Newsletter the contents are extracted from a previous article written by Alan Simmons.