PRESENTED BY LENAM FOR THE BENEFIT OF THE CLASS

There are two variable to take into account, the length and the aperture or deflection. The length is measured from the sidewall of the mast to the shroud. The deflection is measured from an imaginary line joining the shrouds to the after end of the mast.

The length is normally determined by the weight of the crew, shorter for light crew, longer for heavier crew. Short spreaders will more readily allow the mast to bend sideways than long ones, causing the upper part of the main sail to open up 45cm for a light crew, and 50cm for a heavy crew. A good length for the spreaders is 48cm.

You can expect that with little or no halyard tension on the jib, the luff will fall away to leeward causing loss of windward performance and will close the jib leech.

WINDSPEED RIG TENSION SUPERSPAR GAUGE

0-6 knots        123 Kg. 270 lbs. 24

6-l0 knots        136 Kg. 300 lbs. 26

10-20 knots 155 Kg. 340 lbs. 28

The chocks allow for variable control of mast bend depending on sailing conditions. This is crucial for controlling the amount of power in the rig.In light airs and a flat sea, no chocks are needed. In this way the mainsail will present a better profile to the wind without closure of the leech.

With stronger winds, one or two chocks of 15 mm should be used to prevent the mainsail stalling when using the kicking strap, however if the luff of the mainsail is too full shocks will have to be removed.

WINDSPEED CHOCKS

0-6 Knots        0

6-10 Knots    2

10-14 Knots 2-3

14-20 Knots 1-2

The mast rake is set with the chocks in place and the jib tension adjusted for the conditions prevailing. The tape measure is attached to the main halyard and hoisted to the upper point of where the mainsail is permitted to be set, the measurement of the sail is to the top centre of the transom.

WINDSPEED MEASUREMENT

0-10 knots        606cm.

10-18 Knots 603cm.

18 + knots        597cm.

CUNNINGHAM - This should be loose in light airs, disregarding slight horizontal creases, as the wind force increases it should gradually be tightened, moving the air flow forwards and flattening the leech. This effect will also reduce the heeling moment.

FOOT TENSION - Increased tension will flatten the lower part of the sail. It should be fairly tight with flat sea conditions and slacker with waves and so increase the power of the mainsail. Off the wind it should be quite loose.

First adjustment is the height of the jib. The most effective way is to set the rake and rig tensions required for the conditions prevailing and then place the boat on its side. Take up on the jib sheets and adjust the jib height so that the foot lightly touches the deck, tension the sailcloth so that the creases are removed. In view of the fact that the fairleads are fixed, the only other adjustment possible is by increasing or reducing the mast rake. With greater rake it will be important to raise the jib somewhat higher, or lower, with less rake and so prevent excessive opening of the jib itself.

BARBER HAUL - As the fairleads cannot be closer than 1250 mm, the jib remains quite open. In order to control this, pulling on the leeward jib sheet can only do it. To pull the sheet too hard will not improve the performance.

Indications of excessive barber hauling are backwinding of the mainsail and, looking from the lee side, the position of the wind flow over the jib.

For best adjustment it is best to have tuning sessions with another boat and make note of adjustments and the result.

A rigging adjustment will have to make bearing in mind the wind and sea conditions prevailing or expected, depending on your point of view and perhaps your faith on the forecast.

We hope that these instructions will prove effective for you to obtain maximum speed and enjoyment of your sails. If you have any doubt don’t hesitate to contact us

IBI Racing Sailboats

The Old Mill

Birdham Pool, WEST SUSSEX. PO20 7BG.