Jib (genoa) controls and adjustment

For this section, it would be useful to define light, medium, and heavy air sailing conditions.  It can be different for each skipper/crew/boat combination.  It is set by conditions sailing to windward:

  • light: The crew must sit inside the boat or to leeward to keep the boat flat.
  • medium: The crew and skipper can keep the boat flat while normally sitting or hiked on the side deck.
  • heavy: The crew and skipper cannot keep the boat flat without luffing, easing the sheets or flattening the sail shape.


1. jib halyard

  • Use 1/8 7 x 19 stainless steel wire to handle the high tension on the halyard.
  • Have an adjustable fitting between the top of the jib and the halyard to accommodate different sail sizes.  Small galvanized chain links work well and the appropriate number of links can be left on each sail.
  • Connect the wire halyard to a Highfield lever or magic box to adjust the jib luff tension.
  • To set the jib halyard tension, sail to windward and check if the leeward shroud is slack.  Tighten till it is just tight or, if necessary, loosen until it is just straight.
  • Another guide to jib halyard tension is the sag in the jib luff when sailing to windward.  There should always be some sag (approx. 2-3 at the middle of the luff) as compared to the vertical line of the forestay.
  • It is useful to mark the approx. settings for light, medium and heavy air so that rough adjustments can be made quickly when necessary.
  • Coil the rope halyard and fasten with a Velcro loop out of the way (on the side of the mast step).
  • Set the jib tack low enough so that the foot of the genoa will lie along the deck preventing air from flowing underneath. This escaping air will make the foot vibrate and reduce the power of the sail.
  • In light wind use the jib halyard to apply rig tension and some pre-bend to the mast.  Take up this tension on the forestay control line.  Then loosen the jib halyard tension until there is approx. 3 of luff sag.
  • If the genoa tack is not fastened to the bottom of the wire luff, it will be necessary to to install a genoa cunningham. This must be used sparingly trying to leave small horizontal "speed wrinkles" along the luff of the sail.


2. jib sheets

  • Install the fairlead track on the outside of the inside board on the front seats.  Use jam cleats with stainless steel jaws to positively grip the sheets. The fairlead jam cleat plate often gets bent down accidentally (stepped on!) making it hard to cleat when the crew is hiked out.  This can be prevented by installing a plastic or rubber spacer to the underside of the jam cleat and a spacer strip for it to rest on, along the top of the seat board just under where the jam cleat travels along its track.
  • The basic fore/aft position of the fairlead is set by running a string from the center of the jib luff, through the clew and extending in a straight line to the fairlead track.  This is a good guide to the correct position.
  • Install tell-tales along the luff of the genoa. Top one at 3/4 of the way up the luff, center one in the middle, and lower one about 25% from the foot. These are best made by using brightly coloured wool. Pull a strand through the sail cloth with a needle, then put knots on each side of the cloth to hold it in place.  Locate the tell-tales approx. 5 back from the luff wire and cut them to be 4. This prevents them from getting stuck around the front of the luff. Periodically treat them with anti-static spray.
  • When sailing to windward, set the mainsail sheeting. Then sheet in the jib until it slightly backwinds the main. Then just ease till the back-wind stops. When close to the correct jib sheet position very small adjustments make a big difference to performance.  A one inch change in sheet position will open or close the slot between the jib leach and the main by approx. 6 inches.  It also changes the relative tension in the upper and lower sections of the jib.  To fine tune the jib sheet adjustment, luff the boat slightly and check if the three windward tell-tales react evenly: If the upper one breaks first, sheet in slightly; if the lower one breaks first, ease the sheet slightly. The goal is to have all three tell-tales break evenly. Once set, the skipper should steer the boat by watching the middle tell-tale.  In the optimum position, it should be streaming backwards and slightly upward at an angle of about 45º.
  • It is useful to sew in brightly coloured threads into the jib sheets about every 2 along about a 12 section which is normally passing through the fairlead when going to windward. In this way you can learn which settings work well for different wind conditions, then use them as a guide each time you tack.
  • Do not oversheet the jib as this reduces the power of the sail and will slow windward speed. "When in doubt, let it out" is especially true as the wind drops to light air.  Ease the sails, bear off slightly and keep the boat moving.
  • In gusty wind conditions, ease the sheet slightly as the wind drops, then sheet in again as the next gust hits.
  • Install a tell-tale about 2/3 up the leech of the jib. This can be used as a guide to jib sheet tension. Trim the sheet until the tell-tale no longer flows straight out then ease it slightly. To use this continuously a window would be required in the luff of the main.
  • When going to windward in heavy air, the jib can be kept sheeted to a typical position for medium air (perhaps slightly eased). Then the boat is kept flat by luffing the sails as much as necessary. Ignore the tell-tales and just pinch up enough to keep the boat flat. This combined with hiking, flattening the main sail, easing the traveler, and perhaps slightly raising the centreboard provides good speed to windward. The real key is to keep the boat flat.