North Sails RESOURCES
Bullseye Tuning Guide
- Last Updated: February 8, 2018
- Tuning Guide (PDF)
The stable, safe Bullseye provides wonderful racing. Since it is a fairly heavy under powered boat, to get the best upwind performance the sails need to be trimmed so they are full and twisted in most conditions.
Spreader length and angle
Free Swing? Yes, should pull the shrouds in ½ to 1” from the straight line.
Is there any choice? No
HEADSTAY AND SHROUD TENSION
General, tight or loose: moderate to loose
To trim the main to best advantage rig a bridle. The object of the bridle is to enable the boom to be trimmed close to the centerline, without over tightening the leech of the mainsail. Rig the bridle by attaching a single block fixed at the center. Tie or run the ends of the line through the normal mainsheet blocks on the aft deck. When properly adjusted the length of the two bridle lines (equal on both sides of the boat) should hold the sheeting block just below the boom, over the centerline of the boat when the mainsheet is trimmed to make the top batten parallel to the boom.
To judge proper mainsheet trim, sight from under the boom, and trim sufficiently so the top batten is parallel to the boom. We recommend installing a head knocker type mainsheet cleat forward of the skipper’s position. Too little trim will reduce pointing and trimming too tight will increase weather helm and slow the boat. This allows the helmsman to adjust the mainsheet while keeping the boat on course.
Your North main has a lens shaped piece of light material fitted to the bottom of the sail. This allows easing the outhaul to make the bottom of the sail much fuller. In under 16 knots of breeze, ease the outhaul until the lens foot is completely open.
Sometimes, easing a little more works well too. When it blows hard tightening the outhaul flattens the main sufficiently to sail easily in 25 knots of breeze without excessive heeling.
Allow the lower half of the main to develop significant wrinkles. Tightening the cunningham to pull the wrinkles completely out pulls the draft in the main too far forward, and reduce pointing.
There are two important items here. Set the wishbone between the bottom hank and the second hank instead of the 2nd one. Use a light piece of line to support the wishbone at the half way point. This allows the top of the jib to twist properly, because the clew can rise up as the sheet is eased. The other point is there should be a telltale on the top batten.
The jib trimmer uses this telltale to determine proper jib trim which is just as critical to good speed and pointing as mainsail trim and needs to be adjusted more often.
When the jib is trimmed correctly, the telltale will just be flowing. To determine this trimming point, while the helmsman steers the boat on the wind, the crew pulls the jib in until the telltale flutters then eases it out until it flows again. It is helpful when speed drops coming out of tacks or when sailing into bid waves, to ease the jib sheet. Paying close attention to the leech telltale helps determine how much ease is best. The helmsman needs to steer the boat so the weather telltale on the luff of the jib lays down, but when the leeward telltale flutters, the sheet should be eased until the boat can be headed up again.
Clew position is determined by the wish-bone setting.
Be careful not to over tension the jib halyard. Set it so there is a slight hint of horizontal wrinkles in the jib luff. In a breeze these will show up at the hanks. In lighter air they should show evenly along the luff tape.