To My Friends in the UK I seem to have promised Steve and Simon that I would write an article on tuning a Sonar for your website. Since “tuning” alone is not enough to be useful, here are some of my thoughts on a number of factors that may improve upwind performance. I hope you find at least some of this helpful. Further, in an effort to counteract the current wave of American tribalism, I welcome any requests for clarification, or other discussion, either on your website forum or by email to [email protected]. Sheeting and Steering-Mainsheet and jib sheet trim are the most critical controls. In moderate conditions mainsheet wants to be trimmed so the upper leech telltale stalls about half the time. In light air you may want it to flow most of the time to maximize speed and get the keel working. In very heavy air you may not be able to keep it from flowing full time, which also helps drive through waves. Traveler should be adjusted so boom is on the centerline unless you’re overpowered. Every small puff opens the main leech and requires an immediate trim to restore the leech to its critical setting. Every lull requires an ease. Jib should be sheeted so all three luff telltales break at the same time but jib upper leech telltale should absolutely never stall. We do not cleat the jib sheet while sailing upwind, but always work to perfect its trim. In very light air I like to heel the boat to give some shape to the sails. I also drive it to keep the keel working. But as soon as it’s windy enough to get three or four crew on the rail it’s important to sail as flat as you can. Once you’re all fully hiked it’s ok to feather to keep it flat, although in chop you have to drive a bit more. I never sail the boat with more helm than you can easily deal with holding the extension with two fingers and a thumb. In breeze I ease the traveler as a shock absorber in puffs and bring it back up once we’ve feathered up. In very big breeze we sail with the traveler almost all the way down, mainsheet very tight, and ease the jib in big blasts to help keep the bow up, the helm balanced and the main from ragging. Crew: It is nearly impossible to be competitive through a range of conditions with less than 750 pounds of crew weight. I think 800 is better and Peter Galloway won a midwinter regatta with over 900 once but he was lucky it wasn’t a drifter. Mast-we go to great lengths to accurately control the stiffness of the mast so that when you sheet in your main to exactly where you want it to be forestay sag is exactly where you want it to be. This is a critical aspect to setting up a Sonar. Mast stiffness is affected by its age (sorry guys), any existing slop in the spreader-mast connection and the angle of the spreader bar. It’s pretty important that the spreader bar be angled so a taut thread across the uppers at the spreader tips is 2 3/4” to 3” from the aft face of the mast. Mast stiffness is controlled by partner blocks and shroud tension. Turnbuckles- We use Spinlock rigging screws on the forestay and four shrouds. They can be adjusted under load without tools, and they have a built in numbering system (each number corresponds to one turn of the screw) so it is easier to precision tune the rig. Sails- When I had the pleasure of sailing with Steve in early November, we found that when we rigged the old Banks jib with the small tack shackle and large clew shackle provided it was impossible to prevent the top of the sail from luffing. Unfortunately, we did not discover this until the first beat. Sonar class rules allow the lowest point of the jib tack to be 65mm off the deck. This can be achieved with about a 3-inch tack shackle, which you really must have. With a 3-inch shackle and the proper mast rake, the foot roach just scrapes the deck. Also, the clew blocks have to be very very close to the clew in order to sheet in the top of the sail effectively. Finally, I use North sails. Doyle seems to be just as fast and Quantuum is in there too. There may be other manufacturers that are equally tuned in to the Sonar program, but I know these three are fast. Rake-From zero to about 14 knots I set the rake at 25’11”. I measure it with the mast down, and engrave the corresponding Spinlock number on the deck. In more breeze I shorten the forestay—almost two inches less rake in 25+. That seems to be very fast, perhaps because it enables me to sail with less helm in heeling conditions. Keep in mind that shortening the forestay raises the boom (no big deal in traveler down conditions), raises the jib clew (which may require reevaluating jib lead position) and has the same effect as moving partners forward of the mast (which you want to do as the breeze comes up anyway). Making sure the mast is vertical-With no partners in place, I set the uppers just tight enough to not rattle around and the lowers just tight enough to assure the mast is in column. I use the backstay wire tied to a thin Kevlar line pulled taut to a mark on each toe-rail equidistant from the stem fitting and just aft of the chainplates to get the mast absolutely vertical. I engrave the upper shroud spinlock numbers on the deck. From this starting point, any adjustment to the uppers must be the same on both sides. Tuning- I look at Sonar tune this way: Mast partners control the amount of forestay sag and prebend; Shroud tension controls the life in the rig, i.e. how readily the forestay sags and the main leech opens in response to a puff or wave. The Sonar has an unusually lively rig. I am always striving to find the upper shroud tension that gets the forestay to respond dynamically in rhythm with the waves. That generally means that in light air they are quite loose (maybe four-inch circles in the uppers at rest), and as the breeze comes up they are tightened (maybe as much as 6-800 lbs. by the time it’s blowing 25+). In all cases I adjust the lowers while sailing upwind and sighting up the mast to achieve a 1/2” leeward sag at the spreaders. Partner blocks- I use a combination of 1/2”, 1/4” and 1/8” Delrin partners. I have found that a 1/8” partner adjustment can result in a noticeable difference in speed. It is important to set up a system so you can move partners easily while racing. We also modified the angle of the forward inside edge of the deck opening so it is parallel to the forward face of the mast. That keeps forward partners from popping out at random times. Basically, as you add partners behind the mast, the rig becomes more flexible so that for a given main leech setting you get more forestay sag. This gives you more power for light air. Conversely, moving partners to the front of the mast makes it stiffer and de-powers the boat. Because there are many variables affecting mast stiffness (age, spreader slop, spreader angle, precise butt location), information like “put 1 5/8” behind the mast with 25’11” rake in 11 knots” does not generally translate accurately between boats. However, here are some of the things I look for: Any time you feel you can use more power, more forestay sag is good until either of the following things occur: 1. When the forestay rattles around you have too much sag. 2. When the jib upper leech telltale stalls each time the forestay pumps, you have too much sag. As the breeze increases these symptoms become evident and require moving partners forward and perhaps tightening shrouds too. There is no getting around the fact that you have to learn your own boat. If you can make the time, it is beneficial to schedule dedicated tuning sessions with another boat. Make all initial settings as similar as possible, confirm that main and jib leeches are trimmed identically and that you’re sailing at the same angle of heel. Have one boat make one incremental partner adjustment at a time. If it’s faster then the other boat matches it. Repeat. Or, while racing, if your boat is set up so that you can move partners without getting off the rail or losing your lane then anytime you are going slower than a competitor in the same breeze try an incremental adjustment. When you suddenly find you’re sailing faster it feels very, very good. Dave Franzel expands on his Sonar tuning guide Following the publication of Dave Franzel's expert advice on fast Sonar settings and techniques, Steve Sleight asked him to expand on a few points. Once again, Dave very kindly agreed and generously shares his knowledge: Q:You refer to very light, light air, big breeze, etc. Can you put some Beaufort numbers around these please? A: You've definitely busted me here for using sloppy terminology.