The Butterfly Basic Tuning Guide

By Jim Young

The Butterfly is easy to set up, and forgiving of a wide range of adjustments. What follows is a basic guide; there are some experienced sailors who set up a little differently, but their speed with those set-ups is a result of practice and experience, not the tuning alone.

Starting with the hull, as with any modern fiber-plastic boat, it is best to keep it clean and smooth. Whether to wax or not is up to the sailor. A waxed boat will stay cleaner, and thus sail faster, in dirty waters, and will be easier to slide on and off shoreline docks. If the boat is not waxed, it should be cleaned regularly with a fiberglass boat cleaning compound. Experts may argue about whether waxing or a clean wet-sanded hull (with #600 wet/dry paper, using lots of water to keep it wet) is faster; in a boat as small as a Butterfly, it does not matter which is done, as long as the hull is clean and smooth. (Wet sanding with #600 paper is also the way to take out the normal small scratches that appear over the years, and to keep the hull smooth.)

The centerboard needs a little attention. The goal is to have it clean and smooth, just like the hull, so wet-sanding is the usual answer. If it gets minor dings or the edges chewed up, especially the trailing edge, touch up the finish with a good marine varnish and wet-sand when its dry. You may have to start out with #400 paper used wet to fair in the new varnish to the old finish, but finish off with #600. On major dings, use a polyester boat putty filler, sand smooth and varnish over it. If the boat hums a lot, it is from vibration of the board. This is not caused by the board, it is because of lumps and bumps of gelcoat just inside the bottom of the boardbox. Use a flat file on bad lumps, then find someone with skinny fingers to sand inside. It is not necessary to get far in, the problem spots are usually in the first inch.

The last part of the boat in the water, the rudder, is of aluminum, and generally needs little attention other than keeping it clean. It is virtually never waxed. Sand out little dings or dents on the edges. The most important edge is the back edge, keep it straight, clean, and the corners of the flat edge sharp. Don't try to sand the back edge to round or taper it; not only is it not allowed under the rules, a small square edge with sharp corners will be technically faster. Other rudder details; if it kicks up too easily, or not at all, tighten or loosen the center pivot bolt. First loosen the nut, then use a screwdriver on the head, but go easy, it usually only takes 1/2 turn to make a big difference. Remember to tighten the nut when done. The last item is the pivot assembly; if you sail regularly in salt water or off a fine sand beach, flush the pivot area regulary with fresh water.

The boat normally sails with both the board and rudder blade all the way down. The rudder says down all the time, but the board is changed for different angles of sailing. When going upwind, it is all the way down in all winds, unless the sailor is a real light-weight and is feeling over-powered. Then pulling it up a bit, 2 or 3 inches, is another way, along with flattening the sail, to de-power. When reaching, up 6 inches or so is usually good enough. For downwind, it should be only up far enough to still fill the bottom of the board box. Pulling it up more is usually a mistake, opening that big hole in the bottom of the boat is slower than keeping a little bit of board sticking out from the hull. That little bit of board also helps with downwind steering. (Hint: Tip the boat over on land and put the board in, with the curved edge forward. From the bottom, push the board up until the curve of the board just begins to disappear into the slot. Then go around the the top of the boat and make a magic-marker line on the board at the deck line. Never pull the board up beyond that line.)

Getting to the top of the boat, the tiller handle is no problem, just keep it varnished to look nice. If it rubs on the deck, take a look underneath the handle where it fits the rudder head; there is a small nylon spacer there. Either pull it off and put a stainless steel washer underneath it, or for a quick fix, put a couple strips of tape over the rudder stop where the nylon spacer hits. The tiller extension is an area to pay a little attention to. I prefer an extension longer than standard; the nice little adjustable ones are great. The reason is not to hike harder in heavy air, it is to allow the skipper to get more forward in light air. Careful with the length, if it is too long it will hang up on the bridle wire or mainsheet. (Hint: If you use an adjustable extension, mark the shaft with tape at the length where the extension can go back to - but not past - the bridle, and never let it get longer than that so it does not foul in the bridle or sheet lines.)

The hiking strap is a bit unconventional. When the boat was first designed, hiking straps did not exist in small boats, and the hand rails that are in the cockpit were actually intended as toe rails. When somebody finally figured out how to add the strap, it was a simple addition - except the strap goes across the cockpit instead of the long way. Its actually easy and confortable to use, once you get used to hooking your ankle under it. Set it up so that it is tight at the front end of the toe rails, and in light air - or sailing with two or more on board - its easy to slide it aft and out of the way.

Now for the mast. First, with it on the ground, check the side stays to be sure they are the same length. If they are not, don't panic to change them, just set the stay adjusters on the sides to different holes to compensate. Now, set the boat flat, on a trailer or sawhorses or block it sitting on the beach or lawn. Flat means having the rubrail horizontal. With the boat in this position, the mast should stand straight up when looking from the side. If you are a nut for measurements, tie a weight to the main halyard to use as a plumb bob, and it should hang along the mast. The controlling adjustment is the forestay. When the mast is vertical, adjust the side stays so that the mast can just be rotated to 'almost' 90 degrees. This will be fairly tight, you may need someone to push on the mast to get the last adjuster pin in place. Don't get paranoid about this set-up process, a hole or two off on the adjusters will make no noticeable difference for most sailors. If you make a mistake, try to be more aft that forward with rake, going forward from vertical produces some very unpredictable rudder actions!

The mast rake is where there is the biggest difference among the boats. And this is where skill and experience fit in. As the sailor gets better at boat handling, the mast rake aft can be increased. This allows for the potential for more speed. BUT this speed can only be realized if the boat handling and sail handling are good. Unless you have really good skills - that means a very good feeling for how both sail trim and angle of heel affect rudder pressure - in all winds, it can be a big mistake to rake back more than a couple holes on the adjuster. Any increase in rudder pressure will only slow the boat down.

Now the sail. When the mast went up, the main halyard should have been in place. There is a hook molded in the front of the aluminum mast head on older masts, or a black clam cleat on newer ones. With the hook, use a knot in the halyard to hold the sail up. With the boat on land, tip the boat over to look at this hook/knot arrangement, and also at the top of the sail. Make a mark on the halyard where the sail has to be tied in order to get the sail all the way up to the top of the mast when the knot is in the hook. (Hint: Tie a second knot in the halyard, about 4 inches from the first, and use this knot in the hook in strong winds to lower the sail. It makes the boat much more controllable in strong winds. BUT this trick is not race-legal, just something to use to keep the boat a bit easier to control in more extreme conditions.) For masts with the clam cleat, its easier, simply tie the halyard on the head of the sail with a good knot, hoist the sail, and lay the halyard in to the cleat. For strong winds when you are not racing, simply don't hoist the sail all the way.

The sail controls are the out- and down-hauls, the boom vang, and the mainsheet. The 'hauls' first; both are set too tight by most sailors. Adjust until there are no wrinkles when sailing, vertical wrinkles above the boom for the outhaul and horizontal wrinkles off the mast for the downhaul, then EASE them both a little, so that wrinkles just begin to appear. These adjustments are made while sailing, not sitting on the beach. Lighter-weight sailors should have the outhaul tighter, especially as the wind increases, and the downhaul should be only used if the sailor is feeling overpowered and is fighting the boat. (A Really Big Hint: Pulling the mainsheet harder flattens the sail - by bending the mast - much better than pulling on the downhaul.) And a note for those of you who like to fiddle with lines, I virtually never touch these controls once a race begins. To make that point clear to a training camp group before a big regatta, I once rigged my boat without any downhaul line at all - and then won 5 of the 7 races in the event!.

The vang is not the same as a vang on a boat with a non-rotating mast. It should not be set too tight upwind, because it prevents the mast from rotating. There are a few sailors who have had success with the vang tight and no mast rotation, but to make this work they have to take great care to keep the sail full by actually pushing up on the gooseneck and then never touch the downhaul. This way of sailing the boat is also extremely sensitive to steering and can stall very easily. The vang should be set snug for a reach, and tightest, but not super-tight, downwind. To set the vang for a downwind, tighten it when sailing upwind, BEFORE going on a reach or downwind. Likewise, it is loosened going upwind, AFTER the reach or run. It should be freed enough to allow the mast to rotate, not more. If the vang is too tight upwind, the mast will not rotate when tacking.

The mainsheet is the basic, and most important, speed control. When and how much to adjust it is gained from experience more than anything else. In general, it should be tight upwind, enough to bend the mast a little in moderate wind. In light wind, the sheet should be eased so that the back of the boom is over the leeward corner of the transom. In heavy wind, sheet harder and harder until overpowered, then free it enough to keep the boat flat and under control.

For angle of heel and body position, in heavy air all the weight should be as far forward in the cockpit as the hiking straps will allow going upwind, and as far back as possible on reaches. Downwind, the weight needs to be forward, but carefully, so the bow does not bury. An exception to weight forward upwind is in waves, when the weight needs to be far enough back, up- and down-wind, to keep the bow out of the next wave - in the photo on the left, the sailor is too far forward for the waves, and the bow digs in too much. But notice his good hiking style!. In light wind, in general, the weight should be forward all the time, up on the deck just forward of the cockpit. Since the ideal is just not possible for most body shapes, as far forward as is comfortable will do. In moderate winds, front of the cockpit up- and downwind, and middle on reaches.

With heel, the Butterfly requires compromises. The scow hull sails best heeled over about 15 degrees, but at that angle, the Butterfly's centerboard is sideslipping badly. So the answer is to keep the boat as flat as possible upwind in all moderate winds, heeling only a little to get through waves. In light winds, a little - repeat, LITTLE - heel is OK, helping to keep the boom out and the sail full. Remember, heel means the board doesn't work as well, so the boat sideslips and does not point as high. But this is OK in really light winds, since forward speed is more important than pointing.

In strong winds, some heel is fine since it will help the boat get thru the waves easier, but try to get it flat in any smooth spots in the wave pattern.

Reaching, the boat sails best with the standard scow heel of 15 degrees, the rub rail just touching the water, except in planing conditions when the boat should be sailed flat and fast.

Downwind, the boat should be heeled the normal 15 degrees to leeward, but whenever there is enough wind to hold the boom out, then the boat should be heeled to windward. If the boat begins oscillating and control gets difficult, simply put down a little more centerboard. Oscillation can also be caused by having the vang too lose, so look up and check to see that the leach of the sail is not too 'open' or curved.

Remember, the most important component on any boat is the sailor. Skill and experience has made it possible for many boats to win championships, but never has a fast boat made it possible for an unskilled sailor to win. Good luck, and have fun.

©Jim Young All Rights Reserved