THOUGHTS ON THE CARE AND FEEDING OF GADFLY III
(Webmaster Note: This article first appeared in the NODS , September 1995. It is reprinted here by popular demand. The author is the former owner of the “Marion Sails” loft in California, and a former member of an America’s Cup Racing Team. He currently hails from Texas where he is working on a PhD in Astrophysics.)
By Howie Marion
There was a great deal of interest in the fine yacht Gadfly III (National #821) after the recent World Championships. This boat has been owned and sailed by John Makielski since 1982. As most of you know, they both have seen considerable success and rarely miss a regatta. Last summer however, she was showing the strain of years of hard campaigning without significant maintenance. So during the early spring, we set out to repair and rerig Gadfly with the goal of making her simple and easy to sail. There are so many variables in our sport that if you can exercise control over any of them you should absolutely take advantage of the opportunity. In other words: you can’t always predict a wind shift but you can wetsand your bottom.
Before we could begin work on tuning and boat speed, we had to have a platform that was consistent and repeatable. The area from the mast step to the chain plates and the centerboard trunk must be absolutely rigid under all sailing conditions. On Gadfly, the forward bulkhead was broken, the top of the centerboard case moved more than an inch to each side under hand pressure, and the chainplates moved up and down about half an inch. The deck area around the mast step was also compressed a full inch.
The first thing we did was to rebuild the mast support between the deck and the hull. There are many good solutions to this problem. We used 2 columns of 2 inch PVC tubing which were installed with a fiberglass pad underneath and an aluminum channel at the top.
Next, we fastened this support to the front of the centerboard trunk and to the bulkhead with glass and resin. We were careful to establish load paths which extended all the way to the chainplate anchors. The bulkhead was reinforced and securely attached to the centerboard trunk. The two parts of the center board trunk were filled with cloth and resin, and bonded together. (This problem is unique to this hull and cockpit mold, If you don’t have one of the newer boats, you can ignore the last sentence.) The chainplate anchors were reinforced and bonded to the rest of the boat. All of this work was done with heavy glass cloth and epoxy resin. It’s not pretty or light, but it is strong. I estimate that we added 25 pounds to the hull. Polyester resin would have been fine except that epoxy had been used to install those plywood boxes that Gadfly used to sport. Remember: epoxy resin will stick to epoxy or polyester, but polyester resin will only stick to polyester.
Once Gadfly was again a solid piece of fiberglass, we improved her cosmetics by painting the cockpit area and installing a wooden cap on the centerboard trunk. The cap also serves to support a console for the control lines led aft.
We’ll begin our examination of the rigging at the top and work our way down. All mast dimensions on Gadfly, including mast band location and jib stay location, are within one half inch of maximum height. For 95% of the sailing done in National One Designs, it makes good sense to elevate your sail plan to the maximum height allowed by the rules.
The mast rake is 25 feet, 6 inches. We measured this by raising the jib and setting the jib halyard tension as we would for sailing in medium conditions. Then we tightened the back stay to just remove the slack without bending the mast. The tape-measure was attached to the main halyard shackle and the halyard was hoisted to it’s normal sailing position. This is not to the sheave on most Nationals but should be even with the top mast band. The measurement is taken from the halyard shackle to the corner of the deck and the aft transom, at the centerline of the boat. This number is intended to get you “in the ballpark.” It should be noted that there is quite a variety of deck shapes at the mast step and at the transom in the National Class. For each individual boat however, the mast rake number is relevant as long as the measurement is taken the same way each time. Mast rake information can be used to adjust your jib halyard settings when you use jibs with different wire lengths, and to verify tuning procedures from time to time.
We pinned Gadfly’s spreaders to prevent them from swinging. With no mast bend, the spreader tips are directly in line with the shroud path from the mast to the chainplate. (You can check this with your trapeze wires.) Fixed spreaders hold their tips further forward and out compared to spreaders which swing aft as the mast bends. The mast remains straighter on both axes and is much easier to control. There is also less headstay sag. The NODRA rules have some ambiguity about the maximum spreader length. It appears to read that the lengths are recommended and not mandatory. I suggest using spreaders that are at least 18 inches long.
The mast is a Proctor Gamma section. I don’t think the section specs are nearly as important as the fact that your sailmaker should know the bending characteristics of your mast on your boat. I saw a few mainsails at Leland which were new sails based on an older design. That design was probably fast when the National used heavy masts without much bend, but the sails did not look good on modern masts with aft-swept or swinging spreaders.
John has acquired many sails for Gadfly over the years and I have inspected all of them. My favorites are the Fisher sails designed by former World Champion Rob Frechette and built in 1989. These are the sails used by Sara & Joan at Leland. The Main is an excellent fit for the current rig configuration, and the Jib seems to be versatile through a range of conditions. Greg Fisher Sails is now a North Sails loft. Mark Makielski is the class contact.
Gadfly is rigged for vang sheeting. This style of sheeting uses the boom vang to control the leech tension on the main, while the mainsheeting moves the boom laterally. Many Nationals are rigged to use the mainsheet for leech tension and the traveller for lateral movement. Both systems work well. The mainsheet is split on Gadfly, forming a bridle at the end of the boom. The mainsheet cleat is on the back of the centerboard trunk. I prefer this to the “headknocker” cleat on the boom because you can trim easily in light air without jerking the boom around. The vang is a cascading 8:1 purchase which leads to a hole in the deck behind the mast step. It is easy to rig since the vang is never disconnected for travel. The tail is led to the console on top of the centerboard trunk where it can be reached by either crew member.
The backstay is led to the helmsman’s forward hand since most people steer with their aft hand. Don’t forget that the helmsman’s proper position is well forward in a National. (Notice the photo accompanying this article). The backstay can be an easy way to depower in puffy conditions. If it is rigged to make it convenient to use while hiking, a quick tug on the backstay control line will bend the mast, flatten the mainsail and open the leech. As soon as the puff passes, the backstay can be released which restores your normal mainsail trim. Sara is very good at this technique.
The forestay and jib halyard are led to the deck near to the mast step. The jib halyard is on an 8:1 magic box which allows adjustment while sailing. The halyard tension is increased about an inch in heavy air from the nominal medium setting. In light air, it is eased about an inch. The forestay is always slack upwind. Downwind however, the forestay is pulled tight in order to pull the mast forward and allow the jib to fly further to weather. Joan works this technique very effectively. In some conditions, this trim enables Gadfly to sail at greater apparent wind angles without losing boat speed.
The intersection of the forestay and the deck on Gadfly is 14 and 1/8 inches, and the center of the mast is 83 and ¾ inches from the forward measurement point. The chainplates for the shrouds are 94 inches from the measurement point and the lowers are 3/4 of an inch further aft. The fore and aft locations of Gadfly’s chainplates are determined by the internal structure of the boat. The shroud base is 48¼ inches wide, or 24 and 1/8 inches off centerline. This is very close to the class minimum which allows the jib to be sheeted as closely as possible without distorting the foot or the leech of the sail against the shrouds. Both the upper and lower shroud tensions are increased 2 or 3 full turns of the turnbuckles in heavy air, and eased 2 or 3 turns in light air. This adjustment is only done at the dock, and in practice is rarely changed from a light-to-medium wind position. The jib halyard control will also change rig tension and is much easier to adjust while sailing.
The jib leads are fixed at 9 feet and 1 inch from the intersection of the forestay and the deck. They are 3 feet 4 inches apart (or 20 inches off centerline) for a sheeting angle of 10.6 degrees. Because Gadfly has narrow side decks this appears to be a much tighter sheeting angle than found on some other boats, when in fact it is not so extreme. Since the mast rake changes very little, we decided to eliminate all fore and aft adjustment of the jib leads. There is no track to sit on and no arguments over lead position. If you want to open the jib’s upper leech, let out the sheet a couple of inches. Gadfly has never had barber-haulers and we saw no reason to install them now.
The jib sheets are led forward to the front deck for cleating. This permits the crew to roll tack effectively and still pull in the jib without severe contortions. Boats with wider side decks may not have this problem. We also use 1/4 inch jib sheets. These sheets run more freely than fatter line which makes the jib much easier to tack in light air. Every Gadfly crew member since this change was implemented has started out complaining about the small sheets and ended up complaining when they had to return to larger sheets in another boat.
The centerboard has a 5:1 uphaul and a 2:1 downhaul. The downhaul is necessary due to the weeds on Gadfly’s home waters of Eagle Lake. The board must be raised and lowered often to clear the salad from it’s leading edge. A 2:1 purchase is necessary because the board is bent slightly and jams in the trunk when it is raised most of the way. Both control lines lead to the console and are easily reached by either crew member.
Finally, we spent a great deal of time working on our underwater surfaces. Gadfly’s centerboard and rudder are Rich Ogrentz specials. They are 3/8 inch thick aluminum which is light and stiff, but the edges had only been rounded off. That was a big handicap in light air sailing compared to the thinner blades on many boats. We faired the edges of both the centerboard and rudder to the inch and one half maximum width permitted by class rules. The shape of the fairing is a knife edge rather than an airfoil shape. I believe that the work on the blades resulted in the single biggest performance gain Gadfly experienced.
The bottom of the boat from the waterline down, was sanded with 120, 220, and 400 grit wet and dry paper. I don’t believe that 600 paper adds anything. The blades received the same treatment
There were many other minor tasks such as filling little holes and adjusting hiking straps, etc. When you are sitting on the trailer, it’s hard to anticipate exactly how systems will function under sailing conditions. If you do much rigging work, you can expect to have to move a few things after sea trials. But by August we had achieved our goal. Since Sara and Joan had confidence that their equipment was well prepared and easy to use, they were able to concentrate on sailing. They certainly did that well at Leland!