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Home , Apparent wind, Death roll, Sailing, Sailing (sport), Sonar (keelboat)

IN SEARCH OF SPEED 2nd edition A collection of “Go Fast” theory By Peter Galloway

I get a lot of questions about speed or, more accurately, how to obtain it. Questions that range from shape and trim, minimum weight to rig tune to shape, shape, crew weight, etc. It seems to touch on about everything that might affect how fast a boat gets around the . I’ve undoubtedly postulated on all of these specifics over the years, but never compiled a brief dissertation on all of them at one time. This is an attempt to do just that. These are merely personal observations or theory, and may not be subscribed to by all knowledgeable racing . They are the product of years of trying different things, analyzing the results, and coming to some sort of conclusion. Some of them, I am not even entirely sure are correct! After all, I’ve known a number of talented sailors who seem to be ignorant of, or merely do not worry about the details, but have enough natural talent to win anyway. I’ve seen times when what is ordinarily a mediocre boat is instead wickedly fast in certain conditions. An explanation might be that any given combination of keel shape, hull preparation, crew weight, sail shape, trim and steering happens to be ideal for that set of conditions and that same boat might demonstrate its mediocrity when faced with a different set of conditions. Before I begin, consider that maximizing a boat’s speed through the water is only one ingredient necessary for winning. Strategy, tactics, execution, crew work, observation, a keen mind, mastering the conditions, etc. are but a few of the other ingredients needed to be successful. These don’t come from spending an inordinate time on your keel or or polishing your bottom. They come from skill and experience and practice and these are things you cannot find in print. But when combined with a well prepared boat, all of these contribute to a winning advantage. I dare you to name an Olympic who has not agonized over his or her equipment. You just don’t leave stones unturned if you want to win at a top level of the sport.

Speed boiled down to the essentials Consider that the winning boat in any given race is the one with the greatest average speed around the course. You can achieve the greatest average speed in one of three ways: 1. Be slow, but sail by far the shortest distance, i.e., start well, stay in the pressure and hit every shift perfectly. 2. Have superior speed through the water in enough abundance to make up for strategic or tactical mistakes. 3. Have a combination of both (A winning combination). This document will focus on the item two only.

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1. HULL It stands to reason that you would like to start with a good hull. By that, I mean that you sail a boat that is constructed by a leading, proven builder and that the hull is both stiff and fair. Ask around and/or research which builder is building the fastest . What are the consistent winners using? Look for construction methods and materials. Look for attention to detail. Look for shape and finish. Look for the best hardware and layout. And look for durability. If you are not buying new or are not having it constructed to your individual tastes, then look for a used boat with a good record. It’s no surprise that the fastest boats with the best records are worth more, many times because these boats have already been optimized saving you much pain and expense later on. The lesson here is to start with a proven piece of equipment. If you are having your boat built to order, try to stay away from unusual color combinations. An all white hull simply works best. White fades less when exposed to the sun, is easiest to cosmetically repair when damaged and looks great for years to come. It is also the stealthiest, especially if most of the other boats are all white. I remember a sailor I once knew who came from another class that sailed in fleets with a rainbow of hull colors. He ordered a custom boat with a bright red hull. Imagine his surprise when he showed up for his first big regatta to discover that the rest of the fleet was all white! He stuck out like a sore thumb and had to refrain from being aggressive on the starting line for fear of being noticed too easily. As for the deck, consider an off white color such as light gray or beige. These colors reduce the reflection on bright days and as such are easier on the retinas.

2. BLADES There is not a subject that elicits more opinion than the shape of blades. By blades, I mean , centerboards and . Being a sailor most of my life, my observations are based on that type of boat, so I will not delve into the theory of centerboards here though much of it may be applicable. Keel We all recognize that you cannot change the overall design of a keel in a one design class. But all things are made to a tolerance, and boats typically have a fairly loose tolerance to account for the hand made nature of the construction. Within any given set of tolerances there may exist fat keels, skinny keels, long keels, short keels, deep and shallow keels. Keels with their location of the greatest chord thickness varying fore and aft, and differing leading edge radii and varying keel location. With so much to take into consideration, what works the best? The answer is…nothing all of the time. Optimum keel shape is very much a function of the conditions and the angle. Clearly very thin keels exhibit the least at zero as would be the case while running (no leeway). But thin keels may also provide less at some given angle of attack (as in sailing upwind) resulting in more leeway. Generally a thin keel would be superior in flat water conditions or when sailing downwind and it would be inferior in breezier or choppy upwind conditions because a thin keel loses its lift more readily than a fat one.

Page 2 of 16 Which would I choose? I would choose a compromise that is good in most conditions and sailing angles. A lot to do with my choice would have to do with the conditions I generally sail in. If I mostly sail on a lakes with primarily flat water, I might choose a thinner shape. On an ocean with rough water or a typically breezier location, I would opt for a fetter keel. More lift is more valuable than less drag most of the time. Consider that a boat a greater distance on upwind legs than downwind legs, and that assumes an equal number of upwind and downwind legs. Factor in that many courses have an additional upwind leg, and you can see that 75 % of distance sailed might be upwind. Also, I would rather be faster upwind so that I can get to the first with the leaders and not have to play catch up the rest of the race. But additional lift can be achieved without the expense of additional drag. Additional lift can be achieved by a deeper keel while reduced drag can be obtained by having a keel with minimum chord length. All of these are compromises for the sake of good all around performance in a wide variety of conditions and sailing angles. Here is my opinion on the optimum all around keel: • Maximum depth (additional lift) • Minimum chord length (reduced wetted surface) • Section widths closer to the minimum (minimum drag) • Median leading edge radius (better at high angles of attack or chop) • Minimum trailing edge thickness or radius (minimum drag) • Maximum thickness approximately 40% aft of the leading edge (greatest lift to drag ratio) • Max aft position (better balance) And don’t forget symmetry. The lift characteristics of an asymmetric keel vary on each side resulting in differing performance on opposite . Simply stated, an asymmetric keel is just plain slow. Much of the same applies to rudders. Interestingly, a rudder produces a higher percentage of the total lift than one might believe. That is because windward helm actually provides additional lift. But too much helm comes at the expense of drag. So here are my criteria for rudders: • Minimum depth (for least drag) • Minimum chord length (reduced wetted surface) • Minimum section width (least drag) • Minimum trailing edges (least drag) • Median leading edge radius (good lift an higher angles of attack) • Minimum weight (less pitching moment)

3. FAIRING A “fair” hull promotes laminar flow and reduces turbulence. So what do I mean by fair? A fair hull is one that is devoid of major and minor undulations to the surface. That is, the surface flows in a continuous curve with no high spots (bumps) or low spots (hollows). As the water rushes past your hull, it accelerates as the hull grows in width, and then begins to decelerate as the hull narrows. If it encounters bumps or hollows, this natural acceleration is interrupted and results in the initiation of turbulence. Any aerodynamicist

Page 3 of 16 will tell you that all flow over a surface eventually becomes turbulent, but the trick is to maintain the laminar flow for as long as possible. More laminar flow equals less drag and vice versa. This may be an over simplification of the theory, but the general principle is correct. Thus, a completely fair hull should be the fastest hull. So okay, how do you get a fair hull? Well, by sanding the surface with a very long board in the fore and aft direction. Also called “long boarding”, this sanding technique is designed to eliminate the high and low spots resulting in the perfect hull. However, there may be bumps and hollows that are too great to sand away without breaking through the gel coat to the fiberglass below. Most class rules prohibit this sort of excessive sanding, but some allow minor filling of hollows by using a “high build” epoxy primer. If allowed, this can be an effective way (combined with a lot of elbow grease) to achieve a perfectly fair bottom but it adds weight. As for me, I just sand as much as I can and skip the primer.

4. SURFACE FINISH Smooth, smooth, smooth—need I say more? How smooth is smooth? Some will argue that sanding with anything finer than 600 grit is a waste of time. I don’t. In fact I go all the way to 2000 grit. A thorough sanding with 2000 produces a shiny finish that does not require buffing. I would prefer to start with an long (about 24-30 inch or 600 to 750mm) by 3-4 inch wide board that is sufficiently flexible to bend lengthwise (See FAIRING above). Then use two or more sheets of 320 grit wet sandpaper and sand with long fore and aft strokes to fair out the high spots. (Be careful not to sand through the gel coat). Then switch to a hard flat board about 12 inch or 300mm long that you can grip one complete with, and continue with for and aft strokes using successively 400, 600, 1200 and 2000 grit until all of the sanding scratches are eliminated. Since this will take considerable time to do properly, use a few drops of dishwashing soap in the water to wet the surface better and replace the sandpaper frequently. It is false economy to be frugal with the paper, as its cutting ability is greatly reduced after a few dozen strokes. The job will go a lot faster if you change the paper frequently. I for the auto body supply store and buy packages of at least fifty sheets. Sand the entire hull up to the gunnels if possible and spend more time on the forward 1/3 of the hull as a smooth entry promotes laminar flow. Finally, be sure to fill all defects and smooth them. Defects cause turbulent flow.

5. COATINGS Wax No wax please. Wax resists wetting, and allows the natural surface tension in water to cause beading. It’s great for your car’s paint job, but not for your bottom where it is, in my opinion, slow. The water molecules directly in contact with your hull actually move with it. Molecules adjacent to these move slightly faster relative to the ones closer to the hull and those next to these move faster still until the water molecules are moving by the hull at your boat’s speed. This transition in the speed of the molecules is known as the Boundary Layer and is an important factor in reducing skin friction.

Page 4 of 16 In essence, water acts as a lubricant. The Egyptians used water to lubricate the skids while moving the enormous blocks used to construct the pyramids. Early wood machinery used water to keep the gears turning. We all wet our fingers to remove a tight ring. Ideally we want the water molecules to attach to the hull readily, not avoid it. -Brite and Hullkote However, it appears to be okay to use Teflon based polish (I recommend Star-Brite with Teflon). This polish does not seem to inhibit the wetting that a wax does and it has the added benefit of helping keep the hull clean. Recently I have discovered McLube HullKote. This pleasantly scented coating applies easily and does a fine job of protecting the hull. I like applying it over the Star-Brite. So if you are going to use Teflon polish, be sure to apply it thoroughly. I recommend three applications (put it on and take if off three times—the hotter the weather the better) to assure 100% coverage. If you use Hullkote, either two thorough coats of this or one coat over two coats of Star-Brite. Soap Soap is good for more than cleaning. Before a big regatta I like to soap the entire hull with clear Ivory dish soap and let it dry. It washes off pretty quickly, but helps keep oil and other nasty stuff from sticking to the hull when you launch. Bottom Paint If your class requires bottom paint or you simply have to use it, use a hard coating over a fair surface and be sure to sand it absolutely smooth. I have witnessed many a boat with properly applied and sanded bottom paint that are every bit competitive with bare hulls.

6. MINIMUM WEIGHT Everybody wants a boat that is minimum weight or just under. I’m no exception. Ideally, I would like a boat just a few kilos under so I can ballast to minimum weight. But if your boat is a few kilos over the minimum, don’t fret. It may actually help by adding stiffness to the hull and, if in the keel, righting moment. If it is more than 2% over minimum weight, it then starts to become a handicap. If you are over the minimum weight, first check for water. Are the buoyancy tanks leaking? Is the rudder absorbing water (a very common problem)? If there is no excess water, then consult the class rules on how you may legally reduce weight. Taking it out of the fiberglass is rarely legal and could actually have an opposite effect in reducing stiffness. Instead. Look to reduce fitting weight, line weight, etc. While on this subject, remember that if you are carrying a ton of excess gear or equipment, then you are just kidding yourself by fretting over a few pounds of excessive hull weight. The point I am trying to make here is to limit the gear you carry to the necessities.

Page 5 of 16 7. MAST Section If you have a choice of sections, first, see what the fast boats are using and consider using that make or section. You might also want to check with your sail maker and see if they can provide any recommendations. If your luff curve is designed to fit a particular make or mast section, then it is good to know what your sailmaker used for their design. Stiffness If I had to make a judgment, I would usually opt for a stiffer section as greater stiffness provides better control. For example, a soft section will tend to bend more as it is loaded, either fore and aft due to increased mainsail tension thereby over flattening the main, or side to side as the strength increases. The latter can cause the tip of the mast to fall off to leeward causing the main to over-flatten up high. Tip weight Whichever brand mast you may have, it should have minimum allowable tip weight. Excessive tip weight causes additional pitching moment as well as additional heel. There is no upside that I can think of for a heavy mast except stiffness. But you can have a stiff mast and minimum tip weight if you choose your mast fittings and carefully. To reduce weight, consider using the lightest possible fittings where you legally can and use lighter halyards.

8. RIGGING & DECK LAYOUT Over the years I have spent a great deal of time trying to optimize my boat’s rigging because a well rigged boat is easier to sail, and an easy to sail boat is usually fast. My goals are: simplicity, lightness, efficiency, ease of use, effectiveness, and necessity. I choose the blocks and fittings carefully, considering the size, weight, strength, design and suitability to the purpose. Then I choose placement in the boat making sure that lines are led as fair as possible with minimum of friction. I consider the mechanical advantage of and tackle systems taking into consideration the general strength of the crew, and it is imperative that adjustments are readily accessible and easy to use with minimum friction. Reliability Everybody experiences breakdowns and I’m no exception. Usually these occur at the worst possible moment and are hard to recover from. In the worst instance, they can take you out of contention in a regatta. So periodically spend some time looking over your fittings and rigging. Inspect for wear, chafe, corrosion, cracks, missing cotter pins, etc. Catch the failures before they prove costly. New ideas While you are at it, check the layouts on the hot boats for new ideas. But be sure to check with your class measurer on any new rigging ideas that may be in violation of your class rules.

9. SHEETS & HALYARDS I have a phobia against heavy lines. I prefer to use a size smaller where I can and I carefully choose the material to suit the application. Here are my preferences.

Page 6 of 16 I like to use a tapered line of low stretch Technora or Vectran with a polypropylene cover. Then I go further to remove the core for most of the cover leaving a core and cover for a length of about a meter in the area that the halyard is cleated. The polypropylene cover does not absorb water and when the jib is down, the coreless cover is up the mast, reducing weight aloft. Main halyard I’ve tried exotic ropes, but they invariaby stretch too much due to their woven construction. There is no substitute for 7x19 wire rope. But the tail of the halyard has only to be a minimum size line. Once the main is up, the tail serves no purpose and usually sits in the bilge where it can absorb water, so use a non-absorbing tail. And don’t forget to use a halyard lock where possible. halyard I use the same construction as the jib halyard except I use Spectra for the core, as it is the lightest of the super exotics. Stretch is not so much an issue with a spinnaker halyard. And save the weight aloft by forgoing the shackle. Topping lift If you are anal as I, you can taper this line also. If you do, use a Spectra core. Spinnaker sheets I like a continuous line to save weight. A continuous line can be 1/3 less in length than two individual lines, but you should have a capable crew as it can get to be dangerous if you have an instance of the sail getting behind the boat or going overboard. For construction I taper a Spectra core into a polypropylene cover and prefer to tie them to the spinnaker to save the weight of the brummel hooks. Mainsheet and jib sheets Here is one place I do not go to exotics preferring the feel of Dacron polyester. I like to use one size smaller than usual.

10. SAILS Shape More time is spent worrying about sail shape, and justifiably so. To use an automobile analogy, the sails are the engine of your boat and the shape is like engine displacement. Shape produces lift and thereby, power. More power equals more speed (not always, but more on that later). Sail shape is the aerodynamic form exposed to the wind. The lift off your sails produces forward thrust and heeling moment. Optimizing the shape to produce maximum forward thrust is what we strive to achieve. There is no exact sail shape that is ideal for all conditions. A deeper sail might provide more power and lift, but suffer from greater drag and the converse is true. In light you might need a shape to provide as much power as possible, while in heavy winds, more power will result in more heel, increased helm and leeway. Obviously a sail designer could create a shape that is optimized for a certain set of conditions. Sails designed for a region that is known for primarily light air would be different from sails designed to a region. The challenge to a sail designer is to produce a sail shape that is suited to the widest range of conditions.

Page 7 of 16 Fortunately a sail is flexible, and with the myriad of adjustments available, its shape can be changed to suit the conditions. A can be used to flatten a mainsail and open the leech. A or halyard is used to adjust the fore and aft position of the maximum depth. The adjusts the depth in the lower half of a mainsail. Location of the jib car adjusts the twist and angle of attack along the luff. Knowing what controls to use at what time and in what quantity is a matter of knowledge, skill and experience. There are generalizations that can be made about shape. For example, the point of greatest depth for a mainsail on a is approximately 45 -50% aft of the luff. For a jib, it is about 35-40% aft of the luff. On boats, the mainsail above the hounds does not have the jib as a header, thus the above that point should be somewhat further forward. Trim Sail trim is the process by which you change the shape of a sail and how its shape is presented to the . It is also possibly one of the least understood aspects of the racing. There are a lot of different ideas as to what trim is fast, but none of them is applicable for all conditions or circumstances. There is a different trim for heavy air versus light air. There is a different trim for when you want to point versus foot. I’ll delve into the fundamentals without going into great detail in this article, so much has been written by so many far more expert than I. Mainsail We’ve all heard that a good starting point for trimming the main is the tension the sheet until the top batten is parallel to the . This can be difficult to judge from the rail so the absolutely best method is the perch below the center of the boom and sight up. You might be surprised as to how easy it is to close the leech inadvertently. Upwind, the best location for the traveler (assuming you are not overpowered) is such that when the top batten is parallel, the boom is on centerline or slightly above. When you achieve this condition in a moderate breeze, be sure to mark the mainsheet so you can duplicate it without having to constantly sight under the boom.

Jib Apart from the sheet tension, the fore and aft location of the jib car is the most critical. Moving the car forward results in a deeper jib down low and closes the leech, thereby increasing the angle of attack up high. In conditions where I am after max power, I adjust the car position and sheet tension so that the sail stalls simultaneously along its luff while allowing the upper leech telltale to flow 80% of the time. In conditions where you need to de-power, bring the cars aft. This will open the upper leech causing the upper half of the sail to flatten and de-power. You can move the cars a lot more than you think, especially when it is very windy. I might move it 4 inches or more back when it is blowing hard. This way when you trim the jib until the bottom is flat, the top is open, spilling power and complementing a twisted mainsail. In extremely windy conditions you may even have to ease the jib slightly. If your main is back-winding badly in a fresh breeze, is usually means the jib car has to move aft and/or the jib eased slightly.

Page 8 of 16 Slot effect The slot is the opening between the leech of the jib and the luff of the main. The apparent wind is funneled through the slot and that causes it to accelerate since it is being forced through a smaller opening. Bernoulli’s Principle states that a medium flowing at a higher speed does so at lower pressure. This lower pressure accentuates the lift generated by the mainsail. That is why a jib is so beneficial to a sailplan and adds much more power than its sail area alone. Dropping the main traveler affects the slot as does twist in the sails. When you drop the traveler or twist the main by easing the sheet or by adding backstay, you close the slot. You also close the slot by trimming the jib. If the traveler is dropped significantly and nothing is done to adjust the jib trim, the main will backwind (see Jib above). There is an optimum slot for all conditions and I like to think in terms of controlling the slot by balancing the twist in both the main and jib. Spinnaker We’ve all heard the rule about keeping the foot of the sail parallel to the horizon. Good advice to be sure, but I like to think more in terms of keeping the center seam vertical. Adjust the pole height to keep it so. Keep the pole perpendicular to the apparent wind and ease the sheet so as to keep a small curl in the luff of the sail. So you say, “Big deal—we already know this stuff! What really great go fast tips do you have?” Here are a few tips on spinnaker flying: • In lighter winds I like to sail the minimum angle from dead downwind so as to cause the spinnaker to erect. Try this some time. Start by sailing dead downwind with the spinnaker hanging pretty much like a rag. Then slowly head up until the sail all of a sudden erects and takes it’s designed flying shape. This is the optimum sail angle. No lower and no higher. • Try to have the trimmer control both the sheet and together. That is, don’t the guy unless necessary. Consider that an ideally trimmed spinnaker presents and optimum shape to the apparent wind. When the helmsman heads down, the guy needs to be trimmed and the sheet eased simultaneously in order to maintain the same shape as seen by the apparent wind. The opposite is also true. This continual rotation of the spinnaker when changing course cannot be done with the guy constantly cleated. • As the wind increases, the fastest course is usually achieved while sailing dead downwind. Many times it is better to heel the boat to windward to both project more sail area and add some . • As the wind increases, windward heel and/or projecting the spinnaker may make the boat difficult to steer and can result in the dreaded “”. I can tell you from experience that death rolls are slow. But they are sure entertaining talk at the bar! Anyway, I like to reduce the chance of losing control by tightening the HARD. This causes the “flaps” to go down and reduces the tendency to roll to windward. It’s amazingly effective. • In conditions keep the center seam of the spinnaker centered on the headstay. On a dead run this means the pole may have to be let forward some. By keeping the spinnaker centered, its Center or Effort will align with centerline of the boat and you will have no trouble controlling the helm.

Page 9 of 16 • Also, when in heavy air and getting ready to , center up the spinnaker and have the spinnaker trimmer cleat both the sheet and guy for the jibe. Then he can divert his efforts to getting the main across while the skipper keeps both hands on the to control the boat. • In moderate breezes while sailing dead downwind, ease the spinnaker halyard about 14 inches. By doing so you project considerably more area and the speed difference is noticeable, especially in conditions.

11. POINTING Novice skippers complaining that they cannot point frequently ask me what to do. They typically attribute the problem to rig tune, and so are constantly trying to solve the problem by changing it. You can imagine their frustration when they may not see the results they hoped for. What they don’t understand is that pointing is a function of several things. I like to reduce it to just three: Steering, Velocity and Sail Trim. Interestingly, tune is not necessarily on the list. I have to assume that most boats have reasonably good tune and if so, then tune should not be a factor. First, let’s define “point”. Logically, one might define point as the angle between a boat’s centerline as if moves forward and the true wind direction. Actually, that is not quite true. Point is the angle between a boat’s course over the bottom and the true wind direction. What’s the different you ask? In a word: leeway. Leeway is the sideways motion (slip) a boat makes as it travels forward. The actual course over the bottom is the vector sum of these two velocities. Therefore “point” can be defined as the angle between the true wind direction and the vector sum of your heading and leeway. If two boats are traveling at the same velocity with the exact same heading, but one is making more leeway than the other, then that boat is not pointing as well. Steering Some might believe that if you steer a course closer to the wind, you will point higher. But if your sails are already trimmed in and all you do is head up, you will likely end up pinching and we all know what that does—you slow down. And slow is definitely not fast! So while steering is important, velocity is just as important and that leads me to the next item. Velocity When sailing an upwind course, the faster a boat goes through the water, the more lift is generated from its blades. More lift equals less leeway. Less leeway equals more point. (This is very much like the apparent wind angle that is the vector sum of the true wind angle and a boat’s forward velocity.) So in order to point, you need to be traveling through the water as fast as possible in addition to steering the optimum course. You’ve probably heard the phrase “Higher and Faster” used when describing one boat’s speed relative to another. More accurately, it should be “Faster = Higher” because faster produces higher point. By the way, that is the main reason why angles are larger in lower wind velocities. Your boat is traveling through the water more slowly and producing more leeway. Think about it.

Page 10 of 16 Sail Trim for pointing Here’s how to better understand the basics of sail trim. explains it best by using a wing analogy. Most of us are aware that when a plane takes off or lands, it puts its flaps down to increase lift. When it picks up speed, it wants to reduce drag since its speed provides more lift than it needs. So it lifts its flaps, making the wings flatter. On a , more lift equals more power and more point. On a sailboat, the flaps are analogous to the mainsail leech. To put the flaps down you trim the main which tightens the leech causing the sail to get deeper. Voila! More point. But the penalty is drag. When you close the leech you may point higher, but you will also go slower. So when you need to go fast, but not high, you open the leech by easing the main. Obviously, there is a balance that you try to achieve under most conditions, and the top batten parallel to the boom trim usually provides it. However, there may be times that you might want to sacrifice speed for point. For example, when a boat tacks safe leeward and threatens to backwind you, or when you are very close to laying the windward mark, but need to point higher for the last few boat lengths. These are instances where over- trimming the main will produce the extra point you need.

Sail trim in extreme conditions Flattening There are two times when you need to flatten sails: When you are over-powered or in drifting conditions. • Over-powered: To reduce power while sailing upwind, you can do several things: 1. Use the backstay to flatten the main, open the upper leech thereby spilling excess wind and tighten the headstay thereby flattening the jib. 2. Trim the cunningham to move the draft forward in the main (stronger winds cause the draft to move aft from ideal position, especially true with well used .) 3. Drop the traveler to reduce the angle of incident to the wind. 4. Pull the jib car aft and/or ease the jib to open the upper leech. 5. Doing one or all of these things will reduce the power in the sails and result in your achieving optimum speed or the conditions. • Drifting conditions: In takes energy to alter the path of wind molecules. When the wind is “bent” around the sails, energy is needed to do so. With sufficient breeze, the velocity of the molecules provides this energy and the molecules “attach” to the sail producing laminar flow around the leeward side. Laminar flow produces lift. But in drifting condition, there is insufficient energy in the molecules so it is harder for them to bend around the sails and produce lift. To help counter this do this: 6. Use the backstay to flatten the main and tighten the headstay thereby flattening the jib. 7. Raise the traveler and ease the main and jib sheets to help lift the leeches. 8. Barber-haul the jib outward or hold it out by hand and lift the leech. 9. Remove all extra weight from the boom such as a stowed to help ease the leech.

Page 11 of 16 Flatter sails make it easier for the molecules to “attach” to the sails, thereby producing lift and power.

12. VMG Now I’m going to shoot a hole in the entire pointing argument. Fundamentally point is not everything. What’s that? After all you just said about point? It’s true. In the absence of other nearby boats that may influence your course, what does matter is Velocity Made Good. VMG is defined as the speed and point that maximizes your vector velocity directly toward the true wind. One boat may not point as high as the other, but if it is moving faster, may generate better VMG. The boat with the better VMG is actually making better progress directly toward the wind, and getting upwind as fast is possible is the basic definition of upwind speed. Think about it.

13. TUNING Everybody agrees that a boat has to be tuned properly in order to realize its speed potential. The problem is finding the right tune for the conditions. In the two classes I primarily compete in ( and ), the tunes could not be more different. Mostly this is due to the difference on the rig design and, more precisely, the mast section. Take the Sonar, for example. It has a very tall mast that is stepped on the keel and it has a very soft section. Plus it is a true 3/4 rig, so it has a lot of unsupported section above the hounds. Combine that with the swept back rig, and you have a noodle to contend with. By contrast, a Soling has a very stiff section that is stepped on deck. It has much less unsupported section above the hounds. Plus the shrouds are attached to ball bearing cars that travel on angled tracks that can be moved fore and aft over a range on 14 inches or so providing a lot a control in a variety of conditions. It’s a whole different animal and requires a totally different method of tuning. Because of the noodle rig, the Sonar does not like a lot of tension. Quite the contrary, while sailing upwind in a breeze it is normal to have very slack leeward shrouds. (To someone used to sailing a Soling, this can be quite disconcerting.) The reason the leeward shrouds go slack is because of the flexy rig and swept back shrouds. As you trim the main in a breeze, the mainsheet tension causes the mast to bend and the backstay to go slack. When the mast bends the distance between the hounds and the chainplates gets shorter and the shrouds go slack as a result. Remember how you string a ? You bend the bow to make the drawstring go slack. Same thing. The Soling, on the other hand, has a mast section that is so stiff fore and aft, that the additional mainsheet tension does not cause the mast to bend on its own. Thus the shrouds stay firm. But it doesn’t really matter whether your rig is stiff or a noodle. What matters is the straightness of the mast, as well as other factors such as rake, pre-bend, and sag. All of these items have well established fast values for most classes and most of the prevalent sailmakers in a class will have a tuning sheet to help you. And despite the dissimilarities of design, there are a lot of fundamentals that apply to both of these classes as well as others.

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Rake The correct rake in a boat is a function of balance. The idea is to position the center of effort of the entire sailplan such that while sailing upwind in a moderate breeze, the helmsman feels some windward helm. A little bit of helm is a good thing as it adds lift and provides feel. Increasing rake will tend to add and vice-versa. Too much rake will produce a heavy helm and encourage stalling of the rudder. The amount of rake that is right for your boat might be different from another boat due to keel shape and position. A boat having a keel in the maximum aft range of tolerance would be able to handle more rake than one with a keel further forward. But a lot of rake works against you while sailing downwind. It causes the spinnaker to closer to the mainsail just when you would rather have it our there in cleaner air. and Star boats can rake their masts well forward downwind with great effect. So, like everything else, rake has to be a compromise. Shroud Tension Generally, I like to sail with the least amount of shroud tension possible. High rig tension just tends to load the rig excessively causing increased mast bend, jibstay tension, hull deflection and a host of other lesser evils. When I feel slow one of the first things I do is to take a few turns off my shrouds. Lower tension will be a function of how straight the mast is. I find it can be fast in light to moderate conditions to have some mast sag (3/4 to 1-1/2 inch) at the spreaders while sailing upwind. The reason this works is because a slight sag in the middle of the mast counters the tendency of the mast tip to fall off to leeward thereby powering up the top of the sail. It also closes the center of the slot causing the wind to be accelerated more. This may be beneficial in light to moderate breezes, but in strong winds, it may actually desirable to have some tip off to flatten the top of the mainsail, and in these instances less sag would be in order. To check sag, have someone sight up the front of the mast from deck level. Then tighten or loosen the lowers to achieve the correct sag. Mast Blocks Many keelboat classes use mast blocks and if so, they are there for more than just filling the hole in the partners. The amount of mast blocking behind the mast at the partners controls the pre-bend (the initial bend applied to the mast without backstay or mainsheet tension). Mast blocking typically affects this pre-bend in the lower half of the mast while backstay and mainsheet tension affect the upper two-thirds. So with the combination of all three you can change the bend of the mast over its entire length and therefore, the shape of the mainsail. Forcing more pre-bend flattens the forward part of the lower mainsail and changes its camber in the forward third. So when do I change the pre-bend to change the shape of the mast? Oddly enough, I rarely use it to change the shape of the main. The outhaul seems to have a greater affect on the depth of the lower main than does pre-bend, so I use it for other reasons: 1. I pre-bend to stabilize the mast and help keep it from pumping. 2. I pre-bend to control the amount of jibstay sag. Of these, jibstay sag is by far the most important. More pre-bend slackens the jibstay (less tension) causing the jib to become deeper with a rounder, more forgiving entry,

Page 13 of 16 making it more powerful and easier to steer because it stalls less readily. However, if you overdo the pre-bend, the shape of the jib will suffer as will your ability to point. As a rule of thumb, I like to see just enough sag so that when the jib is properly trimmed, it just bounces very slightly in a chop. One more observation on pre-bend: If you have a swept back rig (chainplates aft of the mast partners), increasing the pre-bend will increase shroud tension in both the uppers and lowers, so it may be necessary to adjust the shroud tension when you change the pre- bend.

14. CREW WEIGHT & HEEL Basic physics dictates that the heavier the load your sails have to pull around, the more power is needed to achieve a specific speed through the water. This is the principle reason why a minimum weight boat is desirable. But the sails also have to haul around the gear and the crew, so on the surface, a light crew seems ideal, and for almost all circumstances when sailing downwind, it is. But what about while sailing upwind? In breezy conditions more crew weight reduces heel, allowing the blades to work more effectively, resulting in less leeway. Additionally, reduced heel allows you to carry more power in the sails. More power equals more speed (not always, but more on that later). So if more crew weight equal more speed upwind but less downwind, which would I choose? In my opinion, it is better to have more crew weight to reduce heel (assuming I need it), than to worry about it downwind. There is more of an advantage to be fast upwind than down. Early in this dissertation, I mentioned that a race consists of greater distance sailed upwind than down, so it stands to reason that having an advantage upwind would overrule an advantage downwind. Okay, while we are on the subject of heel, let’s talk more physics. We all have heard the term Center of Effort (COE). What is it? Basically, if we could reduce all of the forces on a to a single force applied to a single point on the sail plan, that point would be its COE. It is an engineer’s way of simplifying the loading for purposes of calculation. In addition, the Center of Rotation (COR) is the point about which a boat will rotate, usually around the keel or centerboard. Multiply the horizontal component of force at the COE times the radius to the COR, and you create a turning force called a moment. The greater the moment, the more the boat wants to turn. When a boat heels, the distance between the COE and the COR is increased. Thus increasing the heel will result in increased moment. To keep the boat going in a straight line, this moment has to be counteracted by the rudder. The more moment, the more rudder is needed and at some point, the rudder’s angle of attack will cause the flow of water around the rudder to actually resulting in less counteracting force. We’ve all experienced this as the boat does a sudden wind check even though the skipper has the tiller under his Adam’s apple! The bottom line of all this physics gibberish is that a completely upright boat has so little turning moment, that very little rudder is needed to keep it on course. Less rudder equals less drag. Less rudder equal less turbulence. So less rudder equals more speed (you see, there really is a time when less is more). Enough physics. Have I lost you?

Page 14 of 16 15. HULL SPEED & PLANING You naval architects out there already know what hull speed is, but for the rest of the great unwashed, let me simplify the term by defining it as the limit to how fast a displacement boat can go through the water. Generally this is a factor of the shape of the boat as well as it’s length, and generally, the longer the waterline length, the higher the hull speed. So this implies that any given boat will achieve a maximum speed no matter how much power it applies. It’s like a governor on a car. All of the horsepower in the world cannot make it go faster. And so it is with boats. When a boat is sailing at it’s hull speed, any more power will cause it to become overpowered. This one instance where more power does NOT equal more speed, and in fact, can equal less speed. Too much power causes increased heel, more helm and possibly instability making it more susceptible to broaching. When a boat become overpowered, it should reduce power while maintaining maximum speed. You achieve this by reducing sail area and flattening or twisting the sails. The trick is to figure out when to reduce power. That comes from feel and experience. However, there is an instance when there is no practical limit to speed, and this is while a boat is planing. Skin friction and wave action do not limit speed under these circumstances, so you can appreciate the need to achieve a plane as quickly as possible. Also when planing, it is imperative to get the crew weight aft in the boat as more power high in the rig tends to bury the bow. To balance the boat, get the crew as far aft as is reasonable.

16. WIND RESISTANCE Now I’m really going too far. Wind resistance? You’re kidding—right? Nope. The America’s Cup Class boats fuss over this so much it’s scary. They spend so much time in a wind tunnel trying to reduce drag that it seems ludicrous. But there is a lesson here. The only time wind resistance helps you is while sailing downwind. But while sailing dead downwind the apparent wind velocity is so low, that it is for all practical purposes, negligible. However, while sailing upwind, the force of the apparent wind is working to slow you down. Just consider the aerodynamic clothing that downhill skiers and bikers wear. Maybe there is something to this wind resistance stuff after all! Now, I’m not advocating that we all go out and buy tights. But I am saying be mindful of resistance. So minimize baggy clothes and keep your crew low in the boat and out of the wind where possible. When on the rail, keep them stacked up like NASCAR stock cars to reduce resistance.

17. TRAILERS What the heck does your trailer have to do with speed? Good question. By paying attention for how well the boat is caressed and how well the surfaces are protected, you can save yourself a bunch of grief later. If you have a full hull cover, use it when trailering. If you don’t or cannot afford one, then consider making a deflector to keep dirt and errant rocks away from the keel. Attach it between the forward supports.

Page 15 of 16 Most trailers come with cheap plywood support pads covered with even cheaper carpeting. I replace these with rectangular pads made from nylon with a better quality covering. In fact I like to use a synthetic, non-absorbing type material touching the hull to minimize the chance of blistering. Soap your hull and let it dry before a long road trip. When you get there, the hull will be a lot easier to clean. Road grime, oil and bugs wash off easily. Consider trailer boxes to store your sails and gear. Soap, sponges, hoses, buckets, spare parts, etc. can live there. Better in the boxes than in your car. It sure is easier to go to regattas and find stuff later. And while at it, check you tires for wear, pressure and load rating. Make sure they are designed for trailer duty and have adequate capacity for the load. I like Goodyear Marathon tires. They seem to be very durable. And the most important advice about trailers; make sure you wheel bearings are kept serviced and that the brakes work. It is very embarrassing to have your boat pass you at 65 MPH on the highway.

Remember, sailboat racing is like any other sport—it takes preparation, skill and practice to excel. With the above thoughts, I hope the reader will better understand some of the mysteries of the sport and help to achieve their dreams

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