Preparation from Dave Dellenbaugh's Speed & Smarts
Preparation involves more than simply your boat, however. In order to go fast, you have to be ready in every way possible, including your sails and crew.
The main point to remember is that what you do (or don't do) before you go sailing can have as much impact on boatspeed as what you do while sailing. You can't just jump on your boat, leave the dock and expect to reach your performance potential. If you aren't prepared, chances are good you'll return to the dock feeling like you wasted your time.
Unfortunately, finding and keeping good crewmembers can be difficult. The most important crew quality is undoubtedly enthusiasm. A novice sailor with energy and interest has much more potential in the long run than an experienced sailor who is burned out. An eager beaver will be much more willing to practice, make a season's commitment and work as part of a team.
Once you have a crew, you really need to spend time on the water. "Practice doesn't make perfect," said Vince Lombardi, "perfect practice makes perfect." When you go out practicing, always set a goal. Racing sailors are competitive by nature, and most will learn more from practice if it involves competition.
Practice tips:
Their general assignments for the standard positions of the crew are as follows:
Helm -- Primary responsibility is to steer the boat fast. Gives commands to help coordinate maneuvers. Continuously tells trimmers about feel of boat. Helps with tactics.
Cockpit #1 -- Mainsheet. Handles mainsheet, traveler and hydraulics. Usually doubles as navigator and/or tactician.
Cockpit #2 -- Trimmer. Responsible for trimming sheets and adjusting lead positions. Must keep track of boatspeed and target boatspeed. Talk with helm about steering and trim.
Cockpit #3 -- Grinder. Grind the winches and help with tailing of sheets and guys.
Pitman -- Tails and releases halyards. Handles topping lift, foreguy and other controls led to aft end of cabin house.
Mastman -- Handles all mast functions, including inboard end of pole, jumping halyards, reefing, etc. Helps foredeck gather and pack sails.
Foredeck -- Handles all foredeck responsibilities: sail changes, pre-start lookout, foot skirting, spinnaker set-up, etc.
Sailboats are fastest when their weight is concentrated in the middle of the boat. The higher the pitching moment (the more weight there is in the ends), the more the boat tends to bury in one wave and lift high over the next, pitchpoling and slowing itself down. Pitching moment also applies to weight in the mast; more weight here means, among other things, more heel.
When you understand how pitching moment is calculated, it's easy to turn into a fanatic about getting rid of weight in the bow, stern or at the top of the mast. Look at the formula for pitching moment:
Pitching moment = lbs. x ft^2
Let's say, for example, that you have a 20 lb. masthead fitting on the top of your mast. This fitting is 40 feet away from the boat's center of gyration. Therefore the fitting contributes 20 x (40x40) = 32,000 foot-pounds. For every pound you can remove from that masthead, you will reduce the pitching moment by 1,600 foot-pounds!
The big contributors to a boat's pitching moment are the following:
Safety Equipment -- The crew's safety is an often-overlooked and obviously very important part of preparing your boat. Not only should you ensure that you have all the safety equipment required for your racing category, but everyone onboard should know where the equipment is and how to use it. In an obvious place down below, post a waterproof page with a list of all the equipment and where it is stowed.
Items like life jackets, safety harnesses, lights and flares should be easily accessible. If it takes five minutes to dig out your life raft, you may as well not carry it. Every time you have someone new onboard, review safety procedures, especially man overboard. Whenever you have a chance, throw a life cushion overboard suddenly and make the crew pick it up as if it were a person in cold water.
Don't forget the seasick pills and other first aid supplies. You'll be surprised at how many people get seasick offshore. To go fast, you definitely need all crewmembers functioning as well as possible, and this can be a significant part of preparation.
Weight -- The mast is a notorious contributor to pitching moment; excess weight here is slow. Besides reducing all-up weight, keep the mast's center of gravity as low as possible. With an older boat, consider the purchase of a modern racing mast.
Windage -- Windage creates drag by interfering with the air flow just as it strikes the leading edge of the mainsail. A well-designed mast minimizes the area projected to the closehauled apparent wind.
When the diameter of a mast is reduced, the thickness of its walls must be increased to preserve its overall strength. A small-section, thick-wall spar can be safely bent further than a large-section, thin-wall spar of equal strength. So the small-section spar not only has less drag, it allows more control over the mainsail.
Triple spreader rigs are often used on bigger boats to reduce weight. The spreader tips act as anchors for the bend-inhibiting upper shrouds. The combination of a triple spreader mast and highly tensioned shrouds produces a spar of considerable strength and rigidity. However, such a mast is vulnerable to focused loads such as a spinnaker pole rolling into the water on a broach.
The efficiency of underwater foils depends on their shape and their fairness. With a J/24, for example, a factory-fresh boat is not competitive until the keel has been faired. Here are some ideas for how to get the most out of your "blades."
Shaping your foils -- Ideally, your keel shape should conform to the 4-digit series of NACA foil sections in Abbott and Von Doenhoff, Theory of Wing Sections (New York, 1949). To make a set of templates for your keel, follow this procedure:
Use a given template for chord lengths equal to or shorter than itself. Snug the leading edge of a too-long template into position, letting the last few percent of the template hang off the trailing edge.
Fill in the hollows with epoxy and then sand, sand, and sand some more. Consult an auto-body instruction manual for the best tips on shaping and sanding; the topic is too lengthy to be included here. Some tips:
Sand in a crisscrossing pattern of diagonals, using plenty of water to wash away the grit. Two drops of detergent per bucket of water help to prevent the paper from clogging. Change your water and replace your paper frequently -- the job is tedious enough with clean water and sharp paper.
Sand with 220 only until you have taken the gloss off the paint and achieved a uniformly matte finish. Check your work by squeegeeing the excess water off the hull and viewing it against reflected light. Once the 220 work is completed, switch to 400, sanding in the direction of the water flow (at 45 degrees to your 220 strokes). Stop sanding as soon as the 220 scratches disappear.
The surface is now covered with 400-grit scratches, which are basically "invisible" to water. Further sanding, buffing and polishing will not reduce skin friction much, but will improve the longevity of some paints by reducing the surface area exposed to corrosion. Be sure to wipe away the grit with a sponge before it dries, lest it cake on and require resanding.
Laminar attached flow -- Laminar flow involves smooth layers of fluid streaming over the sail or keel with virtually no mixing between layers. A marble sinking into a pot of maple syrup experiences exceptionally "clean" laminar flow.
Under the right circumstances, laminar flow can develop phenomenal lift-to-drag ratios. However, it is easily disturbed, hard to re-establish, and only occurs on perfectly fair (no dumps or hollows) and smooth (no gritty roughness) surfaces. It occurs more readily at slow speeds, on the leading edge of foils, or in viscous (thick) fluids. Only a very small part of the flow over any keel or sail will be laminar, and that will happen only part of the time.
Turbulent Attached Flow -- Turbulent flow is a more forgiving type of attached flow. Normally, laminar flow over the leading edge of a foil changes into turbulent flow for the middle and trailing sections.
The transition from laminar to turbulent is easy to simulate. Simply turn on a (non-aerated) faucet slightly so that a thin stream of water pours out. This is laminar flow. Now, turn up the faucet gradually. Eventually it will turbulate, breaking into a strong, bubbling stream. Increasing the velocity of the stream creates turbulent flow.
The goal when finishing your bottom and trimming your sails is to establish attached flow. The laminar-turbulent distinction, while fun to speculate about, bears no practical significance for racing sailors. Laminar flow's sensitivity to disturbance makes it a rare and fleeting phenomenon on the sails or keel of a boat crashing through the waves.
Separated flow -- Here is the real villain. Whenever you have rough spots on your keel, an overtrimmed sail or turn your rudder abruptly, your sail, rudder or keel will stall. On a stalled foil, flow has separated from the surface and refuses to follow its curve.
Separation starts at the trailing edge and progresses forward. Partial separation is neither bad nor uncommon; typically, 10%-20% of your your sail has separated flow when you sail upwind in medium air. But when the separation point creeps up to the leading edge of your genoa and the leeward telltale begins to dance, the lifting force plummets abruptly. The same thing happens with your keel.
Sometimes, of course, stall is the best you can hope for. When sailing on a run, for example, your mainsail is working under 100% stall.
The golf ball -- The classic example of laminar, turbulent and separated flows is the golf ball, which has certain similar characteristics to your bottom and keel. Golf ball dimples are designed to lower drag and increase range. Here is how.
A perfectly smooth golf ball develops laminar flow along its leading edge. Air flowing over the forward half of the ball reamins attached and laminar. But once it rounds the corner and attemps to follow the surface's curve back in, the air runs into trouble. Since laminar flow is by nature easily destroyed, it separates from the golf ball almost immediately. The separation point is just behind the widest section of the ball, so the ball drags a wake of eddies as wide as itself through the air.
The early golfers noticed that their old, chewed-up balls flew farther than brand new, smooth ones. Evidently, the roughness turbulated flow and reduced, not increased, drag. Turbulent flow remained attached to the golf ball longer, separating into eddies only after its diameter had narrowed considerably. Golf balls now come from the factory with the right amount of roughness (dimples) built in.
There implication of this for boats is that your bottom doesn't have to be perfectly smooth. In fact, a bit of roughness may actually help. The famous "riblets" on Stars & Stripes' bottom are a great example of a non-smooth surface that maintains laminar flow longer and thereby reduces drag.
Boatspeed -- The location of the sensor is critical. It should be located close to the centerline of the boat. More important however, is the fore-and-aft placement. If the sensor is too close to the keel, increased lateral flow of water when the boat is heeled over changes the sensor's readings. If the sensor is too far forward, it is affected by wave action, and may even come out of the water when the boat goes over waves. These obviously will produce erroneous results.
If the boatspeed sensor is put back in the boat differently after the boat has been out of the water, the sensor will read different values. The alignment and depth of the sensor should be marked to duplicate the previous installation. This is important for consistency in results.
Apparent wind -- The sensor for apparent wind at the top of your mast is affected by many factors: upwash from the sails, leeway, heel, and symmetry of the wind vanes, mounting bracket and masthead crane. Obviously, if the vanes are bent or the mounting bracket is loose, there will be inconsistencies in your readout.
Having an out-of-line backstay crane has a subtle but even more dramatic consequence. As backstay tension increases, the top of the mast twists, along with the masthead unit. Wind angle readings will be different on each tack. Another thing to watch out for is bent anemometer cups, which will reduce your apparent wind velocity readings.
Genoa lead angle -- Knowing this angle will be important when we get into genoa trimming. Figure 21 shows a method of constructing a small triangle on the foredeck and then extending its hypotenuse aft to arrive at the lead angle for an existing (or future) genoa track.
Rudder angle -- The angle that your rudder makes with the centerline of the boat is your best measure of windward helm. When your boat is out of the water, mark your helm at the 0 degree, 2 degrees, 4 degrees and 6 degrees positions to port and starboard. Use tape bands on a wheel or scribed lines on the deck or rudder post for a tiller. To find the calibration points, follow this procedure:
Spreader references -- Put bands of tape (reflective tape is best if you sail at night) around your upper spreaders at 3 inches, 6 inches and 12 inches in from the spreader tip. These bands will serve as a stationary reference point to help judge how close the genoa is trimmed to the spreader.
Halyard tension -- Mark your genoa halyard at maximum hoist so you won't raise the halyard too high, and so you'll have a halyard tension reference. Mark the halyard so your mark is at the black band when it is two-blocked. Place a scale on the mast alongside the genoa halyard with the zero point at max hoist. If you have wing halyards, mark them where their shackle is even with your centerline halyard. This way you can use the same genoa halyard numbers with any halyard.
Sail preparation begins at the end of your last race. Make sure that you rinse off salty sails with fresh water and dry them before folding. The last thing you want is to reach the starting line and realize that your 3/4-ounce chute is still wet from that overnight race three weeks ago.
Genoa care -- It's absolutely essential that you put spreader patches on every genoa before you go sailing with it. A genoa without spreader patches is an accident waiting to happen. One other caution about genoas: Do not exceed the sailmaker's recommended wind maximum. If you do, you'll either have a balloon or shreds.
Label the sail bags and clews -- Make sure all your sail bags are marked clear enough on the outside so a bleary-eyed mastman can find them when doing a sail change at 2 in the morning. On the clew of every sail should be written the following: Sail ID, maximum wind for sail, lead position. You can also add other numbers such as halyard tension and distance off spreader.
Pack and flake sails -- Before you get to the race area, be sure that all your headsails and spinnakers are packed neatly in their bags, ready to be used at any moment. All sails should have head, clew and tack readily accessible. Heavy-air spinnakers should be stopped with rubber bands or yarn.
Telltale placement -- Put telltales in the following places -- front of jib (about a foot back from the luff); leech of main (usually on the batten ends); and on the shrouds, backstay, topping lift, etc. Yarn is the best and attaches to sails well with sticky back tape. For jib telltales, use red on port and green on starboard, with one side always higher than the other. This makes it easier for the helmsman to figure out which telltale is on which side.
Regularly inspect all the standing and running rigging, steering gear, sails, fittings and electronics before every race that you intend to win. Tape every exposed sharp edge and cotterpin. Stock your onboard tool kit with the following items (lightly coated with oil to prevent rust):