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BOATSPEED , AND TACTICS

Taking the Guesswork Out of Tactics

Twenty-five years ago a tactician might have been aided by an analog stopwatch, a bulky hand-bearing compass, and Loran C. Today, on-deck computers and sophisticated software programs have completely revolutionized the role of the modern tactician. Educated guesswork is no longer good enough to get the job done. Knowing precisely the time and distance to a mark, or exactly how favored one end of the starting line is, allows the tactician to do his or her job better. Making informed

THE START SCREEN is the modern way for a tactician or navigator to determine which end of the line is favored and relay critical time and distance numbers to the helmsman.

decisions and communicating them to the helmsman, trimmers, and bow team make the mechanics flow smoothly.

For this, on-deck screens are invaluable, but they have to be used properly. A tactician still needs to spend as much time as possible with his head out of the boat, so learning and setting up the programs before the race is critical.

There's almost too much data for any one person to comprehend in any of the tactical programs, so it's important to set

THE START SCREEN is the modern way for a tactician or navigator to determine which end of the line is favored and relay critical time and distance numbers to the helmsman.

up the various screens in a logical order. I prefer to see heading, boat-speed, true wind direction, true wind speed, and true wind angle on the left side. I then put current set and drift, depth, course over ground, and speed over ground in the center. Tactical functions are on the right: time to layline, time to waypoint, distance to waypoint, and

THE STRIP CHART page is the perfect way to track trends in the wind direction and speed before or during the race. It's completely customizable, allowing navigators to pick which data to display, and the length of time and range best suited to their needs.

THE RACECOURSE screen gives a visual picture of the racing area and the boat's track. All vital data can be organized into specific boxes making it easy to access key data about the wind, current, or boat's performance.

bearing to waypoint. This type of layout allows me to quickly glance at the screen and find the information I'm looking for. Set up your display to your liking, but make sure you can quickly retrieve the important information and get your attention back on the racecourse.

On the way to the start, and while we're sailing up the first beat before the start, I use the software package to monitor the conditions via the Data menu by creating my own strip chart. A strip chart is a continuous graphic representation of data. I always display trends for TWD, TWS, TWA, AWA, and current set and drift. Watch for trends in the TWD and TWS during your pre-race routine, and check for winds-hear, which occurs when the wind direction at deck level is different than the wind direction at the top of the mast where the sensors reside. Windshear will cause your AWA and TWA numbers to vary from tack to tack, i.e. wider than normal on starboard and narrower on port. This information is critical to headsail trimmers. In this instance, they would pull their jib car aft on starboard tack to open the top of the sail, and forward on port tack.

One of the best things about strip charts is you can vary the time increments from as little as 5 minutes to several hours. You can also narrow a TWD variable down to a 30-degree range, which gives you 15 degrees each side of the mean, allowing you to get an accurate feel for what's happening with the wind.

Once we're back in the starting area, I sail close by the committee boat and "ping" (locate and input position) the committee boat, which gives me the ability to input the racecourse when the course signals are displayed indicating the range and bearing to the weather mark. In addition, I ping the leeward mark, which is usually a short distance to weather of the starting line. Next, I

switch to the Start Screen and re-ping the committee boat and the pin end of the line to make sure neither have moved.

With all of the marks now recorded, I have a graphical picture of where the course is located on a digital navigation chart. Having the chart displayed is important because in places like Key West, there are often shallow spots near some of the start and finish lines. Running aground while waiting to start is never fast.

Once in the Start Screen, there's a vast amount of information at your fingertips. The on-deck display will switch to a starting area box showing the committee boat, pin, laylines, and favored end. This is great information, especially if the wind is shifting a lot, or if the line is relatively long. Information in the top tool bar is equally important. Here you'll find the time and distance to either end of the line (at reaching trim and speeds) and the time and distance to the line (upwind). Most importantly it has the countdown

Making Sense of the Alphabet Soup

A few common terms used by the digital tactician:

TWD or TD (True Wind Direction): Angle of the wind relative to the surface of the water TWS or TS (True Wind Speed): Velocity of the wind relative to the surface of the water TWA or TA (True Wind Angle): Angle of the wind relative to the centerline of the boat AWS or AS (Apparent Wind Speed): Windspeed measure by the boat's anemometer AWA or AA (Apparent Wind Angle): Wind angle measure by the boat's anemometer Vs (Velocity): Boatspeed

SOG (Speed Over Ground): Boat's speed measured by GPS COG (Course Over Ground): Boat's heading measured by GPS

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to the start with the distance you're ahead or behind the line. The mid-line sag is less of an issue because the starting marks have been pinged with Differential GPS and you can count on the system being very accurate.

Once you're on your way up your beat, and switched to your upwind screen, you can easily tell how square the course is to the wind and the time and distance to the laylines. This can be handy ifone side of the course is strongly favored.With a 2-mile leg, it's hard to call the layline perfectly with a handheld compass, but with the computer you'll be able to narrow down your judgment by taking into account the swings and trends in wind direction.

At this point in the race you should have a feel for the size of the oscillations, which affect the laylines. For example, if the mean true wind direction is 270 degrees, your port tack heading should be approximately 310 degrees. If you're lifted by 10 degrees (TWD 290) the layline would arrive sooner because the port tack layline and bearing to the mark would now be 300 degrees. All these variables must be accounted for when making these crucial calls. Missing a layline call from one of the corners can really be detrimental if you slightly underlay.

"WHAT IF?" SCREEN monitors the boat's position on the course, taking much of the guesswork out of hitting laylines. For each tack, this page displays (top to bottom): heading, course over ground, target boatspeed, average boatspeed, AWA, TWS, TWA, and distance and time-on each tack-to the next mark.

You'll most likely have to tack out to clear your air since the boats just ahead will cross and tack on the true layline thus giving you nothing but bad air.

Approaching the weather mark, it's possible to determine which jibe will be the "long" jibe. If the wind has shifted to the right, and the run is mostly port tack, it may be time for a jibe set around the weather mark. I find the computer most valuable when sailing downwind in lightair, because the TWAs on today's boats change quickly with any increase or decrease in windspeed. It's not unusual to have your target angle change from 141 degrees in 6 knots, to 150 degrees in 10 knots. Being able to nail the layline and sail full speed into the leeward mark will be one of the largest gains you can make on the racecourse.

Keep in mind computers are only as good as the person working them. Maybe one day they'll be able to do everything, but for now tacticians must remember to keep their head out of the boat, and most importantly, communicate with the helmsman and the rest of the team; using tactical software and computers as an aid, not a crutch. ♦

Real-Time Polars

You have the ability to input your polars and targets, which you've developed over the seasons of sailing your boat, into your tactical program, and output your target boat-speed and TWA for the given condition to one dedicated on-deck display. This is a great information because it's based on the sailing conditions, not just a printed diagram taped on the back of the cabin house.

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