FREQUENTLY ASKED QUESTIONS
A: Ideally, you have sailed out to the race course area well before the scheduled time of the first warning signal. It is a good practice to sail upwind on both tacks, to build up a comprehensive set of observations about the wind direction. The goal is to discover the full range of the oscillations in the wind direction, from the furthest left to the furthest right, on both tacks.
As you sail upwind, note the heading on the boat’s binnacle, bulkhead or mast compass, and tap the heading into the keypad. Remember that all compass headings must be three digits, so start with a 0 for headings between north and east. For due north, enter 000 not 360. Values greater than 359 are not accepted. On the next screen, tap “Port” or “Starboard” according to the tack that you are sailing on. The “Upwind/Downwind” slider defaults to “Upwind” until you change it. Note that the tacking angle is set by default to 90 degrees. Most modern boats can do better than this. If you know your boat’s performance characteristics in the prevailing conditions, change the tacking angle to the correct value. The more accurately you can preset the tacking angle, the less “tacking” there will be in the true wind direction that the North U. Tactician app infers from the raw data that you input.
A: The wind direction is never perfectly steady, but shifts to the left and right of its average direction. It is to this average wind direction that a race official strives to align the course axis of a typical windward-leeward race. Your goal as tactician is to identify the headings on port and starboard tack that correspond to this average wind direction.
A good place to start is the mid-point on each tack between the highest and lowest headings you have recorded on each tack. After collecting several points of data on both tacks, tap the compass button that appears below the history table. The “Upwind medians” calculator screen displays the highs and lows on both upwind tacks, and initially finds the mid-points on both tacks. The screen displays the tacking angle implied by the two mid-points. If this tacking angle is not what you would expect for your boat in the current conditions, this is a sign that your wind observations have, through dumb luck, collected only starboard tack headings when the wind was primarily left of its average direction and port tacks when the wind was primarily right of its average direction (too broad of a tacking angle), or the obverse (too tight of a tacking angle). With the tacking angle set to “Unlock”, manually adjust the port and starboard median headings with the plus and minus buttons until you have both a tacking angle and a median true wind direction that seems right to you. The aim is select port and starboard tack upwind medians that are both related to the same average or median wind direction by the optimum VMG true wind angle for the boat in the prevailing wind conditions. Lock the tacking angle and tap “Set” to save.
A: There are several ways to know what is the optimum true wind angle for your boat for the conditions. 1.) You could consult polar diagrams as supplied by the boat’s designer. 2.) In very steady conditions, you could record your heading on a close-hauled course, bring the boat about to the other tack, and — after allowing enough time for the boat come up to speed and settle in to the optimum close-hauled course — record the boat’s heading on the new tack and calculate the angle between the port and starboard tack upwind headings. 3.) Two identical boats with similar sail trim sailing upwind on opposite tacks in close proximity could relay each other’s compass headings over VHF radios.
A: The North U. Tactician app allows you to record a true wind speed for reference so that you can look for patterns, such as puffs generally veering to the right. Use the information coming from your boat’s wind instruments, or base your input on what you see on the water. A good rule of thumb is that whitecaps typically start appearing in flat water at around 12 knots of true wind. The true wind speed slider stays at the value that you last used.
A: The vertical line represents the true wind direction that you have set on the median wind direction calculator screen (accessed via the ‘compass’ button).
A: The left and right arrows are on either side of the vertical line adjust the median true wind direction left or right in one degree increments. You generally want the vertical line to divide evenly the range of wind direction values plotted on the graph since the baseline time. If the wind readings fall in a pattern that is somewhat skewed to one side or other of the vertical line, you can use the right or left arrows to adjust the line to a position that more evenly splits the range of wind readings. The right and left arrows change the value of the median true wind direction, and so the median headings on port and starboard tack change accordingly. You can confirm this by going back to the median wind direction calculator screen (accessed via the ‘compass’ button). The right and left arrows are by design small buttons to tap, so that you do not change the key tactical benchmarks inadvertently.
A: For ease of reading in all lighting conditions.
A: You can correct data entry errors for any observation by tapping and holding on its row in the history table. This opens up a page for editing that observation. You can revise the heading, change the tack from port to starboard, or make whatever other correction required. Remember to tap “Save.”
A: The North U. Tactician app can adjust the tactical analysis to take into account major changes in the wind. Tap and hold a row in the history table bring up the screen for editing that observation. Tap “Make this observation the baseline.” The North U. Tactician app will thereafter base its tactical analysis of the high and low headings on port and starboard tack on readings since that baseline time. The baseline time is highlighted in the history with a shaded row. It is also highlighted with a horizontal line on the graph of the same shading.
When you have changed the baseline time, it is a good idea to tap the compass button to revise the median port and starboard headings. Tap ‘avg’ on one tack to move the median heading to the mid-point between the new high and new low on that tack, as calculated since the new baseline time. If the tacking angle is locked, the ‘avg’ button on one tack will find the mid-point on that tack, while the median on the other tack will move to maintain that locked tacking angle. If the tacking angle is unlocked, the midpoints on port and starboard will be independent of each other. Adjust the medians manually with the plus and minus buttons as required.
You can always move the baseline to a prior observation. Observations prior to a baseline time are not deleted; they are merely not used for the purposes of finding the high and the low on a tack.
A: The North U. Tactician app currently is designed to assist with upwind tactics. Downwind legs are more of a challenge to tacticians because true wind angles vary widely with wind speed, and the clues that one is not sailing at the optimum angle to the wind are much more subtle. Consequently, it is difficult to use the boat’s heading to track trends in the true wind direction reliably. Look for future versions of North U. Tactician to address downwind tactics. For now, though, you can still keep track of the boat’s heading on port and starboard gybe downwind. Select the “Downwind” option on the slider on the data entry screen. Downwind headings appear in the history table in light grey. True wind directions are not calculated for downwind numbers, so though there will be entries in the history table, there will not be true wind directions plotted on the graph.
You can also use the “Mark” button to demarcate legs of the course. A triangular ‘mark’ icon will appear in the history list, and a horizontal line will appear on the graph to indicate the mark rounding. Remember to move the slider back to “Upwind” when you round the leeward mark.
A: Check to see that you have only entered downwind headings. Downwind numbers are shaded grey. Change the “Upwind/Downwind” slider on the data entry screen to “Upwind”. The slider will remain on the last value you used. You can open each row of data to edit by tapping and holding, and then change each record from “Downwind” to “Upwind” with the slider.
A: Check to see that you did not just enter a downwind heading. The tactical analysis pop-up only appears for upwind headings.
A: The only way is to enter a new heading. This is not so bad; your overall analysis of the trends in the wind will improve with more data points.
A: If you keep track of port and starboard headings with a pad and pencil, you can use the North U. Tactician app. It is just as quick to enter a heading, and you don’t need to write down the time. The North U. Tactician app has more features that will help you get more value out of the history of port and starboard numbers you have built up, if you can devote more attention to your iPhone. At the very least, the North U. Tactician app replaces handwritten notes with neat, scrollable columns.
A: Yes. iPod Touch, too.
A: There are a number of splash-proof cases for iPhone, by manufacturers like Otter Box, Pelican, Aquapak, Duogreen, SealLine and others.
A: No, for three reasons:
1. The heading data you get from the iPhone’s internal GPS is not especially accurate, and its lag in time is too much to be a useful tactical tool.
2. A GPS lacks human insight. Is your boat in dirty air? Helms-person momentarily inattentive? You know not to record those headings, but a GPS will. What about tapping a button when you want to input a heading, which takes the heading at that instant from the internal GPS? See reason 1., above.
3. Some classes (e.g., J/22, J/24, Etchells) disallow using a GPS for information on the boat’s heading.
The North U. Tactician app is not intended to replace existing sources of tactical information such as the boat’s compass and wind instruments, but instead help the tactician keep track of and manage the data that these established tools are producing. The North U. Tactician app takes what you write in WetNotes or on your gelcoat and puts it in your iPhone. North U. Tactician then frees you from having to keep several compass headings in short-term memory and from all the mental arithmetic. This helps you make better decisions because instead of juggling numbers, you are able to focus on the big picture of the trends in the true wind direction.
A: A handheld compass is not repeatable enough for accurate information on the boat’s heading. The fluxgate compass internal to the iPhone is not particularly accurate, and the mobile device lacks lubber lines. There is also the issue of how accurately and repeatably you can point it parallel to the boat’s heading. Every race boat has a compass at the mast or on the bulkhead. Why reinvent the wheel? Or in this case — the compass.
A: This is a simple app, intended to take the compass information that a tactician already monitors, and put it in an app that manages the data, displays it clearly, reduces the short-term memory burden, and assists with the mental arithmetic.