added "tack" field to "showboatpositions" output, added corresponding doc to README

java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/TrackedRace.java

@@ -201,7 +201,7 @@ public interface TrackedRace {
      * Determines whether the <code>competitor</code> is sailing on port or starboard tack at the
      * <code>timePoint</code> requested.
      */
-    Tack getTack(Competitor competitor, TimePoint timePoint) throws NoWindException;
+    Tack getTack(Competitor competitor, TimePoint timePoint);
 
     TrackedEvent getTrackedEvent();
 }

java/com.sap.sailing.domain/src/com/sap/sailing/domain/tracking/impl/TrackedRaceImpl.java

@@ -597,7 +597,7 @@ public abstract class TrackedRaceImpl implements TrackedRace, CourseListener {
      * For the unlikely case of 0 degrees difference, {@link Tack#STARBOARD} will result.
      */
     @Override
-    public Tack getTack(Competitor competitor, TimePoint timePoint) throws NoWindException {
+    public Tack getTack(Competitor competitor, TimePoint timePoint) {
         Bearing wind = getWind(getTrack(competitor).getEstimatedPosition(timePoint, /* extrapolate */ false), timePoint).getBearing();
         Bearing boat = getTrack(competitor).getEstimatedSpeed(timePoint).getBearing();
         Bearing difference = wind.getDifferenceTo(boat);

java/com.sap.sailing.server/src/com/sap/sailing/server/ModeratorApp.java

@@ -116,6 +116,7 @@ public class ModeratorApp extends Servlet {
                         jsonFix.put("lngdeg", fix.getPosition().getLngDeg());
                         jsonFix.put("truebearingdeg", fix.getSpeed().getBearing().getDegrees());
                         jsonFix.put("knotspeed", fix.getSpeed().getKnots());
+                        jsonFix.put("tack", trackedRace.getTack(competitor, fix.getTimePoint()).name());
                         jsonFixes.add(jsonFix);
                     }
                     jsonCompetitor.put("track", jsonFixes);