 
 // minimum speed needed to establish course (knots)
 #define MIN_SPEED 1.0
+#define MIN_TACK_SPEED 1.0
 
 // how close you have to get to the waypoint to consider it hit
 #define GET_WITHIN 5

#define WIND_LOOKAHEAD 10

// either side of 0 for "in irons"
#define IRONS 40
#define IN_IRONS(v) (((v) < IRONS || (v) > (360 - IRONS)))
#define TACK_TIMEOUT 10000


        if (!skip_irons_check && IN_IRONS(new_wind)) {
            logln("Requested (new wind %d) course unsafe, requires tack", new_wind);
            // and if we're allowed to tack, we tack
            if (CAN_TURN() && gps_speed > MIN_TACK_SPEED) {
                logln("Tack change allowed. Turning.");
                tack();
                last_turn = millis();
