Rover: rename nav_enabled to tack_enabled

tack_enabled is more precise than nav_enabled so it describes the feature more accurately

APMrover2/mode_loiter.cpp

@@ -25,7 +25,7 @@ void ModeLoiter::update()
     // if within loiter radius slew desired speed towards zero and use existing desired heading
     if (_distance_to_destination <= g2.loit_radius) {
         // sailboats should not stop unless motoring
-        const float desired_speed_within_radius = rover.g2.sailboat.nav_enabled() ? 0.1f : 0.0f;
+        const float desired_speed_within_radius = rover.g2.sailboat.tack_enabled() ? 0.1f : 0.0f;
         _desired_speed = attitude_control.get_desired_speed_accel_limited(desired_speed_within_radius, rover.G_Dt);
     } else {
         // P controller with hard-coded gain to convert distance to desired speed

APMrover2/sailboat.cpp

@@ -97,7 +97,7 @@ Sailboat::Sailboat()
 }
 
 // Should we use sailboat navigation?
-bool Sailboat::nav_enabled() const
+bool Sailboat::tack_enabled() const
 {
     return (enable == 2) &&
            (throttle_state != Sailboat_Throttle::FORCE_MOTOR) &&
@@ -111,7 +111,7 @@ void Sailboat::init()
         rover.g2.crash_angle.set_default(0);
     }
 
-    if (nav_enabled()) {
+    if (tack_enabled()) {
         rover.g2.loit_type.set_default(1);
         rover.g2.loit_radius.set_default(5);
         rover.g2.wp_nav.set_default_overshoot(10);
@@ -224,7 +224,7 @@ float Sailboat::get_VMG() const
 // handle user initiated tack while in acro mode
 void Sailboat::handle_tack_request_acro()
 {
-    if (!nav_enabled() || currently_tacking) {
+    if (!tack_enabled() || currently_tacking) {
         return;
     }
     // set tacking heading target to the current angle relative to the true wind but on the new tack
@@ -243,7 +243,7 @@ float Sailboat::get_tack_heading_rad() const
 // handle user initiated tack while in autonomous modes (Auto, Guided, RTL, SmartRTL, etc)
 void Sailboat::handle_tack_request_auto()
 {
-    if (!nav_enabled() || currently_tacking) {
+    if (!tack_enabled() || currently_tacking) {
         return;
     }
 
@@ -262,14 +262,14 @@ void Sailboat::clear_tack()
 // returns true if boat is currently tacking
 bool Sailboat::tacking() const
 {
-    return nav_enabled() && currently_tacking;
+    return tack_enabled() && currently_tacking;
 }
 
 // returns true if sailboat should take a indirect navigation route to go upwind
 // desired_heading should be in centi-degrees
 bool Sailboat::use_indirect_route(float desired_heading_cd) const
 {
-    if (!nav_enabled()) {
+    if (!tack_enabled()) {
         return false;
     }
 
@@ -284,7 +284,7 @@ bool Sailboat::use_indirect_route(float desired_heading_cd) const
 // this function assumes the caller has already checked sailboat_use_indirect_route(desired_heading_cd) returned true
 float Sailboat::calc_heading(float desired_heading_cd)
 {
-    if (!nav_enabled()) {
+    if (!tack_enabled()) {
         return desired_heading_cd;
     }
 

APMrover2/sailboat.h

@@ -27,7 +27,7 @@ public:
     bool sail_enabled() const { return enable > 0;}
 
     // true if sailboat navigation (aka tacking) is enabled
-    bool nav_enabled() const;
+    bool tack_enabled() const;
 
     // setup
     void init();