diff --git a/ArduSub/Sub.h b/ArduSub/Sub.h
index 5a8493d154..135c42ac39 100644
--- a/ArduSub/Sub.h
+++ b/ArduSub/Sub.h
@@ -422,7 +422,6 @@ private:
     float get_surface_tracking_climb_rate(int16_t target_rate, float current_alt_target, float dt);
     void update_poscon_alt_max();
     void rotate_body_frame_to_NE(float &x, float &y);
-    void send_heartbeat(mavlink_channel_t chan);
 #if RPM_ENABLED == ENABLED
     void rpm_update();
 #endif