diff --git a/bbn_m5tough_active_boat/ship_data_model.h b/bbn_m5tough_active_boat/ship_data_model.h
index 20be32a..2d386fe 100644
--- a/bbn_m5tough_active_boat/ship_data_model.h
+++ b/bbn_m5tough_active_boat/ship_data_model.h
@@ -33,6 +33,7 @@ extern "C" {
     GROUND_WIND_TRUE = 9,
     COG_MAG = 10,
     COG_TRUE = 11,
+    NAV = 12,
   } ap_mode_e;
 
   typedef enum {