diff --git a/ArduSub/Sub.h b/ArduSub/Sub.h
index c4c94b1015..5be239df7a 100644
--- a/ArduSub/Sub.h
+++ b/ArduSub/Sub.h
@@ -53,7 +53,7 @@
 #include <AP_Relay/AP_Relay.h>           // APM relay
 #include <AP_Mount/AP_Mount.h>           // Camera/Antenna mount
 #include <AP_Vehicle/AP_Vehicle.h>         // needed for AHRS build
-#include <AP_InertialNav/AP_InertialNav_NavEKF.h>     // ArduPilot Mega inertial navigation library
+#include <AP_InertialNav/AP_InertialNav.h>     // inertial navigation library
 #include <AC_WPNav/AC_WPNav.h>           // Waypoint navigation library
 #include <AC_WPNav/AC_Loiter.h>
 #include <AC_WPNav/AC_Circle.h>          // circle navigation library
@@ -325,7 +325,7 @@ private:
     uint32_t condition_start;
 
     // Inertial Navigation
-    AP_InertialNav_NavEKF inertial_nav;
+    AP_InertialNav inertial_nav;
 
     AP_AHRS_View ahrs_view;