diff --git a/libraries/AC_AttitudeControl/AC_PosControl.cpp b/libraries/AC_AttitudeControl/AC_PosControl.cpp
index ad15853c02..c107f1fa63 100644
--- a/libraries/AC_AttitudeControl/AC_PosControl.cpp
+++ b/libraries/AC_AttitudeControl/AC_PosControl.cpp
@@ -21,8 +21,25 @@ extern const AP_HAL::HAL& hal;
  # define POSCONTROL_VEL_XY_IMAX                1000.0f // horizontal velocity controller IMAX gain default
  # define POSCONTROL_VEL_XY_FILT_HZ             5.0f    // horizontal velocity controller input filter
  # define POSCONTROL_VEL_XY_FILT_D_HZ           5.0f    // horizontal velocity controller input filter for D
+#elif APM_BUILD_TYPE(APM_BUILD_ArduSub)
+ // default gains for Sub
+ # define POSCONTROL_POS_Z_P                    3.0f    // vertical position controller P gain default
+ # define POSCONTROL_VEL_Z_P                    8.0f    // vertical velocity controller P gain default
+ # define POSCONTROL_ACC_Z_P                    0.5f    // vertical acceleration controller P gain default
+ # define POSCONTROL_ACC_Z_I                    0.1f    // vertical acceleration controller I gain default
+ # define POSCONTROL_ACC_Z_D                    0.0f    // vertical acceleration controller D gain default
+ # define POSCONTROL_ACC_Z_IMAX                 100     // vertical acceleration controller IMAX gain default
+ # define POSCONTROL_ACC_Z_FILT_HZ              20.0f   // vertical acceleration controller input filter default
+ # define POSCONTROL_ACC_Z_DT                   0.0025f // vertical acceleration controller dt default
+ # define POSCONTROL_POS_XY_P                   1.0f    // horizontal position controller P gain default
+ # define POSCONTROL_VEL_XY_P                   1.0f    // horizontal velocity controller P gain default
+ # define POSCONTROL_VEL_XY_I                   0.5f    // horizontal velocity controller I gain default
+ # define POSCONTROL_VEL_XY_D                   0.0f    // horizontal velocity controller D gain default
+ # define POSCONTROL_VEL_XY_IMAX                1000.0f // horizontal velocity controller IMAX gain default
+ # define POSCONTROL_VEL_XY_FILT_HZ             5.0f    // horizontal velocity controller input filter
+ # define POSCONTROL_VEL_XY_FILT_D_HZ           5.0f    // horizontal velocity controller input filter for D
 #else
- // default gains for Copter and Sub
+ // default gains for Copter / TradHeli
  # define POSCONTROL_POS_Z_P                    1.0f    // vertical position controller P gain default
  # define POSCONTROL_VEL_Z_P                    5.0f    // vertical velocity controller P gain default
  # define POSCONTROL_ACC_Z_P                    0.5f    // vertical acceleration controller P gain default