diff --git a/model/src/w3nmlbouncmd.F90 b/model/src/w3nmlbouncmd.F90
index 4d8ef25b2..086b6b393 100644
--- a/model/src/w3nmlbouncmd.F90
+++ b/model/src/w3nmlbouncmd.F90
@@ -122,8 +122,7 @@ SUBROUTINE W3NMLBOUNC (NDSI, INFILE, NML_BOUND, IERR)
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlboundmd.F90 b/model/src/w3nmlboundmd.F90
index c17378bf1..665a66f55 100644
--- a/model/src/w3nmlboundmd.F90
+++ b/model/src/w3nmlboundmd.F90
@@ -116,8 +116,7 @@ SUBROUTINE W3NMLBOUND (NDSI, INFILE, NML_BOUND, IERR)
     !/S      CALL STRACE (IENT, 'W3NMLBOUND')
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlgridmd.F90 b/model/src/w3nmlgridmd.F90
index 79271a2b2..fa38b7fa8 100644
--- a/model/src/w3nmlgridmd.F90
+++ b/model/src/w3nmlgridmd.F90
@@ -401,8 +401,7 @@ SUBROUTINE W3NMLGRID (NDSI, INFILE, NML_SPECTRUM, NML_RUN,           &
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlmultimd.F90 b/model/src/w3nmlmultimd.F90
index a37b29f0a..87f338878 100644
--- a/model/src/w3nmlmultimd.F90
+++ b/model/src/w3nmlmultimd.F90
@@ -314,8 +314,7 @@ SUBROUTINE W3NMLMULTIDEF (MPICOMM, NDSI, INFILE, NML_DOMAIN, IERR)
 
     ! open namelist log file
     IF ( NMPLOG .EQ. IMPROC ) THEN
-      NDSN = 3
-      OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+      OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
       IF (IERR.NE.0) THEN
         WRITE (MDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
         RETURN
@@ -479,8 +478,7 @@ SUBROUTINE W3NMLMULTICONF (MPICOMM, NDSI, INFILE, NML_DOMAIN,       &
 
     ! open namelist log file
     IF ( NMPLOG .EQ. IMPROC ) THEN
-      NDSN = 3
-      OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', status='old', iostat=IERR)
+      OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', status='old', iostat=IERR)
       IF (IERR.NE.0) THEN
         WRITE (MDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
         RETURN
diff --git a/model/src/w3nmlounfmd.F90 b/model/src/w3nmlounfmd.F90
index 517cc882e..8f8bb0c0d 100644
--- a/model/src/w3nmlounfmd.F90
+++ b/model/src/w3nmlounfmd.F90
@@ -158,8 +158,7 @@ SUBROUTINE W3NMLOUNF (NDSI, INFILE, NML_FIELD, NML_FILE, NML_SMC, IERR)
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlounpmd.F90 b/model/src/w3nmlounpmd.F90
index 56c11ca05..ef8bd78fa 100644
--- a/model/src/w3nmlounpmd.F90
+++ b/model/src/w3nmlounpmd.F90
@@ -170,8 +170,7 @@ SUBROUTINE W3NMLOUNP (NDSI, INFILE, NML_POINT, NML_FILE,             &
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmloutpmd.F90 b/model/src/w3nmloutpmd.F90
index a8d840886..eebb04860 100644
--- a/model/src/w3nmloutpmd.F90
+++ b/model/src/w3nmloutpmd.F90
@@ -171,8 +171,7 @@ SUBROUTINE W3NMLOUTP(NDSI, INFILE, NML_POINT,              &
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlprncmd.F90 b/model/src/w3nmlprncmd.F90
index 06fa39576..5bd6f3852 100644
--- a/model/src/w3nmlprncmd.F90
+++ b/model/src/w3nmlprncmd.F90
@@ -161,8 +161,7 @@ SUBROUTINE W3NMLPRNC (NDSI, INFILE, NML_FORCING, NML_FILE, IERR)
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmlshelmd.F90 b/model/src/w3nmlshelmd.F90
index 7e0f70dad..6af5a6652 100644
--- a/model/src/w3nmlshelmd.F90
+++ b/model/src/w3nmlshelmd.F90
@@ -301,8 +301,7 @@ SUBROUTINE W3NMLSHEL (MPICOMM, NDSI, INFILE, NML_DOMAIN,            &
 
     ! open namelist log file
     IF ( NMPLOG .EQ. IMPROC ) THEN
-      NDSN = 3
-      OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+      OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
       IF (IERR.NE.0) THEN
         WRITE (MDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
         RETURN
diff --git a/model/src/w3nmltrncmd.F90 b/model/src/w3nmltrncmd.F90
index 0b6dadab6..144eedddf 100644
--- a/model/src/w3nmltrncmd.F90
+++ b/model/src/w3nmltrncmd.F90
@@ -129,8 +129,7 @@ SUBROUTINE W3NMLTRNC (NDSI, INFILE, NML_TRACK, NML_FILE, IERR)
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN
diff --git a/model/src/w3nmluprstrmd.F90 b/model/src/w3nmluprstrmd.F90
index dff43745c..865430b4a 100644
--- a/model/src/w3nmluprstrmd.F90
+++ b/model/src/w3nmluprstrmd.F90
@@ -130,8 +130,7 @@ SUBROUTINE W3NMLUPRSTR (NDSI, INFILE, NML_RESTART, NML_UPDATE, IERR)
 #endif
 
     ! open namelist log file
-    NDSN = 3
-    OPEN (NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
+    OPEN (NEWUNIT=NDSN, file=TRIM(INFILE)//'.log', form='formatted', iostat=IERR)
     IF (IERR.NE.0) THEN
       WRITE (NDSE,'(A)') 'ERROR: open full nml file '//TRIM(INFILE)//'.log failed'
       RETURN