diff --git a/conda_package/mpas_tools/__init__.py b/conda_package/mpas_tools/__init__.py
index cfd74488f..a146677a5 100644
--- a/conda_package/mpas_tools/__init__.py
+++ b/conda_package/mpas_tools/__init__.py
@@ -1,2 +1,2 @@
-__version_info__ = (0, 5, 0)
+__version_info__ = (0, 5, 1)
 __version__ = '.'.join(str(vi) for vi in __version_info__)
diff --git a/conda_package/mpas_tools/ocean/moc.py b/conda_package/mpas_tools/ocean/moc.py
index d1d34f873..f90b3d97c 100755
--- a/conda_package/mpas_tools/ocean/moc.py
+++ b/conda_package/mpas_tools/ocean/moc.py
@@ -290,15 +290,13 @@ def _add_transects_to_moc(mesh, mocMask, southernBoundaryEdges,
     mocMask['transectVertexGlobalIDs'] = \
         (('nTransects', 'maxVerticesInTransect'), transectVertexGlobalIDs)
 
-    mocMask['transectNames'] = mocMask.regionNames.rename(
-        {'nRegions': 'nTransects'})
-
     if 'nRegionsInGroup' not in mocMask:
         nRegions = mocMask.sizes['nRegions']
         nRegionGroups = 2
         nRegionsInGroup = nRegions*numpy.ones(nRegionGroups, dtype=int)
         regionsInGroup = numpy.zeros((nRegionGroups, nRegions), dtype=int)
         regionGroupNames = ['MOCBasinRegionsGroup', 'all']
+        regionNames = mocMask.regionNames.values
         nChar = 64
         for index in range(nRegionGroups):
             regionsInGroup[index, :] = numpy.arange(1, nRegions+1)
@@ -315,6 +313,17 @@ def _add_transects_to_moc(mesh, mocMask, southernBoundaryEdges,
         for index in range(nRegionGroups):
             mocMask['regionGroupNames'][index] = regionGroupNames[index]
 
+        # we need to make sure the region names use the same string length
+        mocMask['regionNames'] = \
+            (('nRegions',), numpy.zeros((nRegions,),
+                                        dtype='|S{}'.format(nChar)))
+
+        for index in range(nRegions):
+            mocMask['regionNames'][index] = regionNames[index]
+
+    mocMask['transectNames'] = mocMask.regionNames.rename(
+        {'nRegions': 'nTransects'})
+
     mocMask['nTransectsInGroup'] = mocMask.nRegionsInGroup.rename(
         {'nRegionGroups': 'nTransectGroups'})
 
diff --git a/conda_package/recipe/meta.yaml b/conda_package/recipe/meta.yaml
index 95285d86c..cc86cba19 100644
--- a/conda_package/recipe/meta.yaml
+++ b/conda_package/recipe/meta.yaml
@@ -1,5 +1,5 @@
 {% set name = "mpas_tools" %}
-{% set version = "0.5.0" %}
+{% set version = "0.5.1" %}
 
 package:
   name: {{ name|lower }}