diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 0666a418..5a5cb7d6 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -74,8 +74,9 @@ def timedeltaconv(x):
     if not np.isnan(x):
         dt = datetime.timedelta(seconds=x)
     else:
-        dt = 350.
-
+        dt = datetime.timedelta(seconds=350.)
+        
+        
     return dt
 
 def rdata(file,rower=rrower()):