Added DBS to boatdata

boatdata.py

@@ -396,6 +396,7 @@ class BoatData():
         self.xte = BoatValueDistance("XTE", "m")
         self.stw = BoatValueSpeed("STW", "kn")
         self.dbt = BoatValueDepth("DBT", "m")
+        self.dbs = BoatValueDepth("DBS", "m")
         self.roll = BoatValueAngle("ROLL", "deg")
         self.pitch = BoatValueAngle("PTCH", "deg")
         self.yaw = BoatValueAngle("YAW", "deg")
@@ -452,6 +453,7 @@ class BoatData():
             'BTW': self.bearing,
             'COG': self.cog,
             'DBT': self.dbt,
+            'DBS': self.dbs,
             'DTW': self.wpdist,
             'GPSD': self.gpsd,
             'GPST': self.gpst,