I have been having problems with my Hunter 216 Hydraulic Integrals. I have a fleet of 3 2006 216s which have been needing their integrals rebuilt annually. They are moored every season and kept with the center board up when they are not in use due to the current. Typically all three integrals will not last the season and need to be rebuilt either because of oil loss or repeated airlock. Any suggestions would be welcome. Thanks!