Operator of boat was thrown overboard when boat rolled over after being hit by large wave from the side.  Operator was not wearing a pfd at the time.  He attempted to swim back to overturned vessel but was unable to because of strong current.  Victim was wearing neoprene chest waders and a Gortex jacket.  The waders kept him warm and he was able to seal air in the jacket in a manner that provided some floatation.  Operator spent almost 5 hours in 62 degree water.  
Ipswich                       