I have 316Lss 2 1/4 pipe in a raw water cooling system on two 12v71 detroit diesels aboard a 60 fiberglass boat. It is a new installation with rubber hose connections that passes ocean water after a haet exchanger out the exhaust system. Within a matter of three weeks small pin holes have appeared in some of the the welds in the pipe. The fabricator of the pipes says there is eletrolosis eating away at the welds. The boat is completly bonded with sacrificial zincs on the rudders and shafts. I have metered the bonding system and have a .788 – .795 potential. Is this within range for nominal protection?? Is the rod used for welding the pipe poor ?? Can there be other a/c or d/c currents causing this ??Thanking you in advance for your response.Capt. Dean Adler