We have a 19' Smokercraft - bought new in 2006 (2005 model). We boat in salt water in the Puget Sound WA every summer about 10-15 times, boat is stored in a garage, cleaned regularly. We are suddenly developing multiple holes in the hull, some the size of a nail hole. Have read some about electrolysis and salt water. The only electrical changes we made was installing a power inverter last summer. We have zinc fittings on the motor. What could be causing this and how should we repair? This just has happened in a matter of weeks - went from one hole to 4 more. Help!