I had large black carpenter ants when I lived in NE. Tons of pine trees around my driveway, and when I opened the boat in the spring (had a bass boat then), there would be hundreds in the keel, apparently they came in through the drain plug that I left out all winter. I started spraying the inside of the keel and making sure the plus was always in. Man, the first year, I hadn't noticed them, lifted the cover on the plug when out on the water, and saw a bunch all climbing around the inside, with nothing I could do way out on the lake. Not fun...so you are not alone! Not a problem where I am now, though...
1996 Prostar 190, LT1
"5 out of 4 people have a problem with statistics..."