Punched a hole in gas tank

[DickOdonovan]

Sea craft my dream boat, I watch the site often love to see a classic returned to better than new. I am coming to you guys because your the best.
I have a 2005 North Coast CC . had a guy ad speakers & amp over the winter. He punched a hole in my gas tank, He either didn't know or didn't tell me. I filled up the tank before launch and discovered gas in the bilge.
The tank is cross link polyethylene I am told this cant be patched, if it can't I was thinking about a "mechanical plug" Any suggestions or recommendations. I will open the deck Monday to see what we are looking at, but I am pretty sure he put the drill through the top! Any help would be much appreciated.
Thanks in advance,
Dick O'Donovan