Re: plugs
The only hole you need to plug is the drain hole. It is the one nearest the V or keel of the boat. If you look in it you should see the inside of your boat.
The other holes have a big plastic ring and are used for livewell pickups or bilge drains. The drain hole has a thinner ring around it and is pretty obvious of its purpose.
Sounds like you need to get a bit more familiar with your boat before your next launch...Better to be safe than sorry. Kinda like running out of fuel...
"Know your roll"
Good Luck and Play Safe!!!!
Will