Something doesn't add up.....First of all, A 10' jonboat with 3 people and a dog isn't going to be going very quick, certainly not anywhere close to planing - I'm thinking 3 to 5 mph.
Unless you just absolutely can't swim(or you're too drunk to swim), how does one drown? - and if you can't swim, why would you climb into a 10' jon boat???????
I had a 12' jon boat back in the day with a little kicker on the back, and when it was time to take a break and go swimming, we would sink it on purpose, and everyone went for a dip.....no big deal, good clean fun.
I don't get it.
Either way, it sucks. It's heart-breaking when someone suffers a loss while trying to enjoy a nice time out on the water.