Seal line 115L dry bag backpack

I'm figuring I'd use it for shit weather camping, general travel, and some normal overnighters/multi-day trips. I don't paddle but there are a few lakes with beautiful islands I swim to but can't get my gear to.

is 115L comically large? I reckon I'd be able to fit all my gear including small axe.
currently on sale for $120 at my local gander mtn.