If it's like my boat (2001 Challenger) there's a smaller diameter hose coming off the tank between the large filler hose and the fuel baffle (that thing in the middle with 4 hoses coming out). That's the overflow pressure release.
I don't like gas coming out either place, so I usually open the engine compartment and watch the gas fill, slowing when near full and stopping before it back up the filler hose. The auto cut-off on gas pumps doesn't work reliably like it does filling your car.