Mine is above the rub-rail on the side of the boat and and some (older models) are below the rub-rail on the back of the boat. Mine points to the back of the boat so If water comes over the rail while moving it wont go straight in. But for xtra protection I also clog mine at the gas station after I fill it up. I take a lil paper towel and tear off a pc and stuff about 6" of it in there with a screw driver. You have to take it out to fill up. The gas vent hose a literally 12' long so if your tank sits in the sun and heats up when its full it will swell and spit it out of the vent, also cornering will make it spit out too so clog it!! There is a vent hose valve made for boats and this problem but it was $99 for the $5 part since it said Marine on it so I passed on buying it. lol. Sounds like you will be pulling your tank now.