I have a "36" gal. tank in the boat. It has a tag with the information on it. But when i do the calculation of the size it come out to 42 Gallons. I would have to say that the math does not lie. So do i really have a 42 Gallon tank? The reason for this is i got the Lowrance fuel flow sensor and i'm inputing the information to calibrate it so i'm trying to figure out how much fuel is in the tank now. I have about 15 Gals but when i was double checking the math, i came across this problem. Anyone know what's going on????????????