I got the idea the website must be wrong because this non-P-trap-but-same-style Attwood flush fuel vent showed it taking a 1-3/8" hole, and plus it only made sense it would have to be a larger hole than the protruding vents.
I got the idea the website must be wrong because this non-P-trap-but-same-style Attwood flush fuel vent showed it taking a 1-3/8" hole, and plus it only made sense it would have to be a larger hole than the protruding vents.