Re: almost blew up!!! scary!!
I worked at a marina 20 some odd years ago as a gas dock attendant. Had one boat come in, it was probably a 26 foot or so cuddy if memory serves. He had docked with the fuel filler on the other side - and didn't invite me to come aboard with my filler and hose. Rather, he held his hand up to take it, so I handed it to him. He went to the other side of the cuddy where the filler was, whipped out his 2-dowel fuel cap key, opened up the cap and started filling. It immediately started burbling back up, like the vent wasn't working properly. He tried for several minutes to get it to take fuel. At this point, I asked if I could try. I climbed aboard and took a peek over the far gunwale - at which point I noticed the deck fitting for the filler said "WATER". He had been pumping gas into the onboard water tank. About 1 foot aft of the water filler was the "GAS" filler fitting, cap still firmly in place. We spent the afternoon siphoning out the gas & water mix, flushing it with soapy water, and repeating until the owner finally said good enough. I never saw him again after that, so I don't know if it damaged his water system or not...
Anywa, schtuff happens.