Gasoline is nothing to play with - I am very particular when fueling my boat, generally do it alone, I pump the fuel and don't let the dock hands rush me away when I am done. Ignore the often bad advice to run your blower while you are fueling -- it stays off, turn it on AFTER you have fueled, running it while you are fueling can actually pull fumes INTO the bilge - when you are done, let everyone just wait while you open the engine hatch and inspect.
Embarrassing / stupid thing I did some years ago that reminded me how dangerous it is. At our lake house there was a common burn pile that the neighbors used and different people would light it off from time to time. One winter weekend I had put a bunch of yard debris on the pile and decided I would light it off. Could not find any lighter fluid or kerosene, so I splashed a little gasoline on it - 3-4 splashes around the pile - less than 1gal total (really did not need to put anything on it, but I did). I take a min or two to carry the can back to my truck etc - I took a fire lighter stick to light the pile - which the fumes had now had time to build up in. That thing exploded into a fireball! Thank god I had on boots, jeans, hat, gloves, long sleeve shirt - I didn't get hurt, but had a nice sunburn on my face and singed eye brows. Without the clothing I would have been in trouble. I stupid thing to do, I knew better, and it was a scary reminder.
Seeing the deck blow off that boat does not surprise me - that thing was full of fumes.