It was probably named a boilermaker because it was popular with blue-collar folks like iron workers...just a guess, I don't really know.
How do you make a ship's boiler? Weld curved steel panels, from the outside, then from the inside. From the inside, it gets very hot, so hot that the sweat that drops to the boiler floor, turns to steam. Newport News is where they made the ships back when. Now, a shot and a beer used to be a favorite of the Boiler Maker's union when at the local bars. But, they only had so much time they were allowed to spend there. Having a beer was OK, having a whiskey was frowned on. So the bartender would have the glasses lined up below the bar level with the shot already poured. That way they could draw the tap and just add beer to the glass. Union Stewards were happy and the guys came back after work to toss a few more to get rid of the terrible headaches (hangovers) So now, as Paul Harvey would say, you know the rest of the story.
I think that's what it does to your stomach.
