I started during my first enlistment, around 1981 or so. It had a lot to do with the fact that if you smoked....you got a lot more breaks during the work day. Back then...I was 10 feet tall, and bullet proof. So I had no worries. 25 years later....I have got to put them down. Soon.
I started smoking right out boot camp, late 2001. It still works the same way as patrick was saying...they don't have "go chat with your buddy" breaks, just smoke breaks.
Its still the same thing today, on my ship its cool if you dip out for 15-20 to smoke but if you dont you get labled a slacker if your gone that long without an excuse
25 years later....I have got to put them down. Soon.