Another boat question

....There are only a couple of times in my life that a machine left an indelible impression on me.

My dad and I used to drive down from our crummy south Miami neighborhood to fish under several bridges in the Keys often. I had seen the giant racing boats that required a semi a few times but one evening a Cigarette with what appeared to be 3 inboard motors was heading out into the Atlantic from the Gulf as the sun was setting. I don't think it was racing. They were just exercising it let's say. Now anytime a boat went under the bridge it kinda echoed anyway. When this thing went through it was tremendous and then they opened it up and took off. It seemed like you not only could hear it until it went over the horizon, you felt it. I was fifteen.