That’s interesting. I had been thinking of the Great Lakes. On one of my trips to Chicago I was walking about the waterfront by the marina which is near to the Drake Hotel (if you know it?). It was quite choppy that day, and the lifeguards were not allowing boats to leave the marina.
One of the things I observed was the way the water seemed to rebound from the seawall (for want of a better description). Britain has seawalls along parts of its coastline, but the effect was different. The lake water had no place to go, so it merely went back on itself, creating steep troughs which were rather compact and dangerous looking. Here, the current usually creates an undertow so the effect is more cyclical, with much longer wavelength than I observed on Michigan. Considering that wave action, I can imagine how true your comments about ship losses are.
Another thing was that there was no foam. Presumably the water is fresh water i.e. no brine? I suppose that would account for it and also for the lack of the smell of the sea, which is actually caused by rotting seaweed.
I was also wondering whether the lake has an effect on the local climate, producing mild winters and cooler summers as in Britain, but I expect not as the currents around the British coast are South Westerly which originate in the Caribbean bringing warmer air and, of course, rain. 
Perhaps one of our sciency chaps can explain it better.
