San Juan Islands, Washington state. Notorious for the currents, fog, and big ship traffic. Tide and current tables a must. At least the sailboat had the luck to be able to turn around without landing on a rock.
I really, really do not like passes like that.
Hell Gate in the East River, New York City is a bit like that. A bit scary because of the eddies and whirlpools. One must pay attention. People refer to it as Hell's Gate, but it's from the days when NYC was Nieuw Amsterdam, and helle meant "bright." Lots of dutch names in the area.