Sounds the same as the trip I had, though the ferry was not a catamran, and was definitely not high speed.
The difference between high and low tides is still the most memorable part to me. I am a North Carolina native and accustomed to the high and low tides we have here. I would not want to be in the area if they had a hurricane,because the storm surge would unbelievable.
Did you happen to "do" Lunenburg? I thought it was a fascinating seaport/small town. The museum there has a chapel with the names of those lost at sea over the last 100 years or so. So many names were the same - whole families lost at sea. Sad, but interesting.