NIce videos, the Keystorm is a great dive, it depends what the OP means by 'have only one morning'. Every Canadian charter operator I've been on pre-registers passport information but the stop at Boldt Castle to clear US immigration still adds about half an hour to the trip (cool castle and boathouse though) and the wrecks are a little farther away. The boat usually does not get back to the dock until early afternoon but a Keystorm - Kinghorn trip out of Rockport might get you back earlier, Kinghorn is a nice little wreck within sight of the dock at Rockport. If time really is limited a Lillie - Gaskin run out of St. Lawrence Park in Brockville will get you back pretty early, I prefer the Lillie to the Muskie, and The Gaskin is a nice easy dive, late 19th century wooden barque, she's upright and she still has quite a bit of structure, I don't reccomend trying to swim there from shore on a single 80 though. There is a lot of great divng in the Brockville/Rockport area, one morning will hopefully just whet the OPs appetite for more.