Brockville — St. Lawrence

Charters leave the Brockville waterfront in small, fast boats, and the run out is short enough that the briefing takes longer than the ride. Each dive is planned before anyone gets wet: which end of the hull you land on, which way the river will push you, where the pickup happens. Crews work around commercial traffic as well, since this is a working seaway channel and a laker will not be altering course for a dive flag. The boat's job is to be downstream when the marker comes up.

The bottom is ledge and gravel rather than sand, and the ships sit in whatever shelter it gives them. Some are tucked against a bank or behind an island where a back-eddy takes the sting out of the flow; others lie fully exposed. That, more than depth, is the real difference between sites: on the sheltered hulls you can stop, hold onto something and look into things, while the exposed ones are read at whatever speed the river has chosen. The inverted wrecks change the geometry again, with the hull overhead and the detail along its edges.

It is an unforgiving place to learn and a rewarding one if the skills are already there. Cold fresh water means a drysuit for most of the season, hood and gloves, and enough spare attention to deploy a marker while still moving. Photographers find it hard, since there is no station-keeping and no swimming back upstream for a second look. Divers who like planning, wreck history and the physical feel of moving water do very well, and most visitors dive two or three days from the same dock.