We’ve used the collapsable square traps and had limited success. For the most part we do our crabbing by wading and snorkelling. We like to find a little cove with eel grass that has a large tidal exchange(no PSP risk). If you find a public dock or want to crab from your dinghy our new favorite is the Frisbee/Taco style. They look like a frisbee with a mast. When you pull the line(through the eye at the “masthead”) the trap folds up like a taco. Very successful at Fernwood Dock just south of Kuper Is on Salt Spring.
If you take your dinghy through “the Cut” from Telegraph you come into Clam Bay(Cove) it’s more inset into Kuper than Thetis. Near the private dock there’s an underwater “wall”. We took some huge Rock Crab there snorkelling(below high water is public domain 😉 ). If you search around and find some eel grass with 10+ ft depth at low water you can get some Dungeness. They’re bigger but our whole family finds Rock Crab sweeter.
I’m not a good deepwater crabber, lost our bait so often its frustrating.
Note that it’s been a lousy year for crabbing and Dungeness prices have passed Lobster prices here.