Seems like, as with any physical problem, the number of second-order variables that are unseen have first-order effects. Generally, in dealing with tidal currents in Puget Sound, the outside of the bends is the faster track when going with the current. However, local knowledge has saved us many times.
There is a locally well known passage, known as Colvos Passage, up the west side of Vashon Island, that always flows north, even when the flood is proceeding south. If you look at a chart of the area around Vashon, the main flood current proceeds along the much wider and deeper east passage, down the east side of the island, and the fluid dynamics and topography make for a 'downhill run' for the water northward in Colvos. Backeddies can be your friend.
Exploring the Salish Sea