I take it a "rip" is disturbance between incoming and outgoing tide?

A tidal rip is when you have two currents either moving in oposite directions or one is moving faster then the other. What you get is an area of slack or swrilling water where weeds, sticks, logs and things get trapped. Also what get's sucked into these long lines are plankton and krill. Bait fish also get sucked into these rips or fallow their food. Therefore salmon, especially coho, will hunt along these rips looking for bait fish. A great places to fish off of shipwreack for coho.... I hope that answers you question.

Thanks, Fishingjunkie15

Some folks troll along the rips, but I prefer to crash through them at a 90 degree angle. You collect less salad on your gear that way.