I am in a 17' Bass Tracker converted into a duck boat. I fish West Sister, Even North of West Sister. Wave forecast must be 2' or less before I head out there. I have been caught in 6 to 8's. Not fun! Long ride home. Don't take the swells head on. Hit at 45 degrees and power up, otherwise it will push you back in the valley. I have a 75hp, which is good power for my small boat to climb out of the valley. One thing you must do if you decide to venture out, is get a marine radio with distress signal capability. You will also need a GPS that will communicate with the radio. This will give you comfort knowing the coast guard is easily available, and your location is communicating electronically. Also, you must have an electric bilge pump that is auto or switch activated. When you do take water from a wave, you don't want to divert your attention from piloting to pumping water out manually. Not recommending you go out past your comfort point, but West Sister is reachable in 17' boat. I agree with tadams. Once you see froth on top of the waves, you know it will be a rough ride.