I want to put a kayak in Johnson Creek in Gresham and float west until it reaches the Willamette in Milwaukie. Is that doable? Intrepid Adventurer

Maritime law is one of the oldest branches of the legal profession. As such, not only does it feature entertaining provisions like, "The bosun's groat bucket shall be well-sealed with pitch ere ye be three leagues from port," it often gets to supersede other branches of law by virtue of having been there first.

For example, maritime law is the reason that 1,500 people on the Hawthorne Bridge have to wait for one asshole in a sailboat: The right to a navigable waterway trumps the right to use the road.*

So, Intrepid, I understand why you might conclude that if you can manage to get into some kind of boat, you should be able to get away with murder.

Indeed, if a navigable waterway crosses private property, the owner not only has to let you navigate it, he has to give you access to the stream's banks if you need to get out and walk.

But not so fast, Bear Grylls: The list of Oregon waterways that have been declared navigable is short, and doesn't include Johnson Creek. That doesn't mean you can't try to make your case, but as Julie Curtis of the Oregon Department of State Lands warns: "Navigability declarations [are] very time-consuming and expensive."

But maybe you figure that you'll just wait until the creek is high enough so you won't have to do any portaging. It's true that you have the right to paddle on any Oregon waterway, "navigable" or not, if you stay in the water.

Unfortunately, the further your craft rises from the draggy creek bottom, the closer your face gets to low-hanging obstacles like bridges, branches, and strands of barbed wire. Scout the route first—for God's sake, wear a life jacket—and bear in mind that next year's Darwin Awards are waiting to hear from folks like you. Good luck.

*This was actually the very first Dr. Know question, dealt with here: wweek.com/portland/article-11044-meet-dr-know.html.

QUESTIONS? Send them to dr.know@wweek.com.