The Mystery of Devil's Kettle Falls
I'm reading this and wondering why you couldn't build a waterproof beacon?  At least by tracking it you could prove that it didn't exit into Lake Superior.<p><a href="https://en.wikipedia.org/wiki/Underwater_locator_beacon" rel="nofollow">https://en.wikipedia.org/wiki/Underwater_locator_beacon</a><p><a href="http://www.rjeint.com/aviation-underwater-locator-beacons" rel="nofollow">http://www.rjeint.com/aviation-underwater-locator-beacons</a>