That sonar-equipped, self-propelled seafloor-mapping device caused a stir along Alki Avenue this afternoon, then again tonight. Around midafternoon, its owners say, it failed a test; then someone apparently mistook it for an overturned kayak and rescuers briefly responded. It wound up on the beach in the 1300 block of Alki — where some passersby wondered if it were a “torpedo” — and there it stayed till a crane could be brought in a short time ago to retrieve it:

It couldn’t just be carried off the beach, its owners explained, because it weighs 1300 pounds. (Here’s a little more about it.) So they had to summon the crane (and police came out to be sure it could get close enough to the seawall, safely). 9:12 PM UPDATE: Adding video of the crane operation. (Note, the mapping device achieves liftoff about 49 seconds in.)