Yikes! Troubleshooting the Bluefin

There is a saying among folks who work with AUVs (underwater autonomous vehicles, if you recall): They will start any interview by saying, “Damn, damn, damn!” Scott Pegau of the Oil Spill Recovery Institute in Cordova, Alaska, doesn’t begin this way; instead he postpones our interview altogether so he can spend some time troubleshooting his twelve-foot AUV, the Bluefin. This $800,000 dollar piece of equipment is not irreparably broken, but it won’t be able to return to the water tomorrow as scheduled. Four loose screws were all it took to run the vehicle amuck; from there the AUV was unable to steer itself left and right, but it sure tried, causing a small cascade of problems to develop. Pegau, a fellow with a commanding voice, will call the manufacturer tomorrow to solve the problem.

The Bluefin (which is actually yellow) is a torpedo-like instrument that is no stranger to trouble. The last time the team took it out, it hit the bottom of the ship. Today it bears a scar across its back and a bent antenna as testimony to the event.

The Bluefin weighs 750 pounds when dry, 1,200 pounds when wet, and has a positive buoyancy of only ten pounds, making it a very stable mechanism that can easily dive underwater to collect data, up to 3,000 meters (almost two miles) deep. Able to escape the ship’s shadows, it carries mostly optical sensors to measure the light field entering the water. By looking down at the bottom of a swimming pool, you can see how waves focus light; the Bluefin measures this focusing and how it changes as a variable of depth.

Pegau takes turns characterizing the Bluefin with Tim Boyd, a smaller scientist working for the Scottish Association for Marine Science. He is more soft-spoken, but equally passionate about fieldwork. Both particularly enjoy working in the arctic on socially relevant studies, such as climate change and fisheries. “There are several ways to describe oceanography,” Boyd says, “one of which is, you go out to sea, and you throw things overboard until they don’t come back, or you just throw things in until you break them.” Since the Bluefin came back (albeit to the wrong place), perhaps it was fated to break in accordance with Boyd’s theory.