Tuesday, November 9, 2004 Matthew A. Russell has been an archeologist with the National Park Service Submerged Resources Center since 1993. He serves as Project Director for the USS Arizona Preservation Project.

Back in the Water. . . Again.

USS Abraham Lincoln departs Pearl Harbor. Photo by Brett Seymour, NPS.

After spending yesterday in transition, that is, moving from one phase of the project to the next, our ambitions for an early start were thwarted once again by the US Navy. This morning USS Abraham Lincoln, which arrived last in port last week, departed and the harbor was locked-down tight as a drum until 0930. On a positive note, this give me the opportunity to Fed Ex the SonTek wave/current meter back to the factory after discovering yesterday it has some, shall we say, issues. Once we got back to the Memorial and into the water on Arizona, we were in for a second not-so-pleasant surprise:  apparently due to the torrential rain we had last week, visibility was worse than any of us have every seen it. That, plus the absolute lack of wind, which means the leaking oil doesn’t disperse, but instead pools on the surface of the water above the ship, made for a less-than perfect series of dives.

A single image to incorporate into the photomosaic. Photo by Brett Seymour, NPS.

Dave and Brett got to try out their photo frame, and began the task of shooting images for the photomosaic. The idea is to shoot many overlapping digital images, and then stitch them together in Adobe Photoshop. Photomosaics have been around for as long as underwater archeology, but the results are hit or miss. To get a precisely accurate image takes enormous effort and control, and often means constructing an elaborate gridwork or frame underwater. This is extremely labor intensive, and can take more time and effort than the final product warrants. On the other end of the spectrum, one can swim over a site, shoot tons of overlapping images and somebody skilled at Photoshop can create a stunning visual image – in all likelihood, however, it won’t be extremely accurate and shouldn’t be used as a substitute for an archeological map. This type of image can still have great interpretive, educational and management value, however. We’re striving for something in-between – a methodology that is fairly quick, but gives us some controls. We’re not trying to replace the hand-drawn map, we just want the stunning image to augment it. To strike this balance, we’re going to experiment with several different techniques. The first is to use 2 ft. 6 in. by 3 ft. 6 in. PVC frame and leapfrog it while placing brightly painted weights at each leg. Our photographer, Brett Seymour, then shoots a single image per frame; later he’ll use Photoshop to remove lens-distortion and stitch each image into an overall mosaic. From the photographer’s point of view, this is like seeing a 608 ft. battleship one small, 2 ft. by 3 ft. rectangle at a time. For the viewer after the mosaic is complete, hopefully it will be like floating over Arizona with all the water miraculously removed.

Dave Conlin (left) and Matt Russell retrieve an oil sample from our collection tent. Photo by Brett Seymour, NPS.

Our other task of the day was to collect a series of water, oil, sediment and concretion samples for Dr. Ralph Mitchell and Dr. Chris McNamara at Harvard University. Ralph and Chris are creating experiments to determine how microbial-induced corrosion (bugs that eat steel or whose metabolic byproducts corrode steel) affects Arizona’s hull, particularly its oil bunkers. We also started measuring the rate that oil is leaking from the ship at various locations, which we’ve been doing periodically as part of a long-term monitoring project. Jeff Woods, from the Memorial dive team, and I set-up a custom-built oil collection device (OCD) – made by our good friend Kim Johns at USIA, a drysuit manufacturer (among many other things) – over an oil leak-point, then capture the oil for a 24 hour period. We’ll shift the OCD around to a different site each day, and at the end we’ll have a good idea how much oil is leaking from Arizona each day. In the past its varied between 1-2 quarts per day. We’ll see where it is now. . . .

SRC divers (l. to r.) Brett Seymour, Dave Conlin and Matt Russell. Photo by Art Ireland, NPS.