Excavating the Defence
by David C. Switzer

From June 1 to July 15, 1975, the major task was to conduct a feasibility study of the Defence site to ascertain whether or not a complete excavation should be scheduled for the summer of 1976.  In addition to myself, Dr.  George Bass, and associate project director David Wyman, the Defence project team included eight students and two "old-timers" Mary Strouse and Faith Hentschel. The student group included a wide range of talents.

Much time was devoted to constructing equipment designed to facilitate working in the shallow but cold and murky waters of Stockton Harbor: a clear water box was made to aid underwater photography; a floating sieve was required for the discharge end of the airlift; a grid of 2" PVC pipe provided points of reference on the sea bed. By the end of the first week, which included orientation dives, a 50' by 20' float provided by the Maine Maritime Academy was towed to the site by the expedition boat Panthalass, and anchored over the wreck.

Once diving began in earnest, we operated in teams of two in designated sectors of the wreck in order to provide information concerning the condition of the vessel.  Excavation was conducted outside the bow, at the stern, and in the fore peak.  The port side frames, the best preserved, were cleared and numbered. A trench was extended from the port side forward of the main mast to the center line. Extensive airlifting was also carried out in the stern area.  Here was revealed a jumble of timbers most likely caused by an explosion of the magazine at the time of the scuttling.

Underwater work was extremely difficult: visibility ranged from zero to six feet.  When the airlift was operating, the former figure prevailed.  The students, however, got the feel of things very quickly.  Aiding in this respect were classes in ship construction conducted by AINA (now INA, ed.) ship reconstructor J. Richard Steffy.  On a trip to the Penobscot Marine Museum, Dick was able to expand on his classroom talks, aided by numerous models, pictures, and pieces of equipment on display.

In addition to a number of inboard profiles that were obtained through probing, all of the port side frames and a majority of those on the starboard side were triangulated. Using these figures, David Wyman drew up an extremely accurate site plan-working in the little shack on the float that served as a work area and a warming hut on foggy, chilly days.

Underwater photography posed a problem.  The clear water box leaked, with the result that seawater quickly displaced clear water. We believe the box still has definite possibilities, and modifications should solve the leakage problem.  Lack of good photographs did not, however, mean that we were not able to obtain pictures of structural remains and objects in situ.  Architect Peter Hentschel became the eyes of the expedition.  On innumerable dives with clipboard, measuring stick, and tape, Peter made preliminary drawings of the bow section, the framing details, and the cookstove and its copper cauldron-one of the outstanding features of the wreck.  From sketches and measurements, he produced excellent diagrams and pictures.  Indeed, as someone commented, "He saw more than any of us."  When he wasn't diving, Peter offered to draw some of the more significant artifacts recovered. 

Artifact conservation was the responsibility of Rhys Townsend and Cynthia Orr, who painstakingly labeled, numbered, recorded, and stored artifacts in a holding tank at MMA.  Formulae and chemicals provided by Maine State Museum Conservator, Stephen Brooke, were employed to retain ferrous and wooden objects in a holding condition.

Although artifact recovery was not the prime concern of the summer's work, a number of objects were brought up by the airlift-grapeshot concretions, cannonballs, wooden grapeshot stands, beef bones, and numerous pieces of wood. One of the most interesting objects recovered was a bone whistle which may have been a bos'n's pipe.

During the limited time we had to work, we were able to experiment with other special equipment designed to counteract the murky conditions created by the silt bottom and stirred-up blue clay which surrounded and filled the wreck over the years. George Bass designed a jet-box, which would allow a diver to maintain visual contact with a small area of the wreck. A square windshield with water jets creating a silt-clearing current, the jet-box could be handled by one person and moved with ease. Some difficulty was encountered, due to the fact that the water forced through the jets was aerated. Again, this experiment proved useful in terms of future equipment design. Another experiment was with a conical polyurethane tent dubbed the Visual Acuity Tent (VAT).  Designed by Peter Hentschel, the tent, with an eight-foot diameter base, will provide one or two divers with a constantly-cleared working area. The clearing current will be provided by a pump on the surface which continually circulates clear water to the apex of the cone.

The Defence excavation project was extremely successful.  The structural remains of the vessel appear to be intact, and we have hopes of beginning a full-scale investigation next summer. I must comment on other elements than those noted above that made things go so well.  One was the enthusiasm of the students. Another was the living and working facilities provided by Maine Maritime Academy.  Also instrumental to the success of the Defence project was the assistance of Warren Riess, who secured a large compressor and provided advice regarding underwater photography.  We all look forward to the summer of 1976 and foresee another successful season built on the foundations of the past summer's experience.

-David C. Switzer

Designed by Ralph K. Pedersen, Jan. 2003.

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