Whether the men could be rescued before their oxygen ran out depended on an unproved diving bell, the seamanship of the crews, courageous divers, a quick-thinking admiral, a visionary submarine commander and the vagaries of New England weather.
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Since 1921, 825 men had died in submarine accidents. No rescue attempt had ever succeeded. In 1925, Momsen commanded a submarine that made a futile attempt to rescue a sister sub rammed by a passenger ship. The officers aboard the doomed submarine were his friends.
The environmental conditions in the upper James River include both positive and negative aspects affecting field investigations. Generally poor visibility (the best during this survey being approximately two feet) makes data recording difficult. Visibility is zero in water deeper than 25 feet as there is little or no light penetration; however, visibility can be restored to two feet with the use of underwater lights. Maximum current velocities are approximately 1.5 knots which is just strong enough to carry away silt that divers stir up while working.
Another search method employed was to establish probable wreck locations based solely on the 1881 Maillefert map. By calculating transit angles from shore to the various sites on the nineteenth century map, we were able to transfer these data into transit bearings from our AB baseline. Buoys dropped on these areas served as focal points for visual inspection and probing by divers.
The Northampton anomaly, which also corresponds to the 1881 Maillefert map, has a magnetic intensity of 90 gammas with the gradiometer sensor being 15 feet to 20 feet from the target. The Northampton magnetic anomaly, unlike the Fredericksburg and Virginia anomalies, is a narrow single pole target with associated scatter which suggests a concentrated area of scattered iron debris (Fig. 8). Upon examination of this target, divers encountered scattered wood, 11-inch to 2-inch iron piping, rock, copper sheathing, and many iron mechanical-type objects some of which were recovered for on-site photographs and subsequently re-deposited on the site. 2ff7e9595c
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