Two
recent tragedies, the loss of TWA Flight 800 and the loss of
the private aircraft piloted by John F. Kennedy, Jr., have high-lighted
the role of NOAA's National Ocean Service Office of Coast Survey
in locating objects on the seafloor. This skill has evolved
as the result of 165 years of experience in nautical surveying
beginning with charting surveys in 1834.
In the early 1900's the Coast and Geodetic
Survey began experimenting with a method of discovering seafloor
obstructions called wire drag. This system involved stringing
a continuous wire between two vessels that would then steam
slowly ahead while being carefully navigated by three-point
horizontal sextant fixes. The wire would be held at a set depth
by a system of weights and buoys. If an object was encountered
or "hung" by the wire, it would become apparent by both vibrations
in the wire and by a V-shaped pattern as seen in the surface
buoys. The first of the articles below is a special report written
in early 1933 by Captain Nicholas Heck of the U.S. Coast and
Geodetic Survey and recounts the use of wire drag to discover
the remains of a private aircraft lost at sea. This was perhaps
the first time that the remains of an aircraft that had sunk
immediately after impact was found as the result of an intentional
search. As such, Captain Heck's report is a landmark in the
history of marine exploration and salvage.
The second article included in this section was written by Dane
Konop, editor of the NOAA Report, and recounts
the efforts of the NOAA Ships RUDE and WHITING to discover the
remains of the aircraft piloted by John F. Kennedy, Jr. This
article appeared in the August 1999 edition of the NOAA
Report. Search for the remains of this aircraft centered
in Martha's Vineyard, less than 100 miles south of the scene
of the 1933 disaster. Two thirds of a century after the first
tragedy, technology had changed significantly. The last of the
venerable wire drag work had been done by the NOAA Ships RUDE
and HECK in the early 1980's. Sidescan sonar systems that transmit
sound through the water to reflect off of seafloor objects were
then in widespread use and replaced the wiredrag method. The
reflected sound is received by a sensing instrument and generates
seafloor imagery that is analogous to aerial photography, although
interpretation of the images requires human experience and skill.
As opposed to visual three-point sextant fixes, the RUDE and
WHITING were navigated using a Differential Global Positioning
System that allowed them to operate in all levels of visibility
with pin-point accuracy. These differences in technology were
significant. Even if the Kennedy plane had been observed as
it hit the water, it is improbable that it would have ever been
found using the earlier technology because of a very rocky bottom
and also because of the difficulty of using precise visual navigation
far from shore. Although a different part of the effort, radar
technology was a major factor in helping localize the search
for the aircraft. In both cases, the end result was the same.
The lost aircraft was discovered.
