of using the bathyscaph to dive to the bottom of Challenger Deep in the Marianas Trench in 1960 as a part of Project NEKTON. Trieste's historic dive to the bottom of Challenger Deep in 1960 clearly demonstrated that man could penetrate the oceans to even their deepest depths. But the bathyscaph was large and difficult to operate and maintain in the open sea many miles from its home base.
Global coverage required the capability to carry the diving craft aboard a surface support ship that could transit at high speeds to the dive site and between dives bring the craft back aboard for maintenance and repairs. This dream of a tiny portable submersible was, in fact, already beginning to take shape even before Trieste's 1960 diving campaign in the mind of a young French officer, Jacques Cousteau, who had witnessed the first test dive of the bathyscaph FNRS-2 off Dakar in 1948. Cousteau' s Souscoup was the first modem deep submersible to be built. However, its diving capability was limited to 300 m, far too shallow for the oceanographic community.
Just as Cousteau's experience with the French bathyscaph lead to the creation of the Souscoup, the Americans diving on the Trieste began to think about a similar modem submersible small enough to be carried aboard a mother ship.
No sooner had Trieste completed its deep dive in 1960, than the San Diego group including Andy Rechnitzer, Don Walsh, and Larry Schumaker began to dream of its replacement. Listening to these discussions was Harold "Bud" Froehlich, a General Mills engineer who had built Trieste' s mechanical arm. Soon he was circulating the designs of a small prototype submersible he called the Seapup to anyone who was interested.
While this teapot began to boil, another spark was being lit on the East Coast. Charles B. "Swede" Momsen, Jr., the Chief of Undersea Warfare in ONR, the same organization that had sponsored Trieste, had received a proposal from J. Louis Reynolds of the Reynolds Metals Company to design and build an all-aluminum submersible called the Aluminaut. Momsen was a decorated submarine commander during World War II and was comfortable with its large design. The only problem was that ONR was not in the business of building submarines; it could rent one if Mornsen could find scientists interested in using it. Ironically, when Momsen went to the Scripps Institution of Oceanography in San Diego where Trieste was now based, he received a cold reception to his idea.
This was not the case when he approached scientists at the Woods Hole Oceanographic Institution (WHOI) on Cape Cod, Massachusetts. In particular, Allyn Vine and WHOI Director Dr. Paul Fye welcomed the idea and offered Woods Hole as Aluminaut's home base. What followed, however, was a long and drawn out series of discussions between ONR, Woods Hole, and J. Louis Reynolds. The sticking point was the ultimate ownership of the Aluminaut. Reynolds wanted to maintain title, while ONR wanted the Navy to own it with eventual ownership going to Woods Hole.
As time ticked on, the engineers Woods Hole had hired to operate the Aluminaut program began to question its design. They had the same concerns Cousteau had. Aluminaut was to be 51 feet long and carry six people. More importantly, like the bathyscaphs, it had to be towed out to sea and could not be brought aboard its mother ship for maintenance and repairs.
Finally after three years and four months of nonstop negotiations, an impasse was reached, and it became clear to Paul Fye that something new had to be tried. The only problem was that others in Washington were trying to pry loose the funds Swede Momsen had been squirreling away for the project.
Knowing other companies were eager to enter the deep-submersible game, Momsen acted quickly and authorized Woods Hole to request bids to build a submersible for the institution. The specifications that went out were not for a submersible like the Aluminaut but for a much smaller design, strangely similar to Bud Froehlich's Seapup.
Seven companies were sent the request for bid: Froehlich's General Mills, Lockheed, General Dynamic's Electric Boat Division, General Motors, North American Aviation, Philco, and Pratt Whitney Aircraft. Although four of these companies would eventually build their own deep submersibles, only two submitted bids to build what would become Alvin; General Mills and North American Aviation. General Mills was the ultimate winner since the Navy felt it was more committed to the project. Ironically, shortly after winning the bid, General Mills sold its division to Litton Industries, which finally built and delivered Alvin to Woods Hole in the summer of 1964.
Alvin could initially dive to 1,830 m, far deeper than the Souscoup , but clearly not to the abyssal depths of the bathyscaphs. As a result, the early users of Alvin were midwater biologists and scientists working on the continental margin.
Frank Manheim, a geologist with the U.S. Geological Survey at Woods Hole, was eager to extend his research on marine snow that had been pioneered by the Japanese. For years, Manheim had filtered seawater obtained from lowered instruments and weighed the dried filters to determine how much marine snow existed per unit volume of the ocean.
When he repeated this procedure using water collected from Alvin, he realized that this method of quantifying marine snow was not accurate. On his dive, he had seen a heavy snowfall, but the weight of his filters drawn from water collected by Alvin indicated otherwise. In the mud cores he brought up, there was little organic material. This seemed to indicate that the animals were extremely adept at food gathering; they were consuming the fine rain of organic material as soon as it hit bottom.
Studies of the deep scattering layers, also begun by the bathyscaph, continued using Alvin. Woods Hole biologists Richard Backus and Jim Craddock used Alvin and its highly sensitive CTFM sonar to study the layer. With the lights