Evo of Tech: Harold Froehlich invents Alvin deep sea submersible while working at General Mills labs

Harold Froehlich. From the National Inventors Hall of Fame website.

The waters of Planet Earth continue to be the source of great interest from the scientific world; we have better maps of the surface of Mars than we do of the surface of the ocean. Ocean waters cover approximately 70 percent of the Earth’s surface but 95 percent of the underwater world has never been seen by human eyes. As of October 2014, the best map of the world’s ocean floor had a maximum resolution of about five kilometers, so researchers can only see features which are larger than five kilometers across. As this article on the importance of ocean exploration published online by the National Oceanic & Atmospheric Administration points out, greater knowledge and understanding of the world’s ocean floor can provide researchers with better baseline information for understanding environmental change, aiding in forecasts for earthquakes or tsunamis. Better understanding of underwater ecosystems can also render potential new sources for various products like food, medicines or energy resources.

Interestingly enough, the world of deep sea exploration actually owes a great deal of gratitude to a major American cereal company for providing a major advance in submersible vehicle technology. Sunday, September 24th, marked the 54th anniversary of the issue of patent covering an underseas vehicle technology issued to Harold Froehlich, then an engineer at General Mills. This May, Froehlich was included among the inductees of the National Inventors Hall of Fame’s 2017 class for his work in developing the deep sea human occupied vehicle Alvin.


So How Does a Cereal Company Become the Hotbed of Deep Sea Research?

Harold “Bud” Froehlich was born in July 1922 in Minneapolis, MN. He pursued an education in aeronautical and mechanical engineering and would earn his bachelor’s degree from the University of Washington and then complete his master’s education at the University of Illinois at Urbana-Champaign. Froehlich also gained an early knowledge of waterborne vessels having served with the U.S. Navy as a signalman during World War II before he began his collegiate studies.

After receiving his master’s degree, Froehlich worked as an aircraft engineer for the Boeing Company and a few other aeronautics firm before moving over to General Mills during the 1950s. Despite the common perception that General Mills is primarily a company that makes breakfast cereal, the firm has a history of research and development which has developed innovations like puffing guns for puffed cereals, a machine for packaging loose tea and other foodstuffs, as well as innovations like Alvin which aren’t meant to be covered with milk and consumed via spoon.

During his time at General Mills, Froehlich worked in a General Mills lab which was focused on aeronautics research used to develop precision military equipment; he was mainly involved with the developmen

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t of high-altitude balloon equipment used to study the Russian nuclear program by collecting air samples at altitudes of up to 100,000 feet. He helped with the development of a mechanical arm technology which caught the attention of the Navy Electronics Laboratory (NEL) at the U.S. Naval Institute and Woods Hole Oceanographic Institute.

Froehlich also gained a good deal of experience in mechanical engineering for underwater environments at the General Mills labs. The Navy contracted with General Mills to develop breathing systems and helium gas valves for balloons and Froehlich worked on many of these contracts. He also helped to design a mechanical arm technology for the bathyscaphe Trieste which helped the craft descend 35,000 feet into the ocean.

Developing the Alvin to Survey the Deepest Floors of the Oceans

Even though the General Mills labs was located 1,000 miles away from the ocean, the company beat out major military contractors like Lockheed and North American Aviation to earn a contract in the early 1960s for building a self-propelled, two-man deep sea vessel which addressed the shortcomings of conventional underwater vehicle technologies of the time. Most self-propelled submersibles had mechanical issues which prevented them from being used in deep sea environments. Bathyscaphes could reach depths of tens of thousands of feet but were very heavy and thus had low maneuverability.

Thus, the deep sea submersible developed by Froehlich had to overcome both structural and weight issues. To keep the craft at a low weight, Froehlich employed a new kind of material called syntactic foam, a type of polymer material in which a metal or ceramic matrix is filled with hollow microballoon spheres to create a buoyant, low-density, high-strength material; the microballoons of Froehlich’s syntactic foam were composed of aluminum. The submersible incorporated Plexiglass for windows and had a mechanical arm, a detachable steel cockpit and propulsion units for forward, horizontal and vertical movement. Landing skids were added to keep the craft stable when it reached the ocean floor and ballast was added to improve the craft’s underwater stability.

On September 24th, 1963, Froehlich and General Mills were issued U.S. Patent No. 3104641, titled Underseas Vehicle. It claimed an underwater vehicle comprising a hull having a bow and a stern, a means mounted at the stern for stabilizing and maneuvering the vehicle, a means mounted within the hull for moving the stabilizing means to maneuver the vehicle, a first propulsion unit mounted within and movable with the stabilizing means, at least a pair of rotatable propulsion units, means for mounting each of the pair of rotatable units on the hull near the bow. The mounting means for the rotatable propulsion units included motor and gear assemblies for rotating each of those units for 360 degrees about an axis transverse to the longitudinal access of the vehicle, changing the direction of thrust of the propulsion units to maneuver the vehicle.

Alvin, operated by the Woods Hole Oceanographic Institution, took its first dive in 1964 and over the course of decades it accomplished some astonishing things. While the Cold War raged between the U.S. and the U.S.S.R. in 1966, Alvin was used to find an abandoned hydrogen bomb in the Mediterranean Sea off the coast of Spain. In the 1970s, it explored the first known hydrothermal vent. In 1986, Alvin gave the world its first views of the Titanic more than 70 years after that cruise liner sank in the Atlantic Ocean. In 2010, Alvin was used to survey subsurface damage after the Deepwater Horizon explosion and oil spill. Alvin continues to be upgraded and is currently nearing a depth rating of 6,500 meters, which would give the craft access to 98 percent of the world’s seafloor.

For Froehlich’s part, he would go on to join 3M as an engineer and worked on technologies like oil burners for navigation buoy power and medical equipment like a surgical stapler. Froehlich passed in 2007 but he is named as an inventor on 17 patents. In 2011, he was inducted into the Minnesota Inventors Hall of Fame.


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