News | Oct 5, 2017

7 Navy inventions patented during World War II

High-value partnerships between the Department of Defense and private industry led to the development, transfer, and transition of leading-edge technologies

News Article Image of 7 Navy inventions patented during World War II

By Artist Jon Whitcomb for the U.S. Navy in 1944.

World War II was a time of incredible innovation for the U.S. Navy, particularly for the submarine fleet, which transformed from coastal defenders into larger, long-range patrols with help from the academic community and private industry.

TechLink, the Department of Defense’s national partnership intermediary, supports that American tradition of collaboration, helping businesses access technology developed in Navy laboratories.

In times of peace and war, the military relies on partnerships with industry to address capability gaps and supply American forces with the technology that allows them to be operationally capable across the full spectrum of environments.

These partnerships also strengthen the national economy by allowing businesses to grow using technologies developed by the military to create new products and services with civilian and defense applications.

Here’s just a few of the cutting-edge technologies patented by the Navy during World War II that allowed it to be a decisive seapower in two oceans.

Echo Ranging System (FM Sonar) – U.S. Patent 2,724,817

Submarine USS Gato (SS212), off Mare Island Navy Yard, November 29, 1944. (Navy photo via U.S. Naval Historical Center)

During WWII naval engineers were hard at work detecting the deadly German U-boats that paralyzed merchant commerce in the Atlantic. Echo ranging systems detected U-boats with a series of pings that would echo back providing a distance and direction. To scan a 180 degree arc of water out to 5,000 yards using 5 degree increments, it took four minutes of pinging–sound waves in ocean water travel at a substantially constant rate of about 1,600 yards per second.

This was considered too slow. And the pings could suffer from other interferences like turbid water, which resulted in difficulty tracking targets or missing them altogether.

Enter Hollywood sound engineer Charles Hisserich. Under a Navy contract at the recently founded University of California-San Diego’s Division of War Research, Hisserich outlined the FAMPAS technology, frequency modulated, pulsed active sonar, shortened to FM Sonar. This cutting-edge innovation allowed the Navy to track multiple targets with a single ping. The Navy registered it with the patent office in 1943.

Printing and coding machine – U.S. Patent 4,155,659

Illustration of the Navy's printing and coding machine

Illustration of the Navy’s printing and coding machine patented in 1940. (Troy Carter/TechLink)

Keeping the Axis forces from intercepting communications wasn’t easy, but it was very important. The military prepared for such interceptions by using a ciphertext. At the time, the Army and Navy were using the Teletype Corp.’s ECM Mark II (also known in the Navy as CSP-888/889 or SIGABA by the Army) to produce ciphertext. It allowed the accurate production of ciphertext messages and the deciphering of those received.

Three inventors, Edward S. Larson, Carl A. Levin, and Rolf A. Thienemann, employees of TeleType, made an improvement on this spectacular piece of equipment for the Navy during World War II. The Navy patent application was filed on February 5, 1940. “We are aware that heretofore machines of this general type have been proposed and constructed, but they have certain defects that render them not perfectly accurate and dependable under all conditions. The present invention contemplates and provides safeguards whereby the defects in the previous mechanism are overcome,” the patent reads.

Induction Ground Mine and Firing Mechanism – U.S. Patent 4,183,301

illustration of U.S. Patent 4,183,301

Color enhanced illustration of U.S. Patent 4,183,301 (Troy Carter/TechLink)

Submarines are so large that they have their own magnetic field. This fact allowed the Navy to develop underwater mines that would explode when a searching induction coil sensed the change in the magnetic field. This invention improved on the magnetic mine design with a vertical induction coil and a drag chute that allowed the coil to stay vertical after being dropped by a surface ship. It was registered by the Navy with the U.S. Patent & Trade Office in 1944.

Improved Hydrophone Casing – U.S. Patent 2,641,751

Patent illustration of the Navy’s hydrophone invention. (Troy Carter/TechLink)

The Navy uses hydrophones as their underwater microphones, then listening for German U-boat activity during World War II. This novel hydrophone, when deployed, hangs below a floating buoy in a listening position. Prior to being dropped in the water, the hydrophone and its suspension cable are packed into the bottom compartment of the buoy.

When the buoy is dropped by parachute and lands in the water an impact operated spring-release mechanism allows the hydrophone to drop out of the bottom of the buoy and hang by the suspension cable.

This novel hydrophone design allowed a compact storage of the suspension cable in a way that prevented it from kinking, the patent reads. The Navy registered the design with the patent office on May 11, 1944.

Apparatus for firing an underwater depth charge – U.S. Patent 3,511,182

Patent illustration of the Navy's improved depth charge fuse

Patent illustration of the Navy’s improved depth charge fuse. (Troy Carter/TechLink)

This device improved the Navy’s chances of scoring a hit with a depth charge, a type of bomb dropped by surface ships in hopes of destroying enemy submarines.  “In naval warfare, the problem of destroying submarines after they have been located is an exceedingly important one,” the patent reads.

The inventor, Frank A. Hestor, Jr., said his invention detonated the depth charge only when it was close enough to damage the enemy submarine using a “magnetostriction loudspeaker-microphone oscillator unit provided with a vibratory diaphragm and a three-quarter wavelength magnetostriction rod.” It also prevented other depth charges from premature detonation caused by the shock of other charges exploding nearby.

Bathythermograph – U.S. Patent 2,515,034

Illustration of the Navy's patented bathythermograph.

Enhanced illustration of the Navy’s patented bathythermograph. (Troy Carter/TechLink)

The Navy filed for a patent in 1944 on an improved bathythermograph invented by William M. Ewing and Allyn C. Vine of the Woods Hole Oceanographic Institution.

A bathythermograph is a small torpedo-shaped device that holds a temperature sensor and a transducer to detect changes in water temperature versus depth down to approximately 900 feet. The device is typically lowered by a small winch on the ship into the water, and the temperature changes are recorded on a coated glass slide. Bathythermograph data is of special interest to submarine operators because water temperature can vary at different depths and cause inaccurate sonar location results. By mounting a bathythermograph to his submarine and monitoring its data, a sub commander could more accurately fire torpedoes.

“It is an object of this invention to provide a bathythermograph having a high speed of thermal response whereby it may be lowered and raised swiftly from a moving vessel while still making an accurate record of the water temperature encountered at various depths, rapidity of lowering being a prerequisite for reading the desired maximum depth when operating from a rapidly moving vessel,” the patent states.

Crystal and method of fabricating same – U.S. Patent 2,489,393

Illustration of the vise for producing larger crystals that was patented by the Navy in 1944.

Illustration of the vise for producing larger crystals that was patented by the Navy in 1944. (Troy Carter/TechLink)

Like Hisserich above, T. Finley Burke and George A. Argabrite were contributing to national defense via the University of California-San Diego’s Division of War Research. While there, Burke and Argabrite tackled a number of technological issues, one of which was the construction of large crystals needed for transducers that could produce low frequency sonar signals.

“The industry has found many uses for large size crystals which, because of the usually complex method of growing, are difficult to produce. As the necessary size of the crystals increases, the percentage of usable and flawless structures produced becomes less. These difficulties have been found to be particularly important in the production of piezoelectric crystals used in radio and sound transmission and reception. Since the operating frequencies of the crystals used in such work is a direct function of size, it is obvious that for low-frequency operation, large size crystals are necessary. Even if grown by the usual methods in temperature-controlled baths, which is not at all feasible for some types of crystals in any case, the process is still both expensive and time consuming,” the inventors wrote in the patent.

Others had already taken two smaller crystals and glued them together, but the glue would fail. So instead of using glue, Argabrite and Burke heated the smaller crystals until they melted, then simply pushed them together.

“It not only appears that the lattice structure suffers only slight discontinuity at the joint but also that the joint is such that no new substantial losses are introduced,” they reported.

Interested in learning about technologies more recently developed by the military? Search TechLink’s database of over 5,000 technologies, which are available to businesses who would turn them into new products.

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