I spent most of my career in the sonar business. It was always assumed that sonar can only work when both the transmitter and the receiver were in the same body of water; air to water sonar was not possible because sonar can not break the air-water interface. Sure, there were planes that could “dip” a device into the water that would transmit and receive sonar signals, but that is still considered a water-water sonar. Thanks to the innovative minds of Stanford University, there may now be a way to transmit and receive sonar from an airborne platform. Who would have thought?
Stanford engineers explain that the Photoacoustic Airborne Sonar System, or PASS, fires a laser into the surface of the water, its intensity pulsed to the desired acoustic frequency, and as this laser energy is absorbed, it creates ultrasonic waves in the water that can act as effective sonar waves, bouncing off underwater objects before returning up to the surface. “If we can use light in the air, where light travels well, and sound in the water, where sound travels well, we can get the best of both worlds”
This can be a game changer for Anti Submarine Warfare. Aircraft would be able to search for submarines without dropping sensors into the water. This would be advantageous because aircraft could search an area more quickly, and the splashing sound of the sensors would not give away the presence of the aircraft.
If sonar interests you, or if you work with sonar, consider taking the upcoming ATI course “Sonar Principles and ASW Analysis.” This three-day course provides an excellent introduction to underwater sound and highlights how sonar principles are employed in ASW analyses. The course provides a solid understanding of the sonar equation and discusses in-depth propagation loss, target strength, reverberation, arrays, array gain, and detection of signals.
To learn more about this course, and to register, you can go here.
And, to learn more about other courses offered by ATI, please go to www.aticourses.com
SUBMARINE TASKING. Pursuant to mission accomplishment in support of national policies, and in particular for a duly delineated national armed-force objective to “Project National Power,” submarines can be tasked to launch land-attack cruise-missiles from international waters– as directed unilaterally by our National Command Authority, NCA.
Submarines can be tasked to conduct surveillance and reconnaissance operations inside and outside the battle space, covertly. In that same vein, submarines can be tasked to insert, and, or retract Special Operating Forces, SOF, on the littoral shores of the world’s oceans– covertly.
In more poignant warfare scenarios, submarines can be tasked to mine sea-lane choke points as well as enemy harbors.
Moreover, and perhaps most particular, submarines can hunt and kill other opposing submarines in the same undersea medium with them. Besides the deep ocean, that undersea medium includes the shallow waters for our coastal defense as well as that for projecting US national power by amphibious forces in foreign waters.
Notwithstanding the brassy jingoism above, submarines were first procured to sink threatening warships by surprising them from below the sea with the numbing sting of a torpedo. For over a hundred years now, submarines have been so tasked; and, since WWI, submarines have been tasked to interdict sea lanes and sink unarmed merchant ships to deny re-supply. Yes, VIRGINIA, an economic strangler lurks in the sea— Submarines Sink Ships!
When SEAWOLF— conceptualized in the painting above—was launched in 1995, there were some 24,000 merchant ships of over 1,000 gross-registered-tons plying the sea lanes of the world for international trade and transport. For national comparison, a table of Merchant Fleets of the World, ranked by number of oceangoing vessels, is provided below delineating a grand total of their displacements as about 657-million dwt (deadweight tons).
As capital-intensive assets—meaning their annual amortized construction cost and operating expense well exceed the cost of labor to operate them—their collective loan-value, without any consigned cargo, can be estimated parametrically to total about $1.5-trillion. Moreover, the annualized value of their consigned cargo that they deliver each year can be estimated to total about $3.0-trillion.
Ask yourself which of these national economies today could stay afloat with the sunk cost of its Merchant Fleet?
And today, with near instantaneous news around the world, when the first explosion from a submarine-launched torpedo plumes brusquely, so will ocean-shipping insurance rates.
In regard to fleet operations, submarines can be tasked to provide INDIRECT, ASSOCIATED, and DIRECT Battle Group support. For deployments, Time-On-Station for modern nuclear-powered submarines is dependent only on the amount of food they must carry to feed their crew—like, a 90-day supply, without replenishment.
Some submarine-patrol stations literally are On the Far Side. For instance, our forward submarine base on Guam in the western Pacific is about 12 days of submerged steaming from San Diego. Then for a submerged transit from Guam to a patrol station in the Gulf of Oman via the Java Sea and the Lombok Straits thence across the Indian Ocean could take as long as 16 days.
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