This reader felt that I overlooked the element of surprise…
Employment of the JetLev R200, in its current state of development, requires that planners have adequate intelligence prior to an operation. For example, many harbors and particularly those used by military vessels have acoustic sensing devices that can detect a swimmer or swimmers in the water as well as vessels surfaced or submerged. The JetLev R200 has a significant acoustic signature: pumps, water flowing through the hose, water flow from the jets, the impact of water exiting the jets. Even in areas where there is a considerable amount of biologics it is easily detectable through SONAR and other acoustic devices.
Thanks for your thoughtful question!
FOG HORN 