Accession Number:

ADA409150

Title:

Marine Attack on Towed Hydrophone Arrays

Descriptive Note:

Final rept. 15 May 2000-28 Feb 2002

Corporate Author:

SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA

Personal Author(s):

Report Date:

2002-02-01

Pagination or Media Count:

3.0

Abstract:

The original objective of the SIO Marine Attack project was to identify the electric and magnetic fields causing sharks to inflict serious damage upon the towed hydrophone arrays of US Navy submarines. In contrast to the geophysical arrays that we studied concurrently, the US Navys arrays appeared to be electromagnetically very quiet by proper design. The only galvanic fields we measured were those of some set screws of a dissimilar metal than the seawater-exposed titanium parts and those of the titanium parts themselves, especially when scratched or abrades during employment. Those fields will evoke bites from sharks coming close to their sources, as we proved in behavioral experiments. Much more serious fields are the image fields of the arrays in the electric fields due to oceanic and ionospheric circulations. As the latter fields can not be removed, we have added to the original project the innovative objective of designing weak counter fields to divert or utterly confuse sharks coming near the arrays. Further studies in our Electromagnetic Research Facility and tests at sea to determine the efficacy of the counter fields are in progress.

Subject Categories:

  • Electrical and Electronic Equipment
  • Defense Systems
  • Electricity and Magnetism
  • Biology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE