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Assessment of marine life attack and damage on submarine cables and towed arrays is conducted in our lab and during field tests with live sharks and bony fishes. Previous work on nuclear submarine towed acoustic arrays determined likely candidate organisms biting the arrays from tooth patterns and analyzed the distribution of bites to determine if the damage was random or clumped near particular electronic parts or couplers. Gross and scanning electron microscopic analysis of damaged cables and hose was compared to a library of hoses attached by known candidate organisms to narrow the search for candidate predators. Known bite forces from sharks were also used to conduct material testing of fish teeth to asses the ability of sharks to puncture pressurized submarine arrays. Force and work to penetration of teeth puncturing hoses is also ascertained by a Material Testing System (MTS). Field testing with live sharks and bony fishes was also conducted in Bimini, Bahamas, allowing us to determine actual damage inflicted on these marine predators and the ability of Kevlar fibers to resist attack. Contracts or grants to assess marine life attack damage or resistance can be arranged through Dr. Motta’s lab and the University of South Florida.    

Oil rig towed array

Shark bites on the towed array cables

Investigating how shark teeth cut through rope...
     
Submarine showing housing for towed array on its upper deck. The towed array which is deployed from the housing may sustain damage due to marine life attack.

Tooth puncture analysis of submarine towed array hose indicates approximate size and type of marine life attack on the components.

Bite marks on submarine towed array indicating multiple punctures from adjacent teeth.
     

Material testing of force to puncture on TB-29 submarine towed array hose to determine how much force is necessary for sharks to damage the towed array.

Material testing force to puncture of a shark tooth on TB-16 submarine towed array hose.

Scanning microscope analysis of TB-23 hose fibers cut by a fish tooth (top). Fiber damage is compared to damage inflicted by tensile tests and fibers cut with man made cutting tools (bottom).
     
Dr. Motta tests the bite resistance properties of Kevlar fabric by offering it to Caribbean reef sharks in Bimini
Testing bite damage capacity on the Kevlar-wrapped arrays with Caribbean reef sharks at the Bimini Biological Station

Results of the Kevlar testing, showing damage inflicted by Caribbean reef sharks.

     
Dr. Motta examines teeth from a deep water bony fish suspected of attacking submarine towed arrays.
Caribbean reef shark biting a section of TB-29 submarine towed array to ascertain extent of damage and tooth bite profile.
All photos are © Philip J. Motta