SBIR-STTR Award

The proposed project will create an innovative Trawl Resistant Tether System to protect vertically suspended, bottom-tethered types of ocean bottom sensor installations from the vulnerabilities of trawl rig damage. It uses innovative geometry and fabrication techniques that do not impact the sensor performance in any way. The proposed system addresses two specific vulnerabilities: damage to the top of the tethered float and sensor assembly caused by contact with the trawl rig leading edge or door, and damage to the tether cable as it exits the truncated pyramid trawl resistant bottom mount base. To resist damage to the tethered float and sensor assembly, the solution incorporates a protective shield that prevents it from snagging in the trawl rigging at the point of transition between the tether and the float and sensor. To eliminate the risk of damage to the tether cable as it exits the base, a pinch- and shear-proof surround at the attachment point is incorporated and prevents the tether cable from being pinched or severed by the leading edge of the trawl rig or the bottom edge of the steel door. The proposed solution for feasibility study offers sensor protection not currently addressed by trawl resistant bottom mount products.

Benefit:
The proposed solution for feasibility study offers sensor protection not currently addressed by trawl resistant bottom mount products. The innovative solution protects vertically suspended, bottom-tethered types of ocean bottoms sensor installations from two forms of trawl rig damage (to the top of the tethered float and sensor assembly and to the tether cable) through innovative geometry and fabrication techniques that do not impact sensor performance in any way. The benefits extend beyond the anticipated initial Navy use. Identified applications include significant market opportunity for the environmental industry, oil and gas drilling efforts, and scientific bottom-mounted installations.

Keywords:
tether, tether, Sensor, subsurface float, subsurface sensor, Trawl Resistant, trawl, Bottom Mount

The ocean bottom is a protective location for sensors, unless a trawl fishing rig drags over the sensor. Because a trawl fishing rig scrapes the ocean floor and scoops fish into a net, it can be devastating to bottom mounted sensors, especially when sensors are vertically tethered in the water column with sub-surface floats. The upward reaching appendages in a typical Navy testing range are easy prey against the trawl rigs heavy chains and rock hopper leading edges, which snag the sensors and damage or rip them from their tethers. This program has developed passive, innovative methods of protecting the typical tethered sensor from becoming entangled in or damaged by a direct trawl rig strike. Specifically, this effort is targeted for the protection of arrays in planned shallow water Navy undersea training ranges. Because the unique SkySight Deployable Trawl Safe system is compact enough to be deployed through a modified linear cable engine, the time and cost to incorporate the needed hazard protection is reduced when installing large undersea arrays. The successful Phase I used scale models and rigorous test analysis. The Phase II effort will build on this success and result in an ocean-demonstrated sensor protection system.

Benefit:
The immediate market for the proposed trawl survivability system will be a future undersea warfare training range. This range will likely be the first one planned to be operated in littoral waters where commercial and sport fishing are a threat to the integrity of the array. Other test assets susceptible to trawl rig damage are also candidates for the type of protection being developed under this task. SkySight Technologies is exploring commercial applications of the SkySight Deployable Trawl Safe configuration. These applications include virtually all moored ocean sensors and systems. Potential applications include channel markers, crab pot markers, and undersea environmental sensors. There are also consumer appliance and power tool applications for which the unique features developed under this effort can be incorporated to prevent cord snags when the item is being pulled over a step or ledge.

Keywords:
ocean bottom array, trawl, SkySight, trawl fishing, survivable, USWTR, testing range, subsurface float