TECHNOLOGY AREA(S): Ground/Sea Vehicles

ACQUISITION PROGRAM: Low Observable, No Collateral Damage (LO/NCD) Neutralization FNC

OBJECTIVE: Develop a “plug and play” inspection-class Remotely Operated Vehicle (ROV) compatible non-intrusive means to attach specialized Explosive Ordnance Disposal (EOD) tools to underwater threat objects to enable standoff neutralization of targets on the seabed and in the water column.

DESCRIPTION: The Navy needs the ability to non-intrusively attach specialized Explosive Ordnance Disposal (EOD) tools delivered by an inspection-class Remotely Operated Vehicle (ROV) to neutralize or dispose of underwater threat objects including naval mines and underwater improvised explosive devices (IEDs) from a standoff location. Solutions will be designed to integrate with the Teledyne SeaBotix vLBV300 and the Next Generation EOD Underwater Response Vehicle. Employment procedure must not require specialized skills for human command and control beyond those required for the employment of the associated EOD tool.

The ocean is one of the most challenging environments for underwater attachment using adhesion and/or other mechanical means. While mechanical means provide extremely strong bonds, many cases arise where neither welding nor mechanical fasteners are practical. For example, welding and joining require long application times, are noisy, create vibrations, and generally require the work of a skilled diver. In the case of adhesives, water prevents good mating of the adhesive with the object surface, it diffuses along the interface to assist crack growth, it softens the adhesive, and it hydrolytically degrades the adhesive over time. Perhaps more challenging is the presence of biofouling. Plant and animal matter on the surface prevents contact between the adhesive and the underlying object surface. In cases where the adhesive bonds with the biofilm itself, the poor mechanical integrity of the biofilm leads to detachment at small mechanical loads. Subject tools are neutrally buoyant in seawater and emplaced on a threat object using ROV manipulators.

Underwater adhesives promise the simplicity of placing two surfaces in contact. The process can be performed quietly and without requiring permanent modification of the target vessel. Though commercial adhesives exist, most suffer from two major limitations: application/curing speed and resistance to biofouling. Two-part adhesives are most common. The polymerization initiates when two polymeric precursors are mixed together. The speed of the cure necessarily has to be slow in order to provide enough time for mixing and application. Ultraviolet (UV) curing is a faster option and has the additional advantage of being initiated by UV light after deployment on a surface. However, UV curing can only be used with UV-transparent objects and it also fails on thicker adhesive joints.

The Navy has particular interest in strong underwater adhesives or other non-intrusive attachment systems that can be integrated onto an inspection-class ROV to deliver specialized EOD tools. Potential attachment methods must be able to be adapted to EOD tools without modification and must not increase the influence signature (i.e., noise, magnetic, vibration) of the ROV. The attachment mechanism must be sufficiently robust to ensure a neutrally buoyant tool will remain in place on the target in typical, near-shore ocean current and wave-action surge environments where horizontal water velocities on the seabed can get up to between 10 and 14 meters per second are common.

For adhesive solutions, the desired adhesive should require that the ROV hold the tool in place for 1 minute or less and curing times for final bonding should be in 5 minutes or less, but only after it is deployed on a surface. It should work on all surface types including glass reinforced plastic, aluminum, steel, fiberglass, varying degrees of underwater biofouling (e.g. coral, algae, etc.), and in water temperatures from 32° – 100° Fahrenheit. For bio-materials, the adhesive should either penetrate through the biofilm to the underlying substrate or include a built-in cleaning method for purging the biofilm during application. The goal is to formulate an adhesive or other non-intrusive attachment system that is fast, easy to apply, securely holds tools in place for up to 48 hours (~8 tide changes) once attached, and can be employed by an ROV. The development effort shall include an analysis of the feasibility of production, storage, transport, and deployment by the ROV, including articulation of setup time as a field-configurable payload.

PHASE I: Develop a concept for a non-intrusive means to attach specialized EOD tools to underwater threat objects that works on all surface types, including bio-materials, and meets the requirements in the Description. Include in the concepts how the proposed solution would be integrated onto the Teledyne SeaBotix vLBV300 and the Next Generation EOD Underwater Response Vehicle. Demonstrate feasibility through modeling and simulation. Develop a Phase II plan. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver a prototype adhesive or other mechanical attachment system based on the results of Phase I and the Phase II Statement of Work (SOW), and validate it with respect to the requirements stated in the Description. Address integration of the prototype with the Teledyne SeaBotix vLBV300 and the Next Generation EOD Underwater Response Vehicle. Ensure demonstration via anchoring a mock neutralizer or specialized payload to a stationary object. Note: Phase II demonstrations need not be performed offshore but would ideally be performed in tanks containing ocean water to simulate marine conditions to a practical extent, and would include current and wave-action surge conditions or simulated conditions typical of near shore ocean environments.

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to Navy use in the Low Observable, No Collateral Damage (LO/NCD) Neutralization Future Naval Capability (FNC). If successful, rapidly curing underwater adhesives and/or other novel attachment approaches and field configurable systems for application using a small ROV would have immediate commercial applications for underwater repair and construction.

REFERENCES:

1. Shaw, S.J. “Adhesives in demanding applications.” Polymer International, 41, 193-207 (1996). http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0126(199610)41:2%3C193::AID-PI623%3E3.0.CO;2-6/full

2. De Bonis, D. and La Scala, J. “Advanced Fast Curing Adhesives for Adverse Conditions.” Proc. SAMPE 2007 Conference, Baltimore, MD, 3-7 June (2007). https://www.arl.army.mil/www/default.cfm?technical_report=1450

3. Evans, L. V. “Marine Algae and Fouling: A Review, with Particular Reference to Ship- Fouling.” Botanica Marina 24, 167-172 (1981). https://www.degruyter.com/view/j/botm.1981.24.issue-4/botm.1981.24.4.167/botm.1981.24.4.167.xml

4. Walte, J. H. “Nature’s underwater adhesive specialist.” Intl. Journal of Adhesion and Adhesives, 7, 9-14 (1987). https://www.sciencedirect.com/science/article/pii/0143749687900480

5. Tai, R. C. L. and Szklarska-Smialowska, Z. “Effect of fillers on the degradation of automotive epoxy adhesives in aqueous solutions.” Journal of Materials Science, 22, 6205-6210 (1993). https://link.springer.com/article/10.1007/BF00365044

KEYWORDS: Underwater Adhesives; Non-intrusive Attachment; Explosive Ordnance Disposal; EOD; Remotely Operated Vehicle; ROV; Naval Mine Neutralization; Teledyne SeaBotix vLBV300