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Crawling Amphibious Breacher (CRAB)




Develop a submersible autonomous amphibious breaching vehicle capable of proofing assault lanes from the surf zone (<10 feet depth) through the beach zone, reducing explosive and non-explosive obstacles, and clearing craft landing zones.


The CRAB (Crawling Amphibious Breacher) would be a small, inexpensive, (>$100K per system) submersible autonomous vehicle that will operate in concert with other CRABs. They would be capable of being deployed off-shore, from a depth of approximately 40 feet. CRABs would drop from surface craft to the seafloor and maneuver toward the beach, clearing a lane in a formation. As they move toward the shore, they will neutralize buried and proud (i.e., bottom) sea mines along the way. Mines would be neutralized by targeting the fuze types: pressure fuzed mines by rolling over them; magnetic mines by the heavy metal construction of the CRAB, and tilt-rod fuzed mines by driving into the tilt-rod itself. Once the CRABs exit the surf zone, they will continue up the assault lane, neutralizing land mines by targeting the fuze types, as listed above. CRABs would be small enough that their wreckage can be driven over by an Amphibious Combat Vehicle (ACV) or other large assault vehicles. Once the CRABs reach their limit of advance, they would move out of the assault lane and remain there until the breach is complete. As the CRABs move through the lane, they would drop markers (GPS or other) that landing forces can see on a screen to indicate the cleared lane. These markers would be picked up by receivers in the amphibious force vehicle's common operating picture systems and generate a visible path on the driver display. The CRAB will not be designed to neutralize moored or floating sea mines and will operate without prior Intelligence, surveillance and reconnaissance (ISR) targeting information. The Marine Corps would like the CRAB to be capable of reducing submerged man-made obstacles using a clamshell type of arm, like that of an excavator, but realizes this may make each CRAB too expensive. This SBIR topic is looking for an innovative way to also reduce man-made obstacles using the most inexpensive means.

Key Performance Parameters (required) of the CRAB:

  • Error rate of <3 ft.
  • Autonomous underwater operation
  • Operating in depths of <40 ft of saltwater
  • Capable of deployment from surface or subsurface watercraft near shoreline <400m from shore
  • Must be able to self-right or operate in any orientation (if flipped over, can still maneuver or turnover)
  • Must be capable of operating in sand, mud, and shell soil sea floor
  • Must detonate pressure fuzed buried and bottom sea mines (~500lbs PSI)
  • Must detonate pressure fuze buried and surface laid land mines (~500lbs PSI)
  • Overall size must not exceed (LxW) 12'7" x 5'0"
  • Overall weight must not exceed 14,000 lbs

Key System Attributes (desired) of the CRAB:

  • Capable of remote or waypoint operation
  • Capable of using targeting data (potentially IS2OPS) to target identified buried mines
  • Capable of swarming or moving in formation
  • Capable of communication within swarm while underwater
  • Capable of communication to surface craft
  • Mark cleared lane with dropped sensor in water and land (example; dropped RFI pucks along outer edge of breached lane)
  • Battery operated with enough operation time to conduct an eight hour mission
  • Capable of reducing submerged man-made obstacles (pushing hedgehogs, tetrahedrons, cutting concertina wire)
  • Capable of detonating tilt-rod fuzed mines
  • Capable of detonating magnetic influence mines


Develop concepts for a CRAB vehicle that meets the requirements described above. Demonstrate the feasibility of the concepts in meeting Marine Corps needs and establish that the concepts can be developed into a useful product for the Marine Corps. Establish feasibility by material testing and analytical modeling, as appropriate. Provide a Phase II development plan with performance goals and key technical milestones, and that addresses technical risk reduction.


Develop a scaled prototype for evaluation. Determine the prototype's capability in meeting the performance goals defined in the Phase II development plan and the Marine Corps requirements for the single amphibious integrated precision augmented-reality navigation system. Demonstrate system performance through prototype evaluation and modeling or analytical methods over the required range of parameters, including numerous deployment cycles. Use evaluation results to refine the prototype into an initial design that meets Marine Corps requirements. Prepare a Phase III development plan to transition the technology to Marine Corps use.


Support the Marine Corps in transitioning the technology through test and validation to certify and qualify the system for Marine Corps use. Develop a CRAB vehicle for evaluation to determine its effectiveness in an operationally relevant environment. Support the Marine Corps for test and validation to certify and qualify the system for Marine Corps use.

KEYWORDS: Autonomous; Unmanned Underwater Vehicle; UUV; Mine Countermeasures; Swarming; Breaching; Amphibious


1. Daily, William, et al. "Initial Development of An Amphibious ROV for Use in Big Surf." Maritime Technology Society Journal; Volume 28, Number 1, Spring 1994.

2. South, Todd "Marines want to use artificial intelligence to help find and neutralize sea mines." Marine Corps Times, 14 September 2018,

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