Retractable Defensive Barrier (RDB)


The GUARDIAN retractable defensive barrier is a military-grade maritime gate designed to survive the harshest marine environments.


The GUARDIAN system can be connected to existing structures or to other HALO or third-party systems. Its modular design allows for manual or automatic gate operation, requires less stand-off distance and less maintenance than all legacy systems currently in-place, and has a life expectancy greater than 15 years.

Modular Design

Provides simplified maintenance and repair. Minor part replacements are quick and easy. The accordion style structure allows automatic operation in constrained waterways.

Gate Options

These options are available for either push button, automatic, remote control, or manual operation.

Installation Flexibility

Allows GUARDIAN to be installed with high-visibility colors or bespoke, architecturally pleasing paint schemes that blend the barrier with its surroundings.

Double-Walled Construction

Designed to stop boats on impact. HALO’s proprietary barrier technology transfers kinetic energy of an impact from the barrier to the water.

All of our HALO products are:

  • Capable of integrating oil abatement/containment systems.
  • Able to support third-party sensors (safety, security and environmental).
  • Marine mammal and environmentally friendly.
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Where can Guardian barriers be used?

Naval Bases
High-Value Assets
Critical Infrastructure
Nuclear Power Plants
Ports & Terminals
Oil and Gas Facilities
Restricted Waterways
Security Exclusion Zones
Government Facilities

The GUARDIAN barrier features a modular design that provides simplified maintenance and repair.

Accordion style structure allows automatic operation in constrained waterways. The double wall barrier, with diamond shaped segments, forms an impassible vertical wall in the water. The gate can be opened and closed in automatic, power-assist, or manual mode.

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Design Performance

HALO GUARDIAN meets the MIL-STD-810G standard.

MIL-STD-810 is a United States Military Standard that emphasizes tailoring an equipment’s environmental design and test limits to the conditions that it will experience throughout its service life. This standard establishes chamber test methods that replicate the effects of environments on the equipment, ensuring that all designs can be rigorously and consistently tested.

HALO GUARDIAN is the only barrier, or maritime gate, system that has been tested to meet the U.S. Navy Security Performance Specification for maritime security barriers.


Parameter SI USC
Freeboard (height off water) 2.4 m 8 ft
Beam (Width) 4.4 m 14.4 ft
Maximum Kinetic Energy Capability* >6,779kj >5M ft-lbf
Post-Impact Displacement 2.8 m 9.2 ft
US NAVY Specified Threat Boats Stopped >99.99% >99.99%
Meets or Exceeds United States Navy Requirements
Structurally Intact Post Impact
Gate Operationally Intact Post Impact
Maintains Protection Against Followup Attacks
* Maximum kinetic energy customizable to customer needs. Please contact us for details.

Integration & Customization

The GUARDIAN retractable defensive barrier can be fully integrated with other third-party security technology such as cameras, radars, sonar, etc.

  • Safety Systems – Additional safety systems can be attached to all HALO security products.
  • Radar and Sonar – Integrated payload capacity in all HALO security products allow for the attachment and integration of sonar and radar equipment.
  • Remote Monitoring – Remote monitoring of system performance and status.
  • Navigation Lighting – Mounting points for standard marine navigation lanterns and other Aide to Navigation (ATON) equipment.
  • Capture Nets – Extend your defensive measures below the surface. Capture and detection net mounting points are included on all HALO products.
  • Access Control – Know who is entering and leaving your protected area. HALO gate systems can be integrated with most any third-party access control solution and include mounting locations for RFID extenders.
  • Camera Systems – HALO’s unique barrier dynamics allow for stable deployment of IR and other CCTV security camera solutions.
  • Third-Party Sensing – Most any safety, security, and access control system is compatible with HALO barriers. The possibilities are endless.