VESSEL REVIEW | Versatile and manoeuvrable bridge erection boats for Puerto Rico Army National Guard

Birdon, through its US-based company Birdon America, recently handed over fourteen M30 Bridge Erection Boats (BEBs) to the US Army National Guard to replace the Puerto Rico Army National Guard's aging MKII boats that served the same purpose for over 30 years.

The primary mission of the 23- by 10-foot (seven- by three-metre) BEB is to provide tactical float bridging and rafting operations worldwide. The BEB is designed, built, and equipped to provide propulsion and manoeuvrable thrust to support floating bridges often made necessary when existing bridge crossings have been destroyed in conflict or by natural disasters.

The craft can also operate as patrol vessels in combat bridging operations and are transportable by road, rail and air. They are also used for reconnaissance, search and rescue, diving missions, transportation of troops, towing, and other types of natural disaster relief activities.

The army's Program Executive Office for Combat Support and Combat Service Support out of Warren, Michigan, has been overseeing the BEB construction project since the US$252 million contract was awarded to Birdon in 2013. Representatives said many upgrades have been incorporated into the design of the M30 to make the boat easier to maintain, launch, and operate.

The M30 is powered by twin Cummins QSB6.7 EPA Tier III-compliant, multi-fuel engines each rated 248 hp (184 kW) and driving NAMJet TJ38IHH hydrojets via ZF gearboxes. The hydrojets differ significantly from conventional waterjets in that they pump more water at lower revolutions, allowing each boat to reach speeds of up to 26 knots. This also allows increased propeller tip clearance to enable the jet to operate in more severe water conditions while allowing a higher bollard pull. This was in fulfilment of an army requirement for the hydrojets to be able to operate without damage in abrasive and debris-littered water conditions.

The Cummin engines can operate on JP-8 and F-24 jet fuels and ultra-low sulphur diesel while the onboard tanks can each carry twice as much fuel compared to the MKII craft.

In addition to being slightly wider and shorter than the MKII, the M30 only requires a two-person crew, freeing up additional onboard space for equipment. Contributing to the ease of use is a new twin-lever throttle control assembly and embedded diagnostics. The troop-carrying capacity is limited to six compared to the MKII's 15, though army boat crews appreciate the improvements in power and manoeuvrability evident in the newer craft.

The M30 was designed so that necessary repairs on the boat may be carried out even when on the water. This was not possible with a MKII boat, which was cable-operated. If the cables snapped while the boat is underway, repairs cannot be performed.

The M30s also boast the ability to be transported using the army's Common Bridge Transporter and the M15 Bridge Adapter Pallet, both of which are common to multi-role bridge companies in engineer battalions.

The 14 BEBs delivered to the Puerto Rico Army National Guard are part of an order for over 500 similar boats that Birdon will supply to various US Army units. All are being built in Birdon's facilities in Denver, Colorado. The army said the BEBs each have a projected service life of 20 years.

Click here for more news stories, feature articles, and vessel reviews as part of this month's focus on marine projects.