Barnhart is known for moving oversize or heavy pieces in industrial or plant settings. But a project to move a 1940s-era battleship gun barrel ranks as one of its most unusual requests, it says.

The 16in diameter gun barrel, which was originally a part of the USS Iowa battleship, had been lying in a field at St. Julien’s Creek Annex in Portsmouth, Virginia, a US naval support facility. The Veterans Association of the USS Iowa and the Coast Defense Study Group, a non-profit corporation formed to promote the study of coast defences and fortifications, arranged to move and display the barrel at Fort Story next to the historic Old Cape Henry Lighthouse in Virginia Beach.

Rusting and lying in a large grass field at St. Julien’s Creek Annex, the project’s first phase involved getting the barrel into display-ready shape. To do that, it had to be transported to Marine Specialty Painting in Portsmouth, which specialises in government ship repair for refurbishment.

However, it had to be lifted first, which posed some challenges to the Barnhart crew. The 70ft-long gun barrel, which weighs 275,000lbs, was sitting in a ditch below ground level, so ground-bearing pressure was an immediate challenge. Barnhart used a 500-tonne one-shot gantry system on top of 6x20ft steel crane mats to improve the weight imposed on the soft soil.

The soil conditions also meant that the crew could not drive the trailer directly under the barrel once it was suspended in the air. Barnhart utilised 45ft-long multi-purpose girders (MPG) as header beams for the gantry arrangement. Slide shoes were used atop the girders to transfer the piece to more level ground. This arrangement allowed the trailer to have a direct shot under the piece as it was loaded.

More than 25 laminate mats were placed in the travel path of the trailer to prevent the load from getting stuck during transport back to solid ground once loaded.

Once the refurbishment was completed, it was time to transport the barrel to its final destination at Fort Story. At Marine Specialty Painting the barrel was loaded on the trailer and the 40-mile haul took about 3.5 hours and required police escorts.

On site, the Barnhart crew reversed the method used at St. Julien’s Creek Annex. The truck pulled underneath the 500t one-shot gantries and lifted the barrel off the trailer with three 45ft MPGs. From there, Barnhart utilised its slide system to shift the barrel over to the concrete pad and lowered it down.

The USS Iowa has a notable but tragic past. Launched in 1942, the ship served in both World War II and Korea. In 1989, an explosion occurred within a gun turret during a fleet exercise in the Caribbean Sea. The blast killed 47 of the turret’s crew members. As a result, the Navy decommissioned the USS Iowa shortly afterward.

The USS Iowa is now open to the public in the Port of Los Angeles as a floating museum.