ALL Crane Rental of Alabama, a member of the ALL Family of Companies, assists Gulf Coast shipbuilders with production aspects that require heavy lift equipment, particularly boat roll, also known as a hull turn.
A boat's bottom, the hull, is built upside down. The hull must be flipped over so the boat's top can be joined with it. A steel hull can weigh hundreds of thousands of pounds, so cranes are needed to get the job done, according to ALL.
ALL supplied cranes to flip a 613,000-lb. tugboat hull for Blakeley BoatWorks in Mobile. The Alabama branch provided two all-terrain (AT) cranes, a 550-ton, Liebherr LTM 1450-8.1 and a 500-ton Liebherr LTM 1400-6.1. A third crane, a 220-ton Manitowoc 14000 crawler, was Blakeley's own.
"In addition to the operators, we also provided the rigging, riggers, and signalmen," said Scott Swearengin, sales representative of ALL Crane Rental of Alabama.
In a three-crane boat roll, the highest-capacity crane, in this case the Liebherr LTM 1450-8.1, acts as the primary crane. The second-highest capacity, the Liebherr LTM 1400-6.1, provides the turning force and the third, the crawler, is the stabilizing crane.
Each crane is rigged to its own lifting eye, temporary welds strategically placed by the shipbuilder to help ensure equal load.
"At a certain point in the lift, the Liebherr LTM 1450 moves forward to pick it the hull off the ground and move it to a steel cradle," said Swearengin.
The cradle is the support structure designed specifically for that hull.
With the hull safely upright and transferred to its steel cradle, Blakeley BoatWorks could move on to the next phase of construction.
This story also appears on Crane Equipment Guide.
