Barnhart’s Mandan, North Dakota branch was hired to provide engineering, crane, and transport solutions to launch a new 80-foot-long riverboat in New Town, North Dakota. The riverboat was fully constructed on-site about a quarter of a mile from the lake. The boat’s interior was not fully outfitted when the project took place. The center of gravity (CG) was estimated, but Barnhart decided to include hydraulically adjustable tension links in the rigging to have the ability to level the boat in case the actual CG was offset from the theoretical location.
The boat was transported down a 16.8% grade several hundred yards on a PST double-wide 12-line Goldhofer to reach the launch site. The crane with counterweight was walked down the same incline to the second crane pad. This road was constructed using only native materials, which presented significant challenges including scheduling conflicts and soft areas difficult for the Goldhofer to navigate.
To avoid damaging the thin plate of the hull, the transverse slings under the hull were positioned at predetermined locations at internal frames and bulkheads. Adjustable rigging and multiple spreader bars were engineered to accommodate the lift.
Barnhart used its CC 2800-1 SSL crane and 300-kip and 120-kip tension links to pick the boat from the Goldhofer and successfully set it in Lake Sakakawea. The project challenges included changing river elevations and river flow rate, heavy rain causing road and crane pad washouts and working over open water.