Sunshine, La.-based Chem Carriers christened its second Z-drive towboat on the New Orleans waterfront in September.

The 2,520-hp Frank Banta Jr., which has an operating draft of only 8'3", is designed to ply areas with low-height restraints. A joint project with Rodriguez Shipbuilding, Bayou La Batre, Ala., Chem Carriers said the new 90'×30'×10' towboat is the first Z-drive towboat with a retractable pilothouse.

About two years ago, Chem Carriers took delivery of its first Z-drive towboat, the 1,400-hp Brooke Banta. The 70'×28'×8'7" Brooke’s propulsion package includes a pair of ZF Marine AT 4111 WM–FP azimuth Z-drives and Mitsubishi S6R engines. The Frank Banta Jr. has a pair of Mitsubishi S12R engines that produce 1,260 hp each at 1,600 rpm. The engines power a pair of ZF 6000 azimuth Z-drives with ZF 73"×55" 5-bladed stainless steel wheels in nozzles.

Chem Carriers has been pleased with the Brooke, pointing out that Z-drives have a much better fuel efficiency. 

“Our goal is to design and construct vessels that have lower fuel burn rates, are more versatile for our customers and improve crew accommodations,” said Warren Berthelot, the company’s chief engineer. “The Z-drives are really efficient. They don’t burn any fuel.”

To make the Frank Banta Jr. even more efficient, Berthelot said they gave it a “tunneled stern.” “The Z-drives are pretty well protected.”

In the hull, there’s 1/2" plate on the bottom, 5/8" at the stern, and a 3/4" plate transverse inserted for the main engines.

“We also paid a lot of attention to crew comforts, working to reduce noise and vibration wherever possible,” said Berthelot. “Everything is shock mounted. The generators are double shock mounted.”

The company also used rubber-inserted couplings between stationary piping and pumps. The entire engine room is insulated and sheeted with perforated aluminum, and all exhaust silencers are hospital grade to help further reduce noise levels. The floor is installed over mineral wool insulation and five-quarter plywood with Hardie board overlay. There’s ceramic tile in the galley and corridor, and crown molding throughout the essel. There are accommodations for 10 including three queen berths.

Rodriguez handled construction of the steel towboat’s hull and superstructureand then Chem Carriers’ engineering department took over, completing construction at the company’s Plaquemine Point Shipyard in Sunshine. Chem Carriers handled all equipment installations. 

The retractable pilothouse system uses four telescoping tube structures that utilize three square tubes and guides in each. These units also have air brakes that lock up the units at the end of each trip, furnished by Main Iron Works, Houma, La. The system has two redundant air tanks for emergency brake release. The retractable pilothouse ladder system keeps steps on a level plane at any pilothouse height.

Other features on the Frank Banta Jr. include fueling systems with meters for barges with grounding straps and high volume fuel discharge to other vessels or shore storage. The potable water system features double-bottom coated tanks that utilize dual pumps, charcoal filters and a UV system if bacteria is present. 

Chem Carriers has anotherZ-drive towboat underway atMain Iron Works. It will be a 2,000-hp two-level with a retractable wheelhouse. Delivery is scheduled for April 2015. The company now has 11towboats and 38 inland tank barges — 27 are 10,000 bbls. and 11 are 30,000 bbls. 

— David Krapf