Z-drive and retractable towboats are becoming familiar sights on the U.S. inland waterways. But when they’re combined in a broad-shouldered, single-deck linehauler that can cut up to two-and-a-half days off an east-west Intracoastal Waterway passage and do it in style with the lowest possible fuel burn, people are going to take notice.
The 2,520-hp Capt. Frank Banta Jr., jointly designed by the owner, Chem Carriers of Sunshine, La., and the builder, Rodriguez Shipbuilding of Bayou La Batre, Ala., has the maneuverability of a DP-class supply vessel and the air draft of a crewboat, while pushing up to 1,170' of barges on the trickiest U.S. waterways. Chem Carriers said the new 90'×30'×10' towboat is the first Z-drive towboat with a retractable pilothouse.
“The efficiency of modern Z-drives is phenomenal,” said Warren Berthelot, director of newbuilding for Chem Carriers. “There’re a lot of reasons, including directing all thrust in the desired direction, and the reliability and ease of maintenance. But for a lineboat dealing with a long tow, cross-currents and other traffic, the maneuverability of its stern Z-drives offers a tremendous safety factor.”
“Z-drives have a much better fuel efficiency per horsepower and thrust ratio,” said Frank Banta Jr., owner and president of Chem Carriers, who added that the company has been considering the conversion from conventional drives for several years.
A willingness to innovate that distinguishes Chem Carriers’ designs, including its previous Z-drive towboat, the 70'×28'×8'7" Brooke Banta, can be seen throughout the Capt. Frank Banta Jr. The unique single-piston elevating wheelhouse, with its cantilevered retracting radar masts and elevating rear companionway, is one of the most obvious, but the care and thought given to the design extends down to the rubber vibration-isolation mounts for the generators and motors.
“This boat even has rubber mounts for the starter panels,” said the Banta’s master, Capt. Neal Garon. “With [the generators’] hospital-grade mufflers, the isolation mounts, and the triple-layer sound-deadening flooring, this is the quietest, smoothest riding boat I’ve ever been on.”
Garon’s point was well taken. He was speaking in a conversational tone just two feet behind a main generator’s rear-facing exhaust.
And the boat’s attention to amenities for its five-person crew, each in a private two-berth cabin, contributes at least as much to their well being. “It’s hard to get and keep good crews these days,” observed Berthelot, “but our boats aren’t comfortable just for that. We really do think of these boats as our crews’ homes. It’s more than things like soft bunks and hot water showers. It’s the entire environment onboard.”
The company’s care for its crew includes a potable water system with double-bottom, coated potable-water tanks (all ballast tanks in the vessel are potable-water tanks), dual pumps, charcoal filters, and an ultraviolet purification system.
The care also includes the crew’s physical surroundings. Natural-wood fittings, like the ornate crown molding, wainscoting and exotic pecan-wood floors, are found throughout. “We had hundreds of beautiful old pecan trees at our company property that were blown down in [Hurricane] Gustav,” Berthelot said, “so we had them cut and planed into planking, and some of it went into the boat’s beautiful walls and floors.”
It’s unusual for a boat captain to wax poetic about his boat’s comfort features, but Garon was clearly proud of them. “Touch faucet in the galley,” he said, demonstrating, “so if your hands are dirty you can turn the water on with your elbow. Built-in surround-sound for the television and stereo. Individual hotel-unit air conditioners. And the near-silence in the cabins, even when underway. There’s nothing like working hard in comfortable circumstances.”
The comfort extends to the wheelhouse as well. All controls are within arm’s reach from the operator’s chair, and a 13-camera closed-circuit monitoring system with simultaneous displays on the large-screen monitor in the wheelhouse provides the wheelman with a view of every part of the vessel except the tanks. A touch-screen display about the size of a laptop-computer screen offers access to all vessel systems from the operator’s chair. Similar screens in the galley and engine room do the same.
“Gone are those huge panels with hundreds of gauges and read-outs,” Garon said. “The boat’s central-computer branching program let us access every system on the boat from these little screens.” He demonstrated by switching quickly from engine performance displays to electrical displays to ballast-tank levels. “All our young crew are tech-savvy,” he said, “so accessing whatever we need on these screens comes naturally to them.”
Another nice touch is the indicator panel in the galley with a light for every pump onboard. “Anybody in the galley can look up and see what’s running,” Garon said, “and if some pump, like a bilge pump, is coming on too often or at the wrong time, we’ll know it.”
Some of the design’s most innovative features aren’t as visible. The hull’s underbody was carefully balanced for minimum draft, using a double-chine section with deep tunnels for the drives. “We were well-aware of the dangers presented to Z-drives in an inland environment,” Berthelot said, “so we put them as high in the hull as possible, and we haven’t seen any diminution in performance.” Raising the drives into tunnels also helped to give the design its shallow 8'4" draft.
TIME AND FUEL SAVINGS
The thought, expense and effort that went into reducing the vessel’s water and air drafts have provided significant benefits. “On some of our regular routes, conventional towboats have to either make extensive detours around shallow waterways or, more commonly, around low bridges,” Berthelot said. “We studied every single restricted draft and restricted height location on our regular runs in designing this boat. The savings in time and fuel can range from hours to days, and with no penalty in power, maneuverability, or efficiency, only in initial cost. And with the longevity we built into this boat, that cost will be amortized over many, many years.”
To get under the low spots and still see over the tow, the wheelhouse, at 35'3" high fully extended, can be lowered to a minimum air draft of 19'7". With radars and antennas down, the boat is only 17' high.
The custom-designed and -built elevating system uses a single massive vertical piston in the center of the wheelhouse to raise it, with four guide tubes at the corners. Air brakes lock the wheelhouse in place to prevent accidental lowering. And the operator can maneuver the vessel with the wheelhouse at any elevation.
“Heck,” Garon pointed out, “even the companionway goes up and down with the wheelhouse. You can enter and leave at any point.”
To keep the steps level at any angle, the companionway is cantilevered like the radar masts. The extremely tight fit between the moving members of the radar masts and the companionway, and the apertures cut out for them in the wheelhouse and accommodations, are testament to the precise calculation and fit that construction required.
“We had a good arrangement with Joey [Rodriguez],” Berthelot said. “His yard built the hull and superstructure and we took it from there. That way, when it came to equipment and fitting-out, we had a free hand.”
With ½" plate on the boat’s forward bottom and 5/8" plate at the stern, and a ¾" transverse reinforcing frame under the main engines, the vessel has a strong and stable platform from which to exert its 68,000-lb. bollard pull.
The two Mitsubishi S12R diesel engines, each producing 1,260 hp at 1,600 rpm, drive a pair of ZF 6000 Z-drives with ZF 73"×63" stainless-steel 5-bladed propellers.
Two John Deere/Stamford generators, each producing 99 kW, supply ship’s service power.
“This boat’s maneuverability is amazing,” Garon said. “I’ve never had a boat that could drive a tow like this one. With conventional drives when you get sideways to the current you can get in real trouble, but with Z-drives you just turn them in whatever direction you want and that’s where you go.”
Two fire monitors behind the wheelhouse can supply water to fight a fire on the boat or tow, and a fueling station amidship has metering so the boat can pump fuel from its 28,000-gal. diesel tankage to other vessels.
With 11 towboats in its fleet, Chem Carriers isn’t resting on the Banta’s laurels. The company has already commissioned a yet unnamed third Z-drive towboat from Main Iron Works in Houma, La. It will be a 2,000-hp two-deck boat with a retractable wheelhouse. “This one is going to be really interesting,” Berthelot promised. “The wheelhouse will nest inside the second deck, so it won’t be much higher than [the Frank Banta]. And we have some more ideas we want to try out on that one.”
If the Capt. Frank Banta Jr. is any indication, those will be interesting ideas indeed.
CAPT. FRANK BANTA JR. SPECIFICATIONS
Builder: Rodriguez Shipbuilding/Chem Carriers
Designer: Rodriguez Shipbuilding/Chem Carriers
Owner: Chem Carriers
Mission: Tow barges on the inland waterways
Maximum Draft: 8'4"
Main Propulsion: (2) Mitsubishi S12R, 1,260 hp @ 1,600 rpm
Z-Drive: (2) ZF 6000
Bollard Pull: 68,000 lbs.
Ship’s Service Power: (2) John Deere/Stamford 99kW
Propeller: (2) ZF 73"x63" stainless steel, 5-bladed
Speed: 6-7 knots
Hull Construction: Steel double-chine
Crew Capacity: 10 in five double-berth cabins
Electronics: Furuno radars; AIS; VHF radios
Tankage (gals.): Fuel, 28,000; potable water, 8,000; lube oil, 250; hydraulic oil, 250
Ancillary Equipment/Systems: (2) fire monitor; hydraulic elevating pilothouse
Classification/Certification: USCG inspected towing vessel
Delivery Date: September 2014