The process is called downstreaming. It involves positioning a towboat above a fleet of barges, then using the river’s current to move the vessel downstream, plucking the needed barge from the fleet.
Now imagine that it’s late April on the Lower Mississippi River, between Baton Rouge, La., and New Orleans. The water is high and the current is, as they say, “running.” This is the type of situation where vessels can sink and lives can be lost. It can be dangerous. But the cargo in the barges is needed. The owners can’t wait until the water goes down and the current slows to get at their cargoes.
This is the very scenario that convinced Carline Companies, Gonzales, La., to build a new 1,500-hp fleet towboat — one with a lot of maneuverability that can handle downstreaming no matter what the conditions.
Carline offers fleeting services in Louisiana on the Lower Mississippi River at Burnside, Geismar and Plaquemine. And that’s where the company’s new 68'×34'×10' fleet towboat Cairo will be used. (The company also offers continuous barge moves on the Mississippi River between Baton Rouge and New Orleans and between New Orleans and Houston on the Gulf Intracoastal Waterway.)
“This is the first boat that we’ve had built that is specifically for fleeting operations,” said Clay Harmon, Carline’s vice president. “We’ve always used some of our older linehaul boats as fleet boats, and they work fine. But this boat increases the efficiency in the fleet.” It also increases safety because it’s two Z-drives give the vessel added control.
“I would say that the main difference between this boat and the other fleet boats is better maneuverability,” said Capt. John Michot, one of the Cairo’s pilots. “It’s definitely better.”
SPECIAL ORDER
Carline contacted CT Marine, Portland, Maine, in late 2012 about designing a fleet boat with similar visibility in the wheelhouse that a CT-designed Parker Towing linehaul towboat had. A deal was struck at that year’s International WorkBoat Show in New Orleans.
“I think we were just going to design the wheelhouse at first,” said CT’s Christian Townsend. “Then we wound up designing the whole boat. It was the first Z-drive towboat for us. We had wanted to do one.”
The Cairo is the first Z-drive towboat for Carline and the first CT Marine design with Z-drive propulsion to be built.
The wheelhouse is octagonal, set as close to mid-ship as possible, and features floor-to-ceiling windows for a 360° view. “It’s as close to 360 degrees as we can get it,” said Townsend.
“It’s mainly for the captain to have a better line of sight, all around visibility,” said Harmon.
The challenge was to take a design that was already proven and put it into a much smaller package. “It was one of the more difficult boats for us to design, putting all that equipment, like the pumps, into a much smaller envelope,” said Townsend.
Harmon worked closely with CT Marine during the design process. “We were given a virtual tour of the boat,” he said. “It really gave us an opportunity to see what it would be like to walk into the different sections of the boat. It really helped.”
Townsend said the new towboat has the scantlings of a much larger boat. “It’s way overbuilt,” he said. “I tried to put as many big boat attributes into this boat as we could. Stability wise, it’s a real bulldog fighter.”
Though the Cairo is a day boat and has no berths, the vessel has plenty of amenities, including a full galley, with large screen television on one wall, two heads and a training room. “Yes, amenities definitely matter,” said Harmon. Each three-person crew works a 12-hour shift and goes home after each shift, working days one week and nights the next.
Finding young men and women coming out of high school to commit to the marine industry is not always easy, Harmon said, “but we’ve done pretty well with the people we have. To be able to tell them that in six years you can be a pilot and make some real good money helps. And they go home every day.”
MANEUVERS
A pair of Thrustmaster of Texas TH750MZZ-drives provide more control from the wheelhouse. The Cairo was specially built for fleet duty, nothing else. “There will be times when [the pilot] has to have both hands on the controls,” said Harmon, “that’s why we had a foot mic [microphone switch] put in.
“That was Clay’s idea. I had never seen that before,” said Townsend. “It’s really a good idea. He’s been in the business a long time, and he has some good ideas. This boat is definitely his project.”
“The main reason we went with the Z-drive boat was downstream safety because of high water,” said Harmon. “There are specific jobs that call for downstreaming in high water conditions.”
Rick Stinson, Thrustmaster’s Gulf Coast regional sales manager, said Z-drives give the operator more control in any conditions. “They knew that. I think the reason they selected us is because we were the only U.S. manufacturer of Z-drives, and we offer parts support, reliable service and our products are built to ABS standards.”
Years ago two of the knocks against Z-drives on the river were the amount of debris that could get sucked into the drives and the expense and downtime needed to get replacement parts. “We have $20 million in spare parts inventory at all times and we’re in Houston,” said Stinson. “Our drives have what we call a mechanical fuse that fires if something big like a towline or cable is ingested. Replacing a prop is easy enough. The fuse protects the bearings, gears, crankshaft, flywheel, like a shear pin on an outboard motor.”
Stinson said his numbers show average fuel savings of 25% over comparable boats with rudders. “These drives eliminate the need for flanking rudders, and rudders rely on deflected thrust which uses a lot of power,” he said. “You’re using your engines at higher rpms with rudders, burning more fuel.
Stinson said Thrustmaster has numbers that show that Z-drive boats are more efficient than conventional vessels. “What we’ve seen is a 1,500-hp Z-drive can perform like a 2,000-hp conventional propulsion boat,” he said.
The Thrustmaster Z-drives connect to a pair of Cummins QSK19-M Tier 2 diesels, producing 750 hp at 1,800 rpm each. The Cairo’s capacities include 16,819 gals. of fuel; 2,971 gals. potable water; and 415 gals. each of engine lube oil and Z-drive lube oil.
“We were all curious about the boat, excited really,” said Capt. Michot. “It’s all been pretty smooth so far.”
Harmon said the crews are still learning. “They’ve all been sent to simulator school.”
One of Harmon’s favorite features of the boat is the technician’s room, which houses an impressive system of monitors. “Technicians can come in here and check the monitors for a complete history of, say, the amount of fuel the boat has used. All in all, the boat came out very well. We’re pleased.”
CAIRO Specifications
Builder: Raymond & Associates/Carline Companies
Owner: Carline Companies
Designer: CT Marine
Mission: Fleeting/switch boat
Length: 68'
Beam: 34'
Depth: 10'
Draft: 8'
Hull Material: Steel
Steel Weight: 197 ST
Lightship Weight: 292 ST
Height of Eye: 33'
Main Propulsion: (2) Cummins QSK19-M Tier 2, 750 hp @ 1,800 rpm
Z-Drives: (2) Thrustmaster TH750MZ, 57" propeller in nozzle
Ship’s Service Power: (2) Cummins 6BTA, 85 kW, 1,800 rpm
Capacities (gals.): Fuel, 16,819; potable water, 2,971; lube oil, 415; Z-drive oil, 415
Electronics: Furuno electronics suite
Supplemental Equipment: Tank monitoring system, camera system, Palfinger knuckle boom crane
Crew Capacity: 3
Certification: Built to ABS standards
Delivery Date: December 2014
