What’s better than good vibrations? How about no vibrations? That’s what crews are feeling on two Mississippi River towboats equipped with a system that eliminates almost all shaking and rattling.

Air bellow systems are among the creature comforts inland operators are adding to towboats along with features such as workout rooms, Z-drives for maneuverability and fuel savings, and wheelhouses with larger windows for more visibility. Designers and yards are busy, some with replacement equipment, others with newbuilds propelled in part by the energy market.

“Everybody wants something very special,” said Christian Townsend, naval architect with CT Marine, Edgecomb, Maine. With his dad Corning, he designed the 143'×50'×11' Ron Hunter, the largest towboat in Hunter Marine Transport’s fleet. Its entire cabin is mounted on 45 air bellows from Loggers BV, a Netherlands company. Gulf Island Marine Fabricators, Houma, La., built the vessel and it entered service in April. It is operates from St. Louis to New Orleans.

“The entire crew is just amazed at how quiet the boat is. It’s almost too quiet,” said Danny Whitford, vice president of operations for Nashville, Tenn.-based Hunter Marine. The 8,000-hp towboat is powered by two EMD 16-710 engines. 

Whitford, who oversaw the project, rode the towboat for several days out of the yard. “It’s extremely smooth. You don’t feel anything.” Whitford said he’s received inquiries from other operators about the system.

 “There are a lot of boats out there today running with cabins mounted on springs,” he said. “Where we’ve got air bellows, they’ve got springs.”

The system adjusts pressure to maintain stability as the vessel moves. Introduced about 25 years ago, the air ride cuts the vibration level in the upper deck about 98 percent, said Dirk-Jan van Ramshorst, of Loggers.

System cost depends on the weight of the superstructure that needs to be isolated, van Ramshorst said. Operators say benefits can be measured in crew comfort and more stability for sensitive electronics.

Hunter Marine and AEP River Operations are the first two U.S. inland operators to use the Loggers system.

AEP retrofitted the 183'×54'×10'6" Jeffrey G. Stover, which it purchased several years ago from American Commercial Lines. The former Miss Kae-D was repowered with three EMD 16-710s engines which increased the horsepower from 9,600 to 11,100, making it one of the most powerful towboats on the river, said Joe Brantley, AEP’s senior manager, operations support. 

The linehaul towboat, which runs from Cairo, Ill., to New Orleans, had some vibrations at the top of the wheelhouse, Brantley said. The rest of the boat was very smooth, and they wanted to eliminate the vibrations without losing horsepower. “We looked at taking the wheelhouse off and isolating that on the air ride system,” he said. That did the trick, Brantley said, and “it really made it smooth.”

“Ours was the first one out running on the river,” he said.

 AEP put eight air bellows under the wheelhouse while the boat was at James Marine in Paducah, Ky. It returned to service in the first quarter, said project manager Van Henson. “Now it’s a difference between daylight and dark,” he said. “You can hardly feel any movement.”

As for the crew feedback, “they love it,” Henson said. AEP would consider retrofitting other wheelhouses that are on springs.

 Many clients “are looking at more and more comfort for the crew,” said Tommy Parfait of Parfait Maritime Designs, Daphne, Ala. They want something different than in the past.

“A lot of operators are putting in ceramic floors. They’re just going to finer materials,” he said. Towboats are now designed to have less noise, bigger staterooms and galleys, more heads and exercise rooms.

He’s designed a 75-footer with four tiers and a workout room with stereo equipment in a cabin set below the pilothouse.

 Parfait is also seeing more requests for bigger windows. “All are asking for almost full windows on the front for visibility and safety,” he said.



Z-drives are becoming more prevalent on the inland waterways. Parfait hasn’t done a Z-drive yet, but he knows that they handle well and “you don’t have all those shafts to constantly pull out,” he said.

The U.S. Army Corps of Engineers is putting Z-drives on its new towboat under way at Horizon Shipbuilding, Bayou La Batre, Ala., for the Little Rock (Ark.) district. The $11 million contract for a 95'×43'×10' replacement for the Shorty Baird, built in 1977, is the latest of three recent Corps contracts for Horizon, which earlier delivered the 114' George Grugett and the 58' General Irwin.

The Corps wanted Z-drives “for the increased maneuverability due to where the vessel has to operate,” primarily in restricted areas, said Timothy Keyser, chief, hull section, of the Corps’ Marine Design Center in Philadelphia. And they get more horsepower for the dollar. A 2,500-hp Z-drive is comparable to a 3,000-hp conventional drive, and it has an estimated 8% to 9% fuel savings, he said.

The new towboat’s Thrustmaster TH1500MZ Z-drive azimuth thrusters will be driven by two Caterpillar C32 Tier 3 engines putting out 1,300 hp each.

The Corps has two Z-drive towboats, the Ward and Lusk, and two Z-drive dredges, the Hurley and Murden. The new towboat hasn’t been named yet. 

Another reason for the Z-drives is that they and the box coolers — instead of keel coolers — can be removed and replaced while afloat in eight hours, said Keyser. “From where the vessel operates, the closest drydock is several days away. We expect a large reduction in downtime,” he said.

Horizon, which has built Z-drive vessels in the past, expects to deliver the Corps boat in the third quarter of 2015.

“Horizon has seen an active towboat market for the past seven years, both in bid activity and bids won,” said president Travis Short. “We currently have seven towboats in various stages of production. Overall, the towboat market is very strong, and we don’t see any evidence that it will slow in the next year or two.”

American Commercial Lines is building a series of eight 2,000-hp Z-drive towboats at Steiner Shipyard. The four 70'×28' fleet boats and four 75'×34' canal boats are the first series of new towboats for ACL in 25 years.The Bayou La Batre yard built a series of four 3,800-hp Z-drives for Southern Towing in 2008-2009. 

Magnolia Marine Transport, Vickburg, Miss., is among the operators also adding equipment.

The recently delivered 3,000-hp Miles Madison is “doing a great job,” said Dino Ross, senior vice president of marine engineering. The company expects to take delivery of four more 110'×32', 3,000-hp towboats from Nichols Boat Co., Greenville, Miss., through 2015.