New Bisso tug reaffirms 20-year commitment to z-drives

Mr. Ruben 1

Mr. Ruben, constructed at Main Iron Works, is the 10th tugboat that the Houma, La., yard has delivered to Bisso Towboat of New Orleans. The last six, including the newest vessel, have been equipped with z-drive propulsion.

The boat’s namesake, Ruben Dupre Jr., joined Bisso Towboat in 1981 as marine superintendent and yard foreman, rising to vice president of engineering. Company President Scott Slatten explained that Dupre, now semi-retired and acting as a consultant and supervisor of new construction, was integral to the growth and modernization of the Bisso Towboat fleet.

“He and I were the ones who put our necks on the line back in 1997 when we convinced our president at the time, my father, Capt. Billy Slatten, to build the first ASD tractor tug for use on the river,” Slatten said. “I’ll never forget when he told us both, ‘If these z-drives don’t work out on the river, you’re both gonna be looking for a job.’”

In 1999, Bisso Towboat took delivery of the 100-foot Cecilia B. Slatten from Main Iron Works, beginning the era of z-drive tugs working on the Mississippi River.

Mr. Ruben is powered by twin Caterpillar 3516 T3MPL mains producing a total of 4,480 hp, coupled to Rolls-Royce US 205 FP azimuthing stern drives. The bollard pull is 60 tons and top speed is 12 knots. Two 99-kW Marathon generators are powered by John Deere 4045AFM85 Tier 3 diesels.

Capt. Mike Hilton mans the helm to help dock the bulk carrier Grand Marcia at the Zen-Noh Grain terminal in Convent, La.

On the bow is a JonRie Series 230 hydraulic auto-tensioning hawser winch with 500 feet of Samson 8-inch AmSteel Blue line, a stainless-steel H-bitt and a stainless-steel staple. On the stern are a Washington Chain & Supply RSRH-100 100-ton capacity tow hook and a stainless-steel H-bitt.

Although all six z-drive tugs are 100 by 38 feet, they have changed from the EMD-powered Cecilia B. Slatten and Alma S. The 4,000-hp Michael S. and William S. are Cat-powered. And with William S., Bisso Towboat made the switch from HVAC air conditioning to a keel-cooled system.

“It’s extremely efficient,” said Jon Davis, port engineer at Bisso Towboat. “The forced air is constantly being cooled by the river water. It is not only more comfortable in the tug, but the company is saving money on maintenance costs.”

A big change built into Becky S., delivered in 2015, and repeated with Mr. Ruben is a 6-foot mudroom extending aft of the house, allowing for a second head and isolated engine room access. A big hit with Mr. Ruben’s crew is the introduction of an Intellian tracking system that allows for a continuous television signal anywhere on the river.

Mr. Ruben also features glistening Spanish cedar and fine joinery in the pilothouse, a signature of vessels built by Main Iron Works.

“The last 18 years have proven us right, as we are building our seventh ASD tractor tug as we speak,” Slatten said. “Eventually, we would like to have a 100 percent ASD tractor tug fleet.”


Chief engineer Kevin Beudreaux starts one of the ASD tug’s two Caterpillar 3516 T3MPL mains. The engines, coupled to Rolls-Royce z-drives, can produce 4,480 horsepower.


Mr. Ruben’s crew consists of Capt. Hilton, Beudreaux, mate Sean Fortier and deck hand Michael Becnel.


Mr. Ruben’s JonRie Series 230 hawser winch is wound with 500 feet of AmSteel Blue line from Samson Rope.


The tug maneuvers to assist Grand Marcia.


By Professional Mariner Staff