Page 38: of Marine News Magazine (January 2016)

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INLAND PROPULSION

Driving the Inland

Waterways

Propulsion evolves, improves and powers forward in the inland markets. And, Z-Drive propulsion is the future.

By Joseph Keefe n a white paper released late in 2014 by The Shearer

Group, Ed Shearer and Greg Beers outlinedThe Next

IGeneration of inland vessels, what will drive design changes and the advantages of azimuthing stern drives – or ‘Z-Drives,’ for short. The authors point out that, until recently, towboats on all the inland waterways and Gulf

Coast have traditionally been built using main engines connected to reduction gearboxes connected to long drive shafts passing through the towboat hull. In a nutshell, according The Shearer Group, the advantages of using z-

Drives on inland towboats include decreased installation time, increased fuel ef? ciency, increased trip time ef? cien- cy, decreased maintenance downtime and higher customer satisfaction. In fact, savings in fuel and trip time from 10 to 30 percent have been shown to be possible – in theory and actual towboat operation.

In practice, the maritime industry tends to be conserva- tive, slow to adopt new technologies and measured in their approach when they do. Until recently, the use of Z-Drive propulsion units on inland towboats has not been taken seriously due to concerns about initial cost, maintenance and durability. But, that hasn’t stopped Z-Drive units from being used for many years on oceangoing and harbor tugs.

That’s because the Oil Pollution Act of 1990 (OPA 90) created a need for ship assist boats with greater maneu- verability and stronger pull/thrust than traditional design

Image: Schottel Image: Caterpillar ship assist tugs. In practice, two Z-Drive tugs can take the

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