Q&A with ZF Marine: Inside ZF’s evolving approach to inland propulsion

Sponsored Content: As inland vessel operators continue to balance performance, efficiency, and evolving environmental expectations, propulsion technology has become an increasingly important part of the conversation. From harbor maneuvering to long-distance towing operations, thrusters that can deliver reliability while also supporting future-ready propulsion strategies are in growing demand across the inland waterways sector.

ZF has been part of that evolution for more than a decade. As one of the first companies to introduce commercial thrusters into the inland market, the company has continued refining its AT thruster series with expanded horsepower ranges, hybrid-ready configurations, and advanced control technologies designed to improve maneuverability and operational efficiency. In this Q&A, Marine Log‘s Heather Ervin spoke with ZF’s Walter Fienco, Project Manager for Government, Commercial Thrusters, and Special Projects, about what the company has learned since entering the inland market, how hybrid propulsion is shaping vessel operations, and how operators can prepare their fleets for a more sustainable future.

Heather Ervin (HE): ZF was the first to provide commercial thrusters to the inland water space. What has the company learned since then and how have you made improvements since they were introduced?

Walter Fienco (WF): ZF is honored to have supported tugboats, towboats, barges, and vessels operating within the inland waterway system for more than a decade. Entering the market as an early innovator inevitably presents challenges; however, I am proud that ZF’s solutions have not only endured but have consistently demonstrated reliability and benefited from ongoing refinement and technological advancement. Moreover, we have broadened our AT thruster product portfolio to encompass a wider range of horsepower capabilities and to integrate enhanced functionalities such as ZF autotroll and hybrid-ready configurations. ZF’s proven autotroll technology combined with an electric drive allows maneuvering at idle engine speed without clutch damage, a major operational benefit. This enhances safety and operational agility in dynamic harbor and waterways.

As ZF remains steadfast in its commitment to advancing its marine propulsion offerings, this thruster series continues to deliver exceptional performance and to fulfill its core mission of supporting operators throughout America’s inland waterways and harbors.

HE: Can these thrusters be retrofitted or adapted to existing hull designs, or are they only for newbuilds?

WF: One of the AT series’ strongest selling points for commercial operators is its extreme flexibility. It is fully customizable to nearly any hull shape or vessel profile. Whether you are operating a traditional pusher tug or a specialized barge, the well-mounted Z-Drive configuration can be tailored to match your specific vessel geometry.

HE: What operational advantages does the hybrid Power‑Take‑In (PTI) setup offer beyond just fuel savings?

WF: Beyond improving operational efficiency, the hybrid configuration also serves as an auxiliary power source, providing additional thrust for obstacle avoidance or enabling increased transit speed during time‑critical operations. For specialized vessels—such as firefighting tugs—the system removes the necessity for costly controllable‑pitch propellers; the diesel engine can supply power to the firefighting pump while the electric motor independently drives the thruster, thereby reducing mechanical complexity and distributing system load more effectively.

Operating in hybrid mode also minimizes clutch wear, lowers gearbox loading, and reduces vibration and thermal stress throughout the propulsion train. The PTI electric motor further enhances performance by functioning as a supplemental power booster, offering improved responsiveness and rapid thrust delivery when required. In addition, hybrid‑ready architectures support long‑term fleet modernization by enabling operators to transition progressively toward more environmentally sustainable propulsion solutions.

HE: How does ZF help operators meet “green” goals?

WF: The ZF AT Series is engineered for seamless integration into hybrid and fully electric propulsion architectures. By incorporating an electric motor at the PTI, vessels are able to execute full‑electric maneuvering and low‑emission sailing within regulated waterways, thereby reducing both acoustic footprint and overall environmental impact. This operational capability also positions vessels substantially closer to achieving CLEANSHIP‑class certification by demonstrating measurable reductions in emissions and noise output.

Furthermore, ZF has implemented a specialized seal arrangement compatible with Environmentally Acceptable Lubricants (EALs). This design minimizes ecological risk in the event of a seal failure, mitigating the potential for significant environmental harm as well as the financial and reputational liabilities commonly associated with spills involving conventional mineral‑based lubricants.

In addition, ZF thrusters feature hydrodynamically optimized underwater housings engineered to reduce drag, improve cavitation performance, and enhance propulsion efficiency. These design optimizations contribute directly to lower carbon emissions and decreased operating expenditures through improved thrust efficiency.

HE: What kind of technical support is available if we encounter a propulsion issue in a remote waterway?

WF: Reliability is backed by a 24/7 global customer service hotline (+1-833-ZFWRENCH). Additionally, operators can use the ZF mobile app to manage product needs and warranty information directly from their devices, ensuring that technical assistance is available even when you aren’t at a desk.