Over the past two to three decades a few “different” tug designs have surfaced to test the waters of...
[By: Robert Allan]
Over the past two to three decades a few “different” tug designs have surfaced to test the waters of the ship-handling world. Some have died a quiet and worthy death, others have found strong but limited acceptance in niche applications. However the Z-Tech design, developed by Robert Allan Ltd. in 2003, has seen widespread international acceptance ever since, and now boasts 97 boats in active service, with a further 22 under construction. No “flash in the pan” this award-winning machine!
The Z-Tech story began for Robert Allan Ltd. in 2002 when Peter Chew of the Port of Singapore Authority (PSA) brought us a serious challenge. They had a need for new tugs to replace older vessels and add to their significant fleet. The PSA fleet comprised a random mixture of ASD tugs, some Z-drive tractors, and some Voith tractors. Different crews favoured different types, generally according to the type with which they were most familiar. Peter’s challenge to us was simple; “We need a single new design which incorporates the best features of both ASD tugs and Z-drive tractors.”
In response, Ken Harford and I went to Singapore and spent several days riding on tugs, riding on the attended ships, talking to tug crews and to PSA management, gathering input about how they worked in one of the world’s busiest ports, and watching their ship-handling operations. After about four days, Ken and I were having a well-earned beer after a busy day and brainstorming about how best to achieve Peter’s request. Ken had an “ah-ha” moment and described his thinking about how to do just that with the proverbial bar napkin sketch. I spent the evening doodling at a somewhat higher level and in the morning, we had the genesis of what was to become the Z-Tech design to discuss with PSA.
Ken’s concept was simple and quite brilliant: take a basic ASD tug, make its shape in plan more or less symmetrical fore and aft, but reverse the sheer line so it was lower “forward” than “aft” and move the house much farther “aft” than typical, making sure there were excellent sightlines in all directions, and the safest possible working environment for the crew.
This concept provides a large, clear and relatively level working deck around the winch when operating in the “ASD” mode (drives aft) and if towing or when rough weather transits were required, the tug could simply run going “stern first” in tractor mode (drives forward). Only one winch is required, saving space, weight and cost.
The first of these tugs, Indee and Pardoo, were built by Cheoy Lee Shipyards in 2004, and although ordered by PSA Marine they went directly into service with Teekay Marine as ship-handling/escort tugs in Port Hedland, Australia. These were followed in quick succession by an extended series of builds for PSA Marine themselves, for Lamnalco, Keppel Smit Towage and for Adsteam Towage, among others. This first generation of Z-Techs were 27.4 metres long by 11.5 metres beam and had 3,730 kW of diesel power, producing more than 60 tonnes bollard pull.
The distinctive Z-Tech concept attracted a lot of attention and jointly with PSA, Robert Allan Ltd. promoted the novel design as a candidate for a variety of industrial design awards. The year after the first Z-Tech tugs were delivered, the design received the Singapore Design Award, and in 2005 it won the prestigious German Red Dot International Design Award as the “Best of the Best,” competing against the likes of Porsche, BMW, and Bose.
Since the first Z-Tech series, the design has continued to evolve into larger and more powerful variants, and even in some cases more modestly powered variants according to the needs of our clients. Outside of Asia, the major adopters of the Z-Tech fleet have been G&H Towing, operating tugs on behalf of Bay-Houston Towing and Suderman & Young Towing in Houston, Texas. Other major clients include the Panama Canal Authority and the US Navy. The fleet in Panama bears some special mention, now numbering 21 authentic Z-Techs operating as the backbone of one of the busiest tug fleets in the world and in arguably one of the world’s most critical waterways.
Today, Z-Techs are operating in Australia, Hong Kong, Panama, Japan, Malaysia, Middle East, Singapore, Turkey, USA and Vietnam. Operators in Peru and Thailand will take deliveries in 2025. The design has continued to evolve, now offered in two distinct hull forms, with or without RAstar type sponsons depending upon the need for a tanker escort rating. Bollard pull ranges from 45 tonnes to 82 tonnes with lengths of 24 metres to 30 metres.
The Z-Techs have been built in 11 shipyards in China, Turkey and USA, however Cheoy Lee continues to be the dominant builder with 49 to its credit and 16 more on order. These tugs have sailed on their own bottoms across the full width of the Pacific Ocean and beyond.
The original owner, PSA Marine, has taken delivery of 16 boats and currently has 16 more on order. G&H Towing operates the largest Z-Tech fleet currently with 28 units in service, with six more under construction.
The Z-Tech design has been a significant success story; a classic example of thinking “outside the box” to solve a basic design problem. The wide acceptance of this novel design has of course led to the inevitable plagiarism, with varying degrees of blatancy, however the original concept stands proudly on its obvious merits.
