2006 - Tractor of the Year: Foss “Dolphin” Class

Award Basis: Each year Towing Solutions recognizes a tractor design (Voith Schneider, Z-drive, ASD, etc) that, in our opinion, significantly improves:

  • that type of tractor’s overall performance,

  • the safety of the crew, or

  • the overall flexibility in meeting a specific port’s requirements. 

As it is not our intention to give away the trade secrets that designers and operating companies have worked hard to develop, the salient features of the winning design will be described but pictures and/or line drawings will, in most cases, not be provided on this web site.  Parties interested in the design for their application are encouraged to contact either the designer or operating company directly.

For 2006 Towing Solutions is proud to award our Tractor of the Year award to the 5,080 Hp. “reverse tractor” (ASD) Dolphin Class designed by Robert Allan Ltd. The boat is owned and operated by Foss Maritime Co. of Seattle, WA.

When Foss Maritime considered adding more tractors to their fleet, they first evaluated the vessels in their current fleet in an attempt to identify additional potential towing requirements in the various Ports that they serve. They quickly recognized that the twin 8,000 Hp Voith Schneider true tractors that they have in Puget Sound more than met that areas high speed escort needs. In San Francisco they also have twin 6,250 Hp. Z-Drive reverse tractors (Foss refers to them as ASDs) that also more than meet the escorting requirements of that Port. However they did realize that in all of these Ports there was a common request from the pilots for high horsepower boats of high maneuverability that were small enough to easily work in tight slips.

To address this requirement, Foss turned to Robert Allan of Vancouver, BC whose earlier “compact” tug design had been successfully operating in Hawaii. The 4,730 Hp. MIKIOI had been delivered in 2004 but had been delivered as a day boat. As most of Foss’ West Coast ship assist tugs are manned 24 hours a day, Foss worked with Robert Allan Ltd. and was able to install twin staterooms in the forepeak of the boat to accommodate this requirement.

Towing Solutions has selected this design as our tug of the year as it takes advantage of the high bollard pull that can be delivered in a small package using Z-Drives. Rather than build another boat in the 92’ - 105’ class as had many of their competitors, Foss elected to build the boat as small as reasonably possible. This not only gives the pilots the small highly maneuverable boat that they want for narrow slips and tight quarters, but it substantially reduces the construction costs for the boat giving them a economic advantage over their competitors. Finally Foss and Robert Allan designed the boat with enough beam (stability) to allow this “reverse tractor” (or “ASD”) to conduct all of the escorting maneuvers that a pilot might ask of them at modest speeds (seven knots and below). For this unique and clever design we award Foss’ Dolphin Class our Tractor of the Year Award for 2006.

Robert Allan has taken the Voith Schneider tractor another step forward with a very dramatic underwater hull shape that is significantly different from the typical double ended “bathtub” shape of traditional Voith hulls.

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