If the international tug business is down, you couldn't tell it by the turnout at the recent International Tug & Salvage Convention and Exhibition in Vancouver, British Columbia. The ITS convention, which is held every other year in different cities worldwide, was also in Vancouver in 1973.
May's ITS convention was the biggest ever, with 467 delegates, 103 exhibitors and 36 countries represented.
ITS 2010 featured three days of presentations, exhibits, and networking opportunities. Sponsors included Damen , Foss Maritime , MTU , Robert Allan Ltd., Samson , The Shipowners' Club , and SMIT .
The principal business at every ITS convention - and presumably the reason delegates pay almost $3,000 each to attend - is the presentation of the technical papers. Again this year, ITS organizers included a "Green Session," which ran concurrently with a "Casualty Co-operation Session." All together, 32 papers were presented over three days.
A recurrent theme throughout the convention was the environmental impact of tug operations. The trend for what David Gray of Glosten Associates , Seattle, calls "low-polluting tugs" is clearly growing.
W TUG
The first paper, "Innovation in Tug Design," was presented by Wilco van der Linden and Koen Vonk, both with Wärtsilä . Working under the philosophy of "Energy, Environment, Economy," Wärtsilä has developed the W TUG 60 harbor tug and the W TUG 80 offshore tug, both envisioned with either conventional twin, medium-speed engines or "an advanced hybrid version, with twin Wärtsilä 9L20 main engines and a single Wärtsilä 6L20 generating set connected to the thrusters by means of an electrical power intake." The hybrid model also includes a ship's service generator and a frequency transformer
"The electrical input is simply mounted on the reverse side of the thruster as per existing input installations. The target for this hybrid is to be able to transit on a single engine in diesel-electric mode, and then supplement this with the mechanical engines when in assist mode.
"Batteries, dual-fuel engines, and fuel cells allow further emission and efficiency improvements. Even more advanced hybrid tugs can be expected in the near future."
GREEN DESIGN
Andra Papuc of Robert Allan Ltd. discussed a detailed analysis of 11 older British Columbia coastal tugs, which was undertaken in preparation for the development of a new generation of coastal line-haul tugs.
Her report concluded that "the older generation of tugs often had the advantage of being relatively large and low-powered for their size, aspects which contribute to general crew comfort. Economic pressures and the apparent need to maximize power and capacity per size will counter the objective of having a comfortable, sea-kindly and fuel-efficient design. In this age of green technology, there is a lesson here too, that fundamental design issues can be some of the most critical aspects of a 'green' design."
LITHIUM POWER
Brent Perry of Corvus Energy , Richmond, British Columbia, presented a paper on the evolving advantages of lithium-ion battery technology. Perry described the development of small lithium batteries for portable electronics. While successful, these batteries are based on lithium iron phosphate chemistry, which is not suitable for larger power packs. The better alternative is lithium polymer, which is based on nickel manganese cobalt (NMC) chemistry.
According to Perry, NMC lithium polymer technology can "produce cells with the power, energy storage and discharge features that are critical to the success of engineering battery packs that start at 6 kwh and can be scaled to sizes (literally mwh) that actually challenge and offer real alternatives to fossil-fuel power plants. It is ideally suited for high-power marine applications."
HYDROGEN POWER
Capilano Maritime Design , North Vancouver, British Columbia, has developed plans for a prototype hybrid-electric tug that uses hydrogen fuel cells, NMC lithium polymer batteries, and a single diesel generator. The 78' tug would produce 55 metric tons of bollard pull. Chris Mulder presented the paper that describes the project.
"The key to the next generation of hybrids is an all-electrical propulsion system, which provides maximum flexibility for selection of various power sources and fuel types to minimize emissions and improve fuel efficiency," said Mulder.
In Capilano's concept, hydrogen fuel cells would provide a continuous output of 600 kw, which is about 17 percent of full power. "Combined with batteries, this mode can provide 1,250 kw (35 percent power level) for more than one hour," he said.