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November 2011www.marinelink.com 49cluding the Campbell. These are all planned to be retrofitted as hybrids. Foss is currently going through EPA certification for the Carolyn Dorothy. Having the conventional sister tugs has helped compare apples to apples, as far as the true fuel and emissions reductionsrealized, Faber said. ?We?ve met or ex- ceeded the original estimates for emis-sions reductions and fuel savings on the Carolyn Dorothy,? he confirmed. Opera- tional results from the pilot hybrid show that the main diesel engines have been used just 1% of the time and the genera- tor engines are used 65 to 85% of thetime. Faber said the entire Dolphin class should be retrofitted in five to seven years, ?unless demand changes,? in which case ?we could do it in threeyears.? Retrofitting one vessel takes about two months, depending on how it fits in with other projects going on in the yard. ?We look at what every craft does and match the hybrid system to those re- quirements,? he said. ?We know exactly what the duty cycle is, the frequency she spends at what band of power. We work backwards and come up with the right sized generator which drives the propul- sion unit in hybrid mode.? There are three components of the hy- brid system: the main engines, the gener- ator engines and the batteries. Having been built from scratch, the Carolyn Dorothy was designed with smaller en- gines, but the retrofitted tugs will be keeping their larger engines. ?The real challenge on the retrofits is finding the extra space for the generator engines and batteries,? Faber said. OTHER TECHNOLOGICAL ALTERNATIVES? ?Hybrid technology lends itself to har- bor craft with the intermittent cycles,? Faber said. But what about other ways to reduce the carbon footprints of work boats? (Photos courtesy Foss Maritime) (Photos courtesy Foss Maritime) LeftSusan Hayman, Foss Vice President, Environmental and Governmental Affairs, with one of the Campbell Foss' new generators. Right:?Now and in the future, we believe the companies best positioned to compete for work will be those with the best environmental and safety records,? said Foss President and CEO, Gary Faber MR Nov.11 # 6 (42-49):MR Template 10/28/2011 12:24 PM Page 49