SMALL BOAT OPERATIONS IN ARCTIC ALASKA

Erik Reimnitz

Photo of R/V Karluk refueling in the Arctic Alaska.

The discovery of oil under the low coastal plain of Arctic Alaska brought an urgency for the Federal Government to study the adjacent shallow shelf, which is covered by sea ice much of the year. Normal oceanographic vessels cannot operate in these waters less than 20 m deep, where much early petroleum exploitation could occur. In response, the USGS developed a small-boat survey program with shallow-penetrating seismic systems, side-scanning sonar, sampling, and diving capabilities in order to study the inner shelf. A 40-ft-long, diesel- powered personnel carrier was acquired from the Navy for a crew of four to run seismic surveys. The boat, the R/V Loon, was equipped with two generators for seismic and sonar systems, a sampling boom, and living quarters for four. The boat was brought to the Arctic by railroad to Great Slave Lake, Canada, and then via the Mackenzie River to the Beaufort Sea. There the Loon was used for surveys during the summers of 1970 through 1973 from Prudhoe Bay, where it was winterized on land.

After proving that cautious operation around pack-ice floes with a fiberglass hull was feasible, the USGS provided support to the Arctic project to build a suitable small, shallow-draft fiberglass boat for a crew of four; the new boat was christened the R/V Karluk. Construction of this 42-ft vessel started at a Seattle boat yard in 1974, using the hull of a rugged seining boat with a tunnel drive, giving it a draft of about 1 m. The hull was strengthened below the waterline for cruising among ice floes. Three diesel engines were cooled through keel coolers, allowing operation through freezing storms that generate frazil ice in the sea. Built into the hull was a sea chest holding transducers for depth sounding and shallow seismic work. Below the work deck were two diesel generators (7.5 and 15 kW) to power the electronics. The main engine, generators, and galley stove were fed from 925-gallon fuel tanks, adequate to cruise from Prudhoe Bay to as far as Nome, Alaska. The Karluk usually towed or carried on deck a 15-ft outboard-powered skiff. For safety, it also carried a 6-man inflatable boat, an emergency beacon, and an engine room fire-prevention system. The boat controls were next to a gyrocompass in the wheel house, and also on the cabin top. It carried a diving compressor. Various hydro acoustic systems have been used from the Karluk. The side-scan fish was usually towed from deck, but for waters only 1 m deep it was suspended from a special bowsprit. A catamaran for seismic transducers usually was towed from one of the stabilizer booms alongside. The boat was successfully used with a 1-ton vibro-corer deployed over the side. The Karluk operated in water depths as shallow as 1 meter. Fueling was often done directly from the beach (see the photograph), as there were usually no docking facilities.

The R/V Karluk ran surveys mainly in the Arctic, where seasons are short and the sea freezes completely in October. It operated from the Yukon River in Alaska to the Mackenzie Delta in Canada. The boat has been winterized in Nome, Kotzebue, and Prudhoe Bay, Alaska, and in Toktoyaktuk, Canada. When funding from NOAA’s Outer Continental Shelf Environmental Assessment Program (OCSEAP) ended, the Karluk was returned to its Seattle home in 1989. Its activities are documented in a long record of Open File Reports and scientific publications.

For further specifications and pictures see http://walrus.wr.usgs.gov/infobank/programs/html/karluk/karluk.html

For areas where the Karluk worked see http://walrus.wr.usgs.gov/infobank/programs/html/platforms/html/Karluk.html

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