One Big Barge
The first of this month saw the final deadline set for the phase-out of single-hull oil tankers and barges in US waters to comply with the Oil Pollution Act of 1990 (OPA '90). Two 296-foot by 60-foot single-hulled oil barges built by Zidell in Portland in 1982, the David 120 and C. F. Starlight, whose careers would otherwise be cut short, found new life when combined as the 296-foot by 124-foot Dioskouroi, transformed, owned and operated by Seattle's Boyer Towing.
The barges could no longer be used for petroleum transport, but were ill-suited for other uses. "They were too narrow and high-sided to use as deck barges," says Boyer Halvorsen, owner and president of Boyer Towing. "On the other hand, the hulls are in perfect condition."
Halvorsen's company purchased the barges and set about combining them. The company originally purchased the twins to combine as a crane barge to provide installation support for a natural gas project in Cook Inlet, Alaska. That project plan changed, and the barges' mission changed as well.
"When the plan called for a crane barge, we were going to cut one side off of each barge and weld them together," Halvorsen says, "But they were in such good shape it seemed a shame to do that."
Along came a contract to move crushed rock from a quarry in Wrangell to Kodiak Island for the lengthening of a runway at the Kodiak airport. "It turned into a great opportunity," Halvorsen says.
The company set about connecting the two barges while they floated at Boyer Towing's facility on Seattle's Duwamish River. The two barges were conjoined, side-by-side, before being towed to Bellingham for final plate installation and out-of-water work. Four feet of width was added to the combined barges during the construction process.
"First we welded corresponding horizontal posts on the two sides to be combined," Halvorsen says. "One of each corresponding post was smaller in diameter, so the two sides would telescope in and out."
Once the dimensions were set, Boyer's employees, under the guidance of James Kreuter at Vanguard Marine, PLLC, who provided engineering services on the project, added four-foot wide frames to the exterior of the hulls, at the same location as the existing frames inside the barges' skins. Each frame was alternated, with one frame being welded to the barge on the port side, the next to the barge on the starboard side, and so on. The workers welded the frames down to the waterline, and once all the frames were in place, each was welded to the other barge to form a complete structure.
"It's actually a stronger connection than it would have been to join them another way," Halvorsen says.
Once Boyer had done all the work they could on the new barge in the water, it was towed to Bellingham, Washington, where Fairhaven Shipyard's Faithful Servant drydock, with a 131-foot beam capacity, was just wide enough to lift the new barge. The frame welding was completed along with the bottom plate installation.
Once the barge was complete, Boyer added a 12-inch thick timber wear deck and put her to work in Alaska, where she made six trips of 850 nautical miles each way between Wrangell and Kodiak.
"The barge tows really well," says Halvorsen. "With the 4,000-horsepower Billie H. towing the barge it made 9 knots empty and 7.1 knots loaded with 11,000 tons of rock."
The new vessel is classed ABS Ocean Load Line Deck Cargo Barge and rated for 15,000 short tons of deck cargo. Named Dioskouroi after the twins Castor and Pollux, who were the mythological sons of the Spartan queen Leda and inspired the constellation Gemini. Halvorsen says the barge is a welcome addition to the fleet. "We're glad to be able to offer our customers such a large and stable platform for their special projects."