Bainbridge firm's underwater fish cages like suspension bridges

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Wednesday, February 22, 2006

Bainbridge firm's underwater fish cages like suspension bridges

By HSIAO-CHING CHOU
P-I FOOD EDITOR

A suspension bridge in the round. That's basically what local engineers came up with when they designed the "Sea Station" -- an underwater fish cage that's used by aquaculture companies around the world.

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- Photo gallery
- Multimedia tour of the farm (Flash)

"If you look at all the largest bridges out there, they're all suspension bridges," explained Langley Gace, engineer and aquaculture manager at Oceanspar on Bainbridge Island. "And a suspension bridge consists of columns, a roadway and spoke lines."

A Sea Station has a column (the spar), a roadway (the rim) and spoke lines (the rope or seams that connect the net pieces). The structure resembles two cones stacked base to base, or an extruded bicycle wheel. It provides the maximum capacity without sacrificing stability.

"You can scale it up easily and efficiently," Gace said.

This cage design has set Oceanspar apart in the aquaculture industry for several reasons. The net, for one, is made of Dyneema, a material used in bulletproof vests. Also, the net is machine-braided instead of knotted. A knot, which bends the rope, actually weakens the structure by 50 percent. When the fibers are braided, they remain strong.

"And Dyneema, diameter for diameter, is stronger than steel," Gace said.


		Joshua Trujillo / P-I
	A massive loom weaves fiber into netting at Net Systems. Its Sea Stations are in use in Hawaii where Kona Kampachi is grown.

Oceanspar operates in concert with Net Systems, which specializes in making commercial fishing nets out of Dyneema. Even though the nets cost about $52 per pound (versus $10 to $15 per pound for a standard net), there currently is a four-month wait.

Net Systems began researching and developing aquaculture technology in the late '80s. In the mid-'90s, when the company was bought out by Nichimo in Japan, the original owners held on to the aquaculture division, naming it Oceanspar. It is run out of the Net Systems headquarters on Bainbridge.

Oceanspar offers several cage designs, but the Sea Station is the most unusual.

Sea Stations, of which there are 30 scattered around the world, are made of triangular pieces of Dyneema net that are cut and hung (or attached) by hand. Each cage costs from $110,000 to $170,000, depending on the model. It takes several months to build Sea Station pieces at the workshop on Bainbridge. Then, the parts are shipped and assembled on site.

Kona Blue, which grows Kona Kampachi in Sea Stations submerged off the shore of Kona, Hawaii, has collaborated with Oceanspar to create a cage that can be flipped under water so that the bottom half can be raised above the surface for cleaning or harvest.

Oceanspar was ahead of its time when it began designing what would become the Sea Station. But the word has spread.

"We have a lot of venture capital interest now," Gace said.