Instead of sending human divers underwater, Triton built a giant yellow submarine called the Sawfish — a 5,500-pound unmanned logging device capable of finding, chopping, and floating trees weighing up to 200 pounds to the surface from deep underwater. When pictures of the Sawfish circulated the blogosphere in 2006, three years after its initial deployment, the sub was harvesting softwood on the west coast of Canada. It has since increased its fleet to four, doubled each machine's lifting power, and expanded its mission to underwater hardwood forests in tropical reservoirs in Southeast Asia, South America, and Africa. Join me and Jim Hahurst, Triton's VP of Marketing, for a photo tour of how the new Sawfish works.
Guided by sonar, video cameras, and GPS, the Sawfish dives down under the surface and finds forests to harvest.
Once it finds the tree, the Sawfish grabs onto the bark with its grapples, which are like giant arms. It inserts a rolled up airbag that bolts onto the tree. Compressed air inflates the airbag. The saw on the Sawfish then cuts the trunk just below the airbag and stays there as the usable part of the tree shoots up to the surface. Then it moves on to the next one. The new Sawfish is capable of cutting and floating up 50 trees per dive.
When the airbags surface, a boat corals the floating trees and pulls them over to a barge area, where they are then transferred to a tugboat that takes them to shore for processing.
These photos were taken at a recent Triton mission in Kenyir Lake in Malaysia. "We got an invitation from the government to do this," Hahurst tells me. "Kenyir Lake had divers for underwater logging in the past, but they were keen to try out safer, more environmentally sound tech." The government gets a royalty and stumpage, but Triton gets full ownership of the logs.
There are about 300 million trees underwater, all of them lying still in a deep freeze, inert because the lack of air prevents them from sequestering carbon. "By putting these trees on the market, we potentially displace land-based logging," Hayhurst says. "There are 45,000 major dam reservations in the world, and we've identified the top 20 opportunities. This is kind of like mining, really — we know where the diamonds are."
Published 5:00 am Wed, Oct 14, 2009
Environment, Green, Technology