State of the art deep-sea simulator tests marine technology

WOODS HOLE, Massachusetts (AP) — Imagine the weight of three SUVs stacked on a big toe. That’s the pressure level simulated by the Woods Hole Oceanographic Institution’s (WHOI) new vessel, which is giving the ocean science nonprofit organization and the region’s scientific community a state-of-the-art way to test the performance of marine technology at, and beyond, the deepest reaches of the ocean.

The pressure vessel is the fifth in a series owned by WHOI in its history and is replacing what is called PV3, a 50-year-old behemoth inherited from the Navy that has been used to test everything from sensors to ceramic housings to the high-tech foam that provides Alvin, WHOI’s famed deep-sea submersible, its buoyancy. PV3 is at the end of its lifespan and, while it is designed to simulate depths up to 20,000 pounds per square inch like its newer cousin, it is no longer safe to do so, said marine mechanic Brian Durante, who works at the pressure testing facility.

“It’s just about as old as I am,” Durante said.

Whereas PV3 is run by hand-cranking pressure valves, the new testing chamber, PV5, is fully automated and can run 24/7, said Carl Kaiser, the AUV operations manager at the National Deep Submergence Facility at WHOI.

“It can run more precisely, much longer and run more detailed and thorough tests,” Kaiser said, speaking to Cape Cod Times via satellite phone from the research vessel Atlantis.

“It can accommodate a much higher capacity for both WHOI and local marine technology businesses who need its capabilities.”

The pressure vessel was built in Norway and, overall, is a much sleeker device than PV3. The older vessel’s cap weighs 3,200 pounds, for example, and has to be hauled off the body via an overhead crane. The same work is necessary to remove the lid from PV5, but the cap weighs only 550 pounds; instead of being screwed into the base, it is kept in place by two yokes mounted to the floor that, after the vessel slides underneath them, keep it in place during the test.

PV5 can also accommodate a video camera and audio recording equipment to provide engineers even more detail about their device’s performance at deep depths, said Christopher Griner, senior engineering assistant at the pressure test facility.

The vessel can simulate the pressure at the deepest known part of the ocean – the Mariana Trench in the western Pacific Ocean, nearly 11,000 meters deep – and then some, to allow for engineering devices with extra protection, Kaiser said.

The device and the expanded facility now housing it off Challenger Drive were funded in part by a five-year, $5 million matching grant awarded to WHOI in 2014 by the Massachusetts Technology Collaborative’s Collaborative Research Marketing Grant Program. The program has funded the DunkWorks rapid prototyping facility at WHOI’s Center for Marine Robotics and will fund an indoor test tank facility, Kaiser said.

The construction of the new space for the pressure vessel was a major undertaking; the precision needed in the floor, for example, allowed only a 2-millimeter variance to keep the vessel upright and allow for a smooth movement in and out of the yoke arms, Durante said.

Several local companies took part in the construction project. Noah Greenberg Associates Architects of Falmouth designed the facility; structural engineering work was done by Coastal Engineering of Orleans and was managed by Delphi Construction from its Mashpee office, according to a statement from Delphi.

“We needed a crane to lift (the pressure vessel) in, it needed to be located in a pit, we needed water filtration systems and large volumes of compressed air, pumps, monitoring equipment,” Kaiser said. “It’s a large addition.”

Information from: Cape Cod Times