Robotic or manned submersibles, regardless of their sizes, could use anchors that are able to embed themselves into the loose soil at the bottom of the oceans. This type of anchors could easily keep the water craft in their desired position, but the effort has always been to find the most advanced and efficient design for the instruments. A possible breakthrough was made by Massachusetts Institute of Technology (MIT) expert Anette (Peko) Hosoi, who turned to nature for inspiration. The best design for the self-embedding anchor was found in one of nature's most effective diggers, the razor clam.

“The best anchoring technology out there is an order or magnitude worse than the clam – most are two or three orders worse,” Hosoi explains. The MIT group the expert leads will present their new design between November 22-24, at the 62nd Annual Meeting of the American Physical Society's (APS) Division of Fluid Dynamics. The meeting will take place at the Minneapolis Convention Center. According to the team, the clams are able to dig into their mudflats at a rate of about one centimeter per second, which is extremely fast.

Clams are bivalves, which means that they have a very basic anatomy. Regardless, they are able to dig themselves into the soils with relative ease. It was precisely this design that the MIT group wanted to replicate in its new anchor. Hosoi reveals that the way the clam goes about embedding itself in the sand is to first push in the material with its “foot” (mixing the sand with the liquid above), and then pushing downwards in a synchronized motion. This basic, two-step approach proved to be extremely efficient and reliable for the animals, so evolution favored it.

The new instrument designed at MIT is a very small, lightweight and energy-efficient robot, which is being operated, and connected to a boat at the same time, via tether. The innovation opens and closes with the help of air pressure from a connected scuba tank nearby. The machine is able to function just as precisely as the real deal, and the team is currently testing it extensively in the mudflats off Cape Cod. All the operations related to handling the robot are being done electronically, the team concludes.