Underwater

Jinan, a city of 9.4 million people and the capital of Shandong Province in East China, has made world headlines. Crews working there have completed the monumental task of building the world's largest-diameter underwater shield tunnel.

From fire-breathers to sprinters, climbers and gymnasts, we've seen more than our fair share of impressive quadruped robots. Now the fourth-generation Honey Badger has added underwater walkies to the list of robodog capabilities.

A remarkable semi-submersible ecotourism concept that takes passengers above and below the water has just received a zero-emission boost thanks to a new partnership between Platypus Craft and electric outboard manufacturer Evoy.

A strange sea creature known as the salp reproduces asexually, building long chains of clones. Researchers have now decoded the way these long salp chains propel themselves, a finding that could lead to better propulsion systems for underwater vehicles.

If scuba divers use inflatable BCDs (buoyancy control devices), why don't underwater robots? Well, an experimental new one does, and the technology is said to be much more energy-efficient than traditional methods of moving up and down in the water.

Israeli company BaroMar is preparing to test a clever new angle on grid-level energy storage, which it says will be the cheapest way to stabilize renewable grids over longer time scales. This innovative system lets water do the work.

Penguins are fast, fantastic swimmers, so why not make an underwater robot inspired by them? That's just what German underwater tech company EvoLogics has done, with its new-and-improved Quadroin AUV (autonomous underwater vehicle).

Because GPS doesn't work underwater, divers usually can't track their real-time position on a digital map. The new Diver Navigation System (DNS) gets around that problem, however, using both floating and wearable acoustic transponders.

A new underwater robot can swim through the water with fins, and walk or crawl along the bottom when necessary. These capabilities could really give it a leg up – pun fully intended – at outperforming its traditional thruster-powered counterparts.

Northrop Grumman introduces its first completed prototype Manta Ray Uncrewed Underwater Vehicle that it is developing for DARPA. The extra-large submarine glider is designed to carry out long-range undersea missions without human assistance.

Unlike most other ROVs, the Boxfish Luna is designed specifically for underwater filmmaking. It records video at a resolution of 8K/30fps and can descend as deep as 1,000 m (3,281 ft) – so all you giant squids out there, get ready for your close-up.

Scientists are using UV-emitting glass to keep problematic undersea biofilms at bay. The technology may find use in applications such as underwater viewing ports and camera lenses, and perhaps even one day the hulls of ships.