1 / 9The four day-long search for the missing Titan submersible has come to a tragic end. Reports have confirmed the vessel was subject to a catastrophic implosion during its journey towards the shipwreck, which would have killed all five passengers instantly. But why is the missing Titanic sub being referred to as a submersible and not a submarine? Here’s how a submersible is different from a submarine. (Image: AP)
2 / 9What are submersibles? Submersibles are underwater robots that are deployed from the ship to the sea, where they record and collect information from the ocean’s water column and seafloor for scientific analysis. There are various kinds of submersibles. Some are underwater robots, operated remotely in real time or preprogrammed to cover a pre-decided route. Some other submersibles, like the missing Titan, are capable of transporting people to the depths of the ocean. (Image: Wikimedia Commons)
3 / 9Relative to submarines, submersibles are very small and simply constructed, and are only equipped for short-term dives. The main difference between a submarine and a submersible is that a submarine can leave port and come back under its own power. A submersible has very limited power reserves and cannot launch itself into the ocean, or come back, on its own. It needs a mother ship that can launch it and recover it. (Image: Wikimedia Commons)
4 / 9Submersibles need oxygen supply in tanks. Most submarines, by contrast, can generate their own oxygen, and might stay submerged for a few months at a time. (Image: Wikimedia Commons)
5 / 9Types of submersibles | Human-Occupied Vehicles (HOVs) | HOVs transport a small team of scientists and pilots directly to the seafloor for a limited amount of time. Similar to the other submersibles, HOVs are equipped with tools such as lights, cameras, sensors, manipulator arms, and collection instruments. HOVs are renowned for their contribution to research breakthroughs over the past many years, including the investigation of the RMS Titanic shipwreck. (Image: AP)
6 / 9Remotely Operated Vehicles (ROVs) | ROVs are tethered underwater robots used for research, exploration, and imagery collection. ROVs are tethered to the ship, allowing control signals to be sent and received directly between topside operators and the subsea vehicle. Many ROVs can also collect samples via a manipulator arm operated by a pilot. (Image: Wikimedia Commons)
7 / 9Autonomous Underwater Vehicles (AUVs) | AUVs are independent underwater robots used to explore the ocean. Unlike ROVs, AUVs are untethered from ship, allowing them to complete preplanned missions without direct control from an operator. Once deployed, AUVs operate on their own, guided by a pre-planned route. An AUV collects high-resolution data, which is stored within the vehicle and collected by researchers once the AUV has surfaced. (Image: Wikimedia Commons)
8 / 9The Titan | The submersible was roughly the size of a minivan, with five adults aboard. It was meant to stay submerged for around 10 hours and had a four-day supply of oxygen for its five passengers when it began descent. The sub, which was missing since June 19, sparked a massive search spanning thousands of kilometres across the North Atlantic. (Image: Reuters)
9 / 9On 22 June, an ROV found debris off the bow of the Titanic, the shipwreck that was the intended destination of the expedition. It is believed that the vessel was subject to a “catastrophic implosion” at some point during its voyage towards Titanic.
