On August 22, the Panama-flagged bulk carrier MV Ocean Winner sank in the Bay of Bengal, roughly 230 nautical miles off the coast of Odisha. The carrier had departed Odisha’s Paradip port carrying 72,100 tonnes of iron ore.The carrier issued a distress alert on Saturday morning from about 378 nautical miles (1 nautical mile equals 1.852 km) east of Visakhapatnam. The Maritime Rescue Coordination Centre in Port Blair was alerted on Saturday that communications with the vessel had ceased. At the same time, it also received a search and rescue request from Victory Star Group Co Ltd., the company associated with the ship.Of the ship’s 24 crew members, only two (both Chinese nationals) have been rescued despite coordinated efforts from the Indian Coast Guard, the Navy, and Beijing’s Maritime Rescue Coordination Centre.Where does a ship’s distress call go in the case of a potential wreck, and how do different maritime bodies coordinate during rescue missions? What does international (and domestic) law say about such exercises? What allows for trans-national rescue operations? We explain.How is a ship’s distress signal addressed?Under international law, a nation’s territorial waters extend up to 12 nautical miles (approximately 22 km) from its coast (or a baseline). Every coastal State is also entitled to claim an exclusive economic zone up to a maximum distance of 200 nautical miles from the same baseline, though it cannot exercise its sovereignty within this extended zone.When the Ocean Winner sank 230 nautical miles from the coastline, it was in international waters. Despite that, the area still falls under India’s “search and rescue region”. MV Ocean Winner’s last recorded AIS location and the proposed route the cargo carrier was on towards Singapore (credit: Marinetraffic.com)When facing imminent danger, vessels rely on the Global Maritime Distress and Safety System — a communications network developed by the International Maritime Organisation which ensures that vessels can alert shore authorities and other ships through an automatic emergency response.Story continues below this adWithin this system, the primary method of alert is through Digital Selective Calling. Such alerts automatically transmit the vessel’s nine-digit identity number which is linked to the ship’s radio equipment. The alert must, however, be triggered by the crew.Ships are also equipped with an Emergency Position-Indicating Radio Beacon. This is a a beacon designed to float free from a sinking ship and activate once in contact with water. The MV Ocean Winner’s distress alert was picked up by the Maritime Rescue Coordination Centre in Port Blair.India’s search and rescue responsibilities span 4.6 million sq km in the Indian Ocean. This area is formally designated as the Indian Search and Rescue Region. This region is double the size of the exclusive economic zone, which covers an approximate area of 2.3 million sq km.The overarching authority for this vast expanse is India’s National Maritime Search and Rescue Coordinating Authority. The Director-General of the Indian Coast Guard heads this authority.Story continues below this adBoth seas — the Arabian sea on the West and the Bay of Bengal in the East — along with the Indian Ocean are high-traffic areas. In order to ensure rapid response, the Indian search and rescue region is broken up into three zones, each of which is overseen by a major Maritime Rescue Coordination Centre. They are:MRCC Mumbai: Western Seaboard and the Arabian Sea to the WestMRCC Chennai: Eastern Seaboard and the Bay of Bengal to the EastMRCC Port Blair: Now known as MRCC Sri Vijaya Puram. It oversees the area around the Andaman and Nicobar region across a nine lakh kilometre square area. It is from this centre that the Indian Navy’s P-8I aircraft was redeployed from a routine surveillance sortie in the Bay of Bengal to aid with the efforts.Story continues below this adThe Indian Navy’s Boeing P8I Long Range Maritime Patrol Aircraft. India was the first international customer for the Boeing P-8 series (Wikimedia Commons)In addition to these three main command centers, there are 36 Maritime Rescue Sub-Centres that operate locally under the main hubs. When an Maritime Rescue Coordination Centre receives a distress alert, a qualified official assumes the role of search-and-rescue mission coordinator.The coordinator is tasked with making key decisions to coordinate efforts on a timeline. They can marshall Coast Guard search and rescue units, request official Naval aerial assistance (like the P-81 aircraft redeployed for reconnaissance) and ensure commercial vessels in close proximity alter their course to provide required assistance.The inclusion of Chinese rescue vesselsBoth members of the crew safely rescued from the MV Ocean Winner were Chinese nationals. Of the 24 crew, 20 were Chinese nationals, three members were from Myanmar and one from Bangladesh.On August 25, the Chinese government officially deployed two vessels to directly enter the search area in the Bay of Bengal. This deployment was meant to augment the existing SAR operation and was jointly announced by the Indian Coast Guard and Chinese authorities.Story continues below this adDuring a search operation conducted by the Coast Guard for missing crew members of the Panama-flagged bulk carrier. (Indian Coast Guard via PTI Photo)The presence of Beijing’s MRCC alongside Indian forces is in compliance with international maritime law.The framework that ensures that deep-sea rescue efforts are collaborative enterprises comprises the following:The Search and Rescue (SAR) Convention: The SAR Convention was adopted in April 1979 and came into force in June 1985. The aim of the convention is to ensure a standard operating procedure for search and rescue operations worldwide. Following the convention, the world’s oceans were divided into 13 search-and-rescue areas. Chapter 3 of the convention requires neighbouring states to pool resources and authorise immediate entry into their territorial waters for foreign rescue units responding to a crisis.The International Convention for the Safety of Life at Sea (SOLAS): SOLAS mandates that the master of any ship at sea is bound to proceed with full speed towards the distress signal received. This obligation is applicable around the world, without considering the nationality or circumstances of the distressed crew. Chapter V, Regulation 33 titled ‘Distress Situations’ lays down the word of law.Story continues below this adThe United Nations Convention on the Law of the Sea (UNCLOS): UNCLOS was opened to signatories in 1982 and officially entered into force in 1994. It is widely referred to as the ‘Constitution of the Oceans’. Article 98 says that every coastal State must ensure the promotion of an established and operational search-and-rescue service. It also mandates that ship captains help anyone at danger in the sea and then should the circumstances arise, States must cooperate with regional neighbours through mutual arrangements.