An unmanned Chinese submersible has bettered its world record by diving one metre deeper into the depths of the western Pacific Ocean, according to the machine’s developer. The Chinese Academy of Sciences Shenyang Institute of Automation said on Monday that the Haidou 1 sub went down 10,908 metres (35,787 feet) to the sea bed of the Challenger Deep in the Mariana Trench during an expedition. It did not specify when the record was broken. The dive not only improved on the world mark set by the Haidou last year, it stayed down on the sea bed for 10 hours – two hours longer than its previous longest foray on the ocean floor, according to the institute. The Challenger Deep is the deepest area in the Mariana Trench and also the deepest known point of the Earth’s surface, with a pressure about 1,100 times that at sea level. The institute said that part of the submersible’s mission this time was to do an acoustic survey of the area. “For the first time in the world, Haidou 1 completed wide-range and full-coverage acoustic detection in the western depression of the Challenger Deep,” it said. “Haidou 1 … filled gaps in scientific exploration of waters at more than 10,000 metres deep.” The institute said the vessel made many trips beyond 10,000 metres to do research, proving that it could operate in a continuous, stable and reliable manner. It said Haidou 1 was particularly strong at spotting target objects, reading the terrain of the sea bed and doing real-time live video broadcasts. The institute also released high-definition images captured by the submersible, including pictures of ocean creatures and topography of the sea bed.