source from :https://www.rivieramm.com/news-content-hub/chinas-first-lng-fuelled-osvs-delivered-71423
COSL, a subsidiary of China National Offshore Oil Corp (CNOOC), took delivery of Haiyang Shiyou 542 and Haiyang Shiyou 547 on 28 May. The two dual-fuel PSVs are specially designed to provide stand-by and rescue, cargo transportation, and external fire-fighting services for China’s offshore oil and gas development.
China State Shipbuilding Corp (CSSC) reported these dual-fuel PSVs are the first of their type to carry four smart systems, including an advanced navigation systems and collision avoidance system.
The two PSVs were part of a series of 12 that ordered three years ago. Each is equipped with Wärtsilä 20DF dual-fuel engines, allowing them to operate on either conventional liquid marine fuels (light fuel oil, heavy fuel oil or biofuel) or LNG.
When operating in gas mode, the Wärtsilä engines are compliant with IMO Tier III regulations without any secondary exhaust gas purification systems. Also, when fuelled by natural gas, the engines emit significantly less sulphur oxides and CO2 emissions than when operating on liquid marine fossil fuels.
Ship intelligence can effectively improve the safety, economy, environmental protection and efficiency of ships, increase ship production efficiency by 15%, and reduce operating costs by 10%. As the first domestic offshore supply vessels to use LNG as fuel, the emission indicators of these ships meet the most stringent international standards, which can reduce CO2 emissions by 20% to 30%, SOx by 100%, NOx by 90%, and PM by 100%.