Silkworm anti-ship missiles. The Royal Thai Navy received four new Type 053HTs (based on the then-latest Type 053H2) in the early-1990s. Each cost ฿2 billion. Two were modified with rear helicopter decks. The sonar on these ships is SJD-5A, a further development of Echo Type 5 sonars on the same class of ships sold to Egyptian and Bangladesh navies, with VLSIC replacing LSIC. By the mid-1990s, the Thai Navy again ordered two enlarged Type 053 hulls as the F25T Naresuan-class frigates. The general designer of F25T frigate is Mr. Zhu Yingfu (朱英富). The F25Ts were fitted with Western engines and armament, and their construction was supervised by technical advisers from the German ship building industry. Sonars on these F25Ts are SO-7H, which is the Chinese version of French DUBA25. Transfers to the Coast Guard In 2007, the Type 053H frigates "509" and "510" were transferred to the China Coast Guard and refitted as Ocean Patrol Vehicles "1002" and "1003". The superstructure was heavily modified. Armament was reduced to a small cannon forward and heavy machine guns; some of freed space was used to stow small patrol boats and add crew quarters. Transfers to Bangladesh Navy One used Type 053H1 frigate was sold to the Bangladesh Navy as BNS Osman in 1989. She was the first guided missile frigate to enter in service with the Bangladesh Navy. In 2013, two Type 053H2 frigates were transferred to Bangladesh Navy as BNS Abu Bakr and BNS Ali Haider respectively. Transfers to Myanmar In 2012, two Type 053H1 frigates, Anshun (FFG 554) and Jishou (FFG 557) were transferred to Myanmar Navy as UMS Mahar Bandoola (F-21) and UMS Mahar Thiha Thura (F-23) respectively. Incidents On 11 July 2012, a Jianghu-V ship, Dongguan (560), ran aground on a shoal off the coast of the Philippines. The area where the incident occurred, known as Half Moon Shoal (Hasa Hasa Shoal in the Philippines) in the Spratly Islands is 60 miles west of Rizal, Palawan. By 15 July the ship had been refloated and was returning to port with no casualty and only minor damage. Confrontations over territorial disputes in the South China Sea, and particularly the disputed status of the Spratly Islands, have become more frequent in recent years, and caused noticeable friction at the 2012 ASEAN summit in Phnom Penh that was taking place at the same time as the incident. Versions Type 6601 (Chengdu