 Type 05 is also referred as "South Sea Design" (Nan-Hai Fang-An, 南海方案), a design built by Guangzhou shipyard, tailored specifically for operations in South China Sea.The most important upgrade includes the replacement of the forward twin 37 mm gun with a single 85 mm gun, and the replacement of manual loading of the ammunition by electrical ones.The water heater and heating system were deleted and replaced by air conditioning system.