Yunnan does not really have a sea border, but it has one famous seafaring son: Zhenghe 郑和, a Muslim from Jinning, who in the early 15th century commanded a Chinese fleet in its exploration of the southern seas.
The location of the festival is likely to be Kunyang's Zhenghe Park. The festival was apparently upgraded in 2010 to an 'important' festival and according to http://en.kunming.cn/index/content/2010-06/28/content_2206521.htm the local government is trying to promote it as a local tourism event.