difference between pump pipe and dredge line

Taiwanese military officials and Western analysts say China’s gray-zone tactics are meant to drain the resources and erode the will of the island’s armed forces - and make such harassment so routine that the world grows inured to it. Taiwan has been scrambling military aircraft on an almost daily basis to head off the threat, placing an onerous burden on its air force. The most dramatic: In recent months, the People’s Liberation Army, China’s military, has been dispatching warplanes in menacing forays toward the island. China, which claims democratically-governed Taiwan as its own territory, has been using other irregular tactics to wear down the island of 23 million. Sand is just part of the gray-zone campaign. “You dredge for sand on the one hand, but if you can also put pressure on Taiwan, then that’s great, too.”

The dredging is a “gray-zone strategy with Chinese characteristics,” said Su Tzu-yun, an associate research fellow at Taiwan’s top military think tank, the Institute for National Defense and Security Research.

In Matsu, there were also many Chinese vessels that sailed close to Taiwanese waters without actually entering, forcing the coast guard to be on constant alert.

Difference between pump pipe and dredge line