Coast guard–type forces, commonly called “white hulls,” ought to constitute a stabilizing presence compared to regular navy forces (or “grey hulls”), as sea-power theorist Harold Kearsley wrote in Maritime Power and the Twenty-First Century in 1992. “White hulls” do not convey the same overtly militaristic, war-fighting impression as regular naval forces employed for this purpose.

But theory can only go so far when the parties concerned have a different, or even revisionist, interpretation. China, for one, has quashed Kearsley’s idea. The recurring South China Sea incidents are illustrative: no longer are “white hulls” more dovish than their naval counterparts. In some cases, the coast guard can prove to be aggressive while the navy is relatively docile.

http://www.nationalinterest.org/feature/the-south-china-seas-%E2%80%98white-hull%E2%80%99-warfare-15604