Why would any Coast Guard need 12KT cutters? CCG wants to patrol the Caribbeans or what?
It's a fair question.
They could need them for extremely long distance patrols or assistance with China's economic needs, or for humanitarian assistance at great distance from China and for long duration, associated with China's economic needs.
The Japanese currently have the two largest Coast Guard Cutters in the world, the latest of which, PLH 32 Akitsushima, was launched in 2012 and commissioned in 2013. She displaces something over 9,300 tons full load and is almost 500 feet long.
[video=youtube;OCHiGMUm2dE]http://www.youtube.com/watch?v=OCHiGMUm2dE[/video]
PLH 32 Akitsushima. Watch this in full screen resolution
She is fitted with the OPS-14 2D air search radar (Japanese version of the US AN/SPS-49), two Oerlikon 35 mm twin cannons, one M61 Vulcan cannon, and two 40mm cannons. She can carry two medium sized helos in her twin hangers and has a large, oversized landing pad aft on the vessel.
These vessels were desinged specifically to be able to transit from Japan to Europe without refueling while escorting plutonium shipments, and they are also used for anti-piracy, anti-terrorism, and other missions requiring long transit times and long duration on station.
They are really large destroyer sized vessels without all of the really heavy armament.
If China has a similar need, that's what the vessels will be used for.