This graphic, courtesy of Xinhua News shows 3 Chinese ships in the Northern search area and 4 Chinese ships in the Southern search area, with the Haixun 01 in the centre, where it picked up the 37.5kHz pings. It's entirely possible the Haixun 01 was transiting the Northern zone to the Southern zone and was looking for pings as she went.
It's been stated that the pings were picked up by simply dropping a hydrophone over the side of the RIB. That's the reason for the surprise.
It's sort of like you throwing in a unbaited fishing line on a quick test of the waters, and suddenly landing a big one.
It's simply not possible to tow a pinger locator with an RIB, the weight of the cable alone would sink it.
There's nothing sly, nor any signs of a totally independent operation by the Chinese. All Xinhua news items refer to Angus Houston of the JACC as the "leader" of the search operation.
For obvious reasons involving language and chain of command, the Chinese are not going to have Angus Houston giving orders directly to every Chinese item of equipment - the area of interest will be indicated to the Chinese and they'll be left to operate as a group, using their regular chain of command.
The major problem is the Chinese news journalists on the Chinese ships and aircraft who will obviously send any news home to China first, in the hope of a "scoop".
Journos operate the same, the world over. Angus Houston has subtly reminded them, that any "breaking news" really needs to go to him, first.
