There are also a couple of Chinese articles that you can find here and here.
Basically, we can gather the following from these articles:
- They sent out Haixun-31, the largest and most capable Chinese patrol boat, in this 5 day mission sailing through 17,000 nm.
- Haixun-31's length is 112.8 m, beam is 13.8 m and draft is 4.38 m, the displacement is 3000 tonnes. The maximum speed is over 22 knots and it has a range of 6000 nm at 18 knots. It also has 40 days of endurance.
- It's the only Chinese patrol boat with a helipad, a hangar and a flight control tower.
- They also brought out Haixun-111, Haixun-113 and 60 other small patrol boats.
- What's interesting is that they sailed in the East Sea around Chunxiao gas field. This is significant because it's the major dispute between China/Japan in gas exploration.
So, to give you guys an idea of how large the patrol boats are, I'm posting a picture of Haixun-31 and a picture of the small boat.
We know about the deal recently signed between Japan and China on exploration for Chunxiao, but this exercise may have been planned before that agreement. Anyhow, I don't think Japan will appreciate this one too much.