Observe, the submarine in the water appears to be a Type 39A, also known as Yuan class, but what do you make of that submarine in dry dock? Nope, not a Type 39, or a Type 39A. In other words, this rather rough photo managed to catch a new Type 39 mod before it hit the water.
What we are observing is different in the area around the sail. It looks as if they have adjusted the design a bit on top to accommodate something new. This makes some sense, it is a lot easier to adjust the top of a submarine hull than to add a plug, in many ways this is similar to how the Chinese used the Type 93 to build the Type 94 a SSBN, simply adding a small plug and building up rather than adjusting to a large degree the hull form. Our Russian sub guy had the following observation on this new photo.
"It appears to be a hyrdodynamic change specific to the outer hull, but with a slight length/width increase this could be some sort of modification to support a new propulsion system. China supposedly had early problems with the first AIP on the Yuan, this design change could reflect an evolution. If they changed the propulsion system it would probably require a change to the inner hull, meaning this submarine might end up with a new designation. The Song and Yuan were both Type39 because the inner hull was the same."
For those not as familiar with Chinese submarine design, let me explain his comments a bit. Like the Russians, the Chinese build their submarines with 2 hulls. The Song class, or Type 39, and the Yuan class, or Type 39A, are suggested to have very similar designs for their inner hulls. Only the hull form of the outer hull differentiates the two classes, not including any equipment modifications. The Chinese have in fact created two different classes of conventional submarines, the Type 39 Song class, and the Type 39A Yuan class, by simply adjusting the hydrodynamics of the outer hull. Adjusting outer hull form is a way to maintain some consistency with proven designs for the inner hull while accommodating new technologies with small adjustments to the outer hull, like what we are seeing here.
The Chinese BBS where we originally saw this photo claimed this new submarine was longer, wider, and had more power. If that is true, and we wouldn't know without a photograph from a different angle, that would fit the description above. I also asked Gary over at Defense Talk what he thought, and short of telling me nothing like a true pro, he mentioned he thinks it is probably done to make an AIP mod. He noted that it makes a lot more sense to modify the top than to mess around with the balance of the hull, something we have heard virtually every professional highlight regarding this picture.
Is this the first photo of a Type 39B? Time will tell, but it definitely appears to be a new mod for the Type 39s being produced at Wuhan. For us, this photo is yet more evidence that the open source remains the best source for public dissemination of submarine evolutions taking place in China.
Credit to Feng for the first photo, who himself is blogging the photo a bit and is likely to add more as the discussions evolve. I know a lot of you sub guys are a whole lot better at this than us, so please feel free to add your take to the comments.
Update1: Added the larger original at the bottom, and a link to the picture.