China’s Submarine Solution for the Taiwan Strait

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Henry Holst, Essay: China’s Submarine Solution for the Taiwan Strait. USNI News, July 8, 2015.
http://news.usni.org/2015/07/08/ ... r-the-taiwan-strait

Quote:

"The Yuan was primarily designed to deal with US forces during a Taiwan contingency and is the only SSK that China is currently producing.

"A trade-off analysis on what little public information is available on the platform suggests the PLAN designed the Yuan to be a small, quiet, slow-moving anti-surface warfare platform. * * * trade-off analysis suggests the Yuan was designed primarily as an anti-ship cruise missile (ASCM) platform capable of hiding submerged for long periods of time in difficult-to-access shallow littorals.

"Japan’s Sōryū 蒼龍-class SSK provides an ideal contrast with the Yuan. The Soryu is 84 meters long, with a draft (height from water line) of 10.3 meters, a beam (width) of 9.1 meters, and a crew of 70. In contrast, the Yuan is 73-75 meters long, with a draft of 5.5 meters, a beam of 8.4 meters, and a crew of 58. Various sources report different submerged displacements for the Yuan. Comparatively, it is far smaller than the Soryu

"The AIP-equipped Yuan and non-AIP Song have extremely analogous dimensions. * * * AIP systems are large and take up internal volume. PLAN naval architects deliberately maintained the Song-class’s size even with the installation of an AIP system. * * * there is no doubt that the inclusion of an AIP system required capability reductions elsewhere in order to maintain the Song’s size.

"There are two advantages to small platform size: shallow operations and cost. * * * Given that SSK’s do not have the speed and longevity to evade quickly once detected, the Yuan’s terrain accessibility is a critical part of its survivability and operational ability.

“Nuclear attack submarines (SSN) like the US Virginia-class (SSN-774) operate with comparatively greater difficulty in this type of terrain. While SSNs have enormous advantages over SSKs, shallow terrain partially limits the SSNs’s primary advantage: diving deep at high speeds after firing and thereby evade detection. Furthermore, maritime geography may circumstantially limit larger submarines physical maneuverability. It is conceivable that an adept PLAN submarine captain (A Chinese Günter Prien) could take advantage the Yuan’s shallow draft and wedge the SSK into a difficult-to-access channel or maritime feature, and thereby forcing higher-technology SSNs to fight on unfavorable terrain

In Yuan, “PLAN’s decision to maintain the Song-class’s double-pressure hull (two hulls: an inner and outer hull, rather than just a single-hull).  For technologically inferior navies like the PLAN, the main benefit to double-hull designs is the additional surface areas where sonar-absorbing, sound-dampening anechoic tiling can be placed. While double-hull designs were used in the past to increase survivability * * * it is extremely unlikely that a double-hull would keep the Yuan operational after being hit with a modern torpedo like the US Mark 48.

“Double hulls come at a significant capability trade-off: they are costly, difficult to repair, and increase platform size, which in turn increases hydrodynamic drag, lowers engine efficiency, cruising range, and therefore longevity. * * * In contrast, single-hull designs are lighter, faster, have a higher internal volume-to-displacement ratio, and yet are less stealthy, given likely PLAN technology (The United States has used single-hulls for decades because of advanced US quieting technology).  The PLAN was clearly willing to accept capability limitations and reduced range and speed in order to improve the Yuan’s stealth. The use of a double-hull reinforces the Yuan’s status as a chokepoint guard, rather than a platform that would use AIP to ‘act like an SSN for a day’ and seek-out targets in blue water.  The PLAN may have accepted this trade-off because the Yuan will primarily use anti-ship cruise missiles rather than torpedoes

“The AIP-equipped French Scorpène and Russian Lada-class submarines, both dimensionally similar to the Yuan, have an export price of $450 million. The larger Japanese Soryu costs around $540 million (That is the sixth Soryu’s cost, which benefited from pre-existing designs and a well-established shipyard: a situation the Yuan shares). The cost of the Yuan is unknown.

“a Virginia-class SSN [costs] ($2.8 billion). While SSK capabilities are in no way comparable to SSNs, such comparatively low-costs directly contribute to the PLAN’s two-to-one undersea platform quantitative advantage vis-à-vis its US counterparts

"Conclusion[:] The Yuan was designed be a small, cost-minimizing, quiet ASCM platform intended to excel at anti-surface warfare [as opposed to anti-submarine warfare (ASW)]. * * * However, such generalized conclusions do not take into account the effectiveness of U.S. missile defense, ASW, C4ISR, space and cyber abilities. In other words, trade-off analysis suggests what the PLA may hope it’s submarine force can achieve tactically, operationally, and strategically; not what it is guaranteed to be capable of.

Note:
(a) Type 039A submarine (NATO reporting name: Yuan-class; In commission 2006- )  Wikipedia
(b) hull classification symbol
https://en.wikipedia.org/wiki/Hull_classification_symbol
(section 3.1.3 Submarine type: “SSK: Hunter-Killer/ASW Submarine (retired [because US does not have this type any more]) * * * SSN: Attack Submarine, Nuclear-powered”)

(c)
(i) Günther Prien
https://en.wikipedia.org/wiki/Günther_Prien
(1908-1941; U-47 went missing on 7 March 1941 while attacking Convoy OB-293 [qv])
(ii) Günther
https://en.wikipedia.org/wiki/Günther

(d) Mark 48 torpedo
https://en.wikipedia.org/wiki/Mark_48_torpedo