Taiwan’s new home-grown submarine is a massive headache for China

The new Taiwanese submarine Hai Kun
The new Taiwanese submarine Hai Kun - Chiang Ying-ying/AP

On 28 September, Taiwan launched its first domestically built submarine. Named the Hai Kun, it is a diesel-electric submarine (SSK) that looks to be based on the Japanese Soryu class with some design features carried over from Taiwan’s two Dutch built SSKs. Indications are that this is the first of eight to be built at a total cost of around 10 billion US dollars.

As a weapon system, it is almost perfect for what Taiwan needs. Cleverly combining ‘new’ with ‘tried and tested’ equipment, it is highly likely that these will be effective submarines from the off.

SSKs lack the legs of their nuclear powered brethren but also the crippling price tag and complex supporting infrastructure. Given the ranges at which they will be needed, i.e. inside the first island chain, nuclear propulsion would have been excessive. Taiwan is also developing autonomous underwater vehicles (AUVs) in the form of the Seawolf 400 AUV. Together, this is smart procurement.

Submarines have five main tasks: anti-submarine warfare, anti-surface warfare, intelligence gathering, strike and special forces insertion. I’m not including those designed to fire nuclear missiles.

The first task; operating against well run nuclear submarines will undoubtedly be their greatest challenge. China has nine nuclear attack subs and six nuclear-missile ones. I spent some time in one of the Royal Navy’s (then new) SSKs in the early 90s when they had just returned from exercising against the US Navy’s newest nuclear submarine. Despite the endurance and speed limitations of an SSK, they achieved a number of ‘kills’, so it can be done.

The presence of opposing SSKs will make it much harder for the Chinese to operate their ballistic missile submarines with impunity. Ten billion dollars is not a lot of money if it forces someone to change the way they operate their strategic deterrent.

When running on batteries, SSKs are hard to detect. With the Japanese involved in the design, it’s likely that this boat will have the latest lithium-ion batteries whose endurance can outmatch that of air-independent alternatives. Nevertheless, Taiwanese boats will still have to recharge eventually and to do this an SSK must come to periscope depth and put a snort mast above the surface so that it can run the diesels that then recharge the batteries. This increases the sub’s acoustic, radar, infra-red and visual signatures for the duration of the snort, which can be quite a long time. This is an SSK’s Achilles Heel and it’s a big one.

I once exercised against a Royal Navy nuclear submarine that was tasked to simulate an SSK and so had to come to periscope depth and snort at regular intervals. Normally submariners just cheat when constrained like this, go deep and slink away. To give that captain his due, he played the game and we got our share of kills that week. In other words, SSKs are not a panacea, but if they’re well operated and can go for long periods between snorts, they can be very effective.

As an anti-surface platform it will be most capable. An undetected SSK can run amok in a busy shipping situation, hiding under other ships and picking targets off almost at will. The Mk 48 heavyweight torpedo this one is armed with will ruin your day no matter how large you are. As a deterrent, this boat will be worth every penny: a Chinese invasion force trying to get across the Taiwan Strait would be torn to pieces if SSKs were operating beneath it.

The Hai Kun also has a variant of the sub-Harpoon anti-surface missile. Harpoon is an old system now and has gathered something of a reputation for being slow, inaccurate and easy to shoot down. Then two Neptune missiles (modernised Harpoons) hit and sank the Russian cruiser Moskva in the Black Sea and suddenly everyone started taking it seriously again. The point is, the range rings you have to put on a harpoon equipped submarine – and ideally stay out of – affect your planning. So once again, they work without even being fired.

As an intelligence gathering platform SSKs will be invaluable. A diesel submarine’s ability to operate in shallower water than their nuclear counterparts make them effective at nosing into tight spots and hoovering up sensitive information. They are also expert at gathering intelligence information from ‘enemy’ warships. Chinese surface and subsurface assets will need to go to some length to make sure they’re not being tailed whenever they sail. Again, the subs are doing useful work in this regard whether they’re there or not.

At this stage it doesn’t appear that this boat has either a land strike or a bespoke special forces insertion capability. It’s perfectly possible that these could appear over time or in later builds.

As a tool of influence and deterrence, this is exactly what Taiwan requires. The new SSK uses a sensible blend of modern and well established technology so it is likely to work well from the off. In many respects it is the exact opposite of the ageing, noisy and poorly designed North Korean diesel submarine launched earlier this month.

The Hai Kun’s appearance is also a testament to the number of countries willing to help. The US was front and centre; the torpedoes, missiles, combat system, periscope and sonars all came from there. The hull form shows clear Japanese influence and the propulsion chain is likely to be theirs but the UK, Australia, South Korea, India, Spain and Canada all helped. This must send a powerful message to China on its own.

Japan, South Korea, Vietnam, Indonesia, Singapore and Malaysia all operate submarines in the region already. The Philippines are considering buying some. The US and the UK send nuclear-powered attack submarines there and the Aukus trilateral security pact among the US, Australia and the UK will see more of this. The waterspace management required to keep these boats safe from each other will force a level of cooperation between respective navies that again, will provide a strong message.

China seems hell-bent on converting the South China Sea into a Chinese lake with the number of illegal incursions into other people’s water and air space and aggressive activities increasing daily. How long will it be before anyone daring to transit the Taiwan Strait is met by something more than just indignant rage? Interestingly, the Royal Navy elected not to send HMS Queen Elizabeth through the Strait in 2021 – some would argue that this means Chinese policy is working and the Strait is closing. No matter one’s view on that, it is hard to imagine a more effective weapon for deterring escalation in this area, or dealing with it if the deterrence fails, than a fleet of well-run SSKs.

China has naturally responded already, saying that these submarines pose no threat. Anyone who has spent any time on the bridge of a warship trying to detect one will know that simply isn’t true. In no way have these boats rectified the imbalance of military power in the South China Sea and surrounding waters. But they will cause a serious headache for the Chinese forces, especially the staff officers tasking with preparing plans for invasion of Taiwan.

Tom Sharpe is a former Royal Navy frigate captain with operational experience of anti-submarine warfare

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