Taiwan currently has four submarines in its navy. Two are World War II era American diesel-electric subs that entered service months before that war ended in August 1945. These two boats are used only for training and are increasingly difficult and expensive to maintain. Despite that the crews work hard to keep these museum pieces looking good and still operational. Recently Taiwan announced a $19 million effort to refurbish one of their World War II era subs so that it will remain in service until 2026. Since this sub entered service in mid-1945 as the USS Cutlass and in 1973 was given to Taiwan where it has served ever since as the Hai Shih it will, with the latest refurb, become the submarine with the longest active career; 81 years if it lasts until 2026.
The USS Cutlass was the last model (the Tench class) of American submarine built during World War II. Most of those ordered were cancelled and only 29 of were built The Cutlass went on its first wartime patrol the day after Japan surrendered. Since the Tench class were the result of everything the United States had learned about submarine use and construction during the war. Moreover the Tench class boats and dozens of others built in the last year of the war underwent an upgrade by 1951. That “Guppy” program improved them still further. These subs had such a good reputation that they were in demand by allied navies and 14 were transferred, most after spending at least twenty years in American service. The Tench class boats were so popular because they were durable and proved excellent training vessels even after becoming obsolete for combat. Nevertheless Taiwan further upgraded its two Guppy subs so that they could fire modern torpedoes.
When Taiwan got the USS Cutlass it was a 1,900 ton (surfaced), 93.4 meter (307 feet) boat that carried a crew of 84. Years of service reduced it to the status of a training boat that rarely went to sea. The latest refurb will change that and strengthen the hull and upgrade the navigation equipment. Apparently some of the original ten torpedo tubes are still operational. In its prime this boat could do 33 kilometers an hour on the surface and 29 submerged. It was built to operate for 48 hours underwater at a speed of seven kilometers an hour. The second U.S. World War II era sub Taiwan has is slightly older and will apparently continue serving as a training boat. Soon, if not already, the older Guppy will be unable to submerge during training, even to periscope depth and will have to be retired unless the Hai Shih refurb works out so well that it justifies doing a similar treatment for the other old sub.
The only modern subs Taiwan has are two Hailung class boats built in Holland and entering service in 1986. These 2,500 ton boats are armed with twenty torpedoes and Harpoon missiles (launched from the torpedo tubes.) But there's a new problem as well because of plummeting morale among the 200 sailors who run these boats. Years of delays in obtaining new subs, and dim prospects of ever getting them, discourages qualified young sailors from volunteering for the submarine service and many old hands are retiring as soon as they are eligible.
Meanwhile Taiwan’s IDS (Indigenous Defense Submarine) program moves forward in response to the fact that Taiwan is running out of time to find replacements for its aging submarine force. Taiwan now admits that the search for a foreign shipyard willing to build them eight diesel-electric submarines failed. None of the European shipyards that specialize in this sort of thing would do it, as they feared economic retaliation from China. The United States had not built a diesel electric sub since the 1950s. Getting an American shipyard up to speed on building diesel electric subs turned out to be too expensive. The 2011 search effort did compile a lot of useful information on costs and the more reliable (resistant to Chinese threats) suppliers. It turned out that a lot of American manufacturers could produce components for diesel electric subs even though most of their regular work is for nuclear boats. But aside from the nuclear propulsion, a sub is a sub and the American were willing to supply Taiwan with components.
Alternative solutions were investigated. Publicly, Taiwan says it wants the subs for anti-submarine work. But it's been pointed out that there are cheaper and more effective anti-sub capabilities available via helicopters, aircraft and, UAVs. What is left unsaid is that the subs could also be used to shut down China's ports, crippling the economy and causing lots of political problems for China's leaders. It's also possible to shut the ports without using subs as air dropped naval mines or just threatening to attack any merchant ship entering Chinese waters.) But nothing does this sort of thing as effectively as a submarine, especially a very quiet diesel-electric sub.
Ideally, Taiwan wants eight new diesel-electric boats, preferably with AIP (air independent propulsion). This would drive the price up to nearly a billion dollars a boat. Building them in Taiwan can also be helped by other nations threatened by Chinese naval power. India, Japan and South Korea all build subs and have local suppliers willing to provide Taiwan with components and technical assistance. So it appears that Taiwan can get away with building the subs locally. While European firms won't sell Taiwan submarines they are apparently less reluctant to quietly sell components, tech advice and training. The IDS effort could still fail, especially when the detailed cost estimates are presented to parliament. But if Taiwan wants to save its submarine capability it’s now or never and IDS is the last best hope.