Taiwan Uses Naval Mines Designed Over A Century Ago

The mine seen in the photos taken during the exercise is likely a Mk 6 Mod 15, which a newsletter published by the U.S. Navy’s Association of Minemen explains is an inert training variant of the Mk 6 Mod 14. Training to load the Mk 6 Mod 15s points to the Taiwan Navy’s intent to potentially deploy the active Mod 14 mines should a conflict arise in the future. To further support that assertion, a text published by Drew Thompson for the Institute for National Strategic Studies claims that Taiwan’s stockpile of Mk 6 mines acquired from the United States undergoes periodic refurbishment. However, the crux of the decades-old design seems to be mostly unchanged. 

This is an interesting development as Taiwan’s newest minelayers are designed to employ a variety of more modern mine types. The plan to develop the corvettes was first announced in May 2019, when Taiwan’s President Tsai Ing-Wen first revealed the intent to construct three stealthy missile corvettes with racks for naval mines as well as four dedicated minelayers to better address the need for modernized naval mining capabilities. In January of this year, two of those minelayers were officially commissioned.

The commissioning ceremony marked a historic moment for the Taiwan Navy for two prominent reasons: Firstly, it acts as the service's introduction to automatic mine sowing. During the commissioning, President Tsai mentioned that the country’s previous minelayers were made from converted landing craft, were not designed for rough sea conditions, and required that sailors manually do the minelaying. To overcome those drawbacks, the newest minelayers manufactured by Lungteh Shipbuilding are equipped with an automatic minelaying system designed by the National Chung-shan Institute of Science and Technology. 

Secondly, the commissioning not only revealed the newest additions to the Taiwan Navy’s fleet of ships but also introduced the 192nd Fleet’s first and second minelaying squadrons, which are the first dedicated minelaying teams in the Navy’s history. Each squadron will get a single minelayer and the mines they carry are likely to be among Taiwan’s primary lines of defense if China decides to launch an amphibious invasion. 

While the newly commissioned minelayers are only now entering service, the Mk 6 mines have been around much, much longer. The first versions of the Mk 6 mine were introduced more than a century ago in response to a 1917 Bureau of Ordnance report which stated that the status of mining in the U.S. Navy was “very unsatisfactory.”

According to NavWeaps.com, a website dedicated to naval weapons history, "The 'K-pistol' of the Mark 6 used a copper antenna which extended upwards to just below the surface. This was connected by a relay to a copper plate on the outside of the mine. Seawater acted as the electrolyte of a battery which would be formed when a ship with a steel hull approached and touched the antenna. The current running down the antenna operated the relay and exploded the mine. This method allowed each mine to cover a wider area, meaning that fewer mines could be used to cover a given area than with the horn type. In modern terms, the 'K' device exploited the Underwater Electric Potential effect."

After the Secretary of the Navy authorized the construction of 100,000 mines of this type in 1917, production soon ramped up to about 1,000 Mk 6 mines a day, eventually prompting the Navy to build its own TNT factory in St. Julien's Creek, Virginia. The Mk 6 clocks in at about 1,400 pounds, with a 300-pound charge of TNT. It went on to serve the U.S. Navy from 1917 to 1985, making the Mk 6 the United States’ longest-lived mine.

There have been at least 15 variants of the Mk 6 since its introduction, with the inert Mk 6 Mod 15 being the training mine now likely pictured aboard a minelayer during the Taiwan Navy’s mine-loading exercise. According to a 1959 manual detailing the operational characteristics of U.S. naval mines, the Mk 6 Mod 14, or the active variant of the Mod 15, is a surface-planted moored mine that is fired by deflection of horns mounted on the case. It weighs the same as the other Mk 6 mines and is designed to be ideal for use against any ship or submarine. 

It is difficult to overstate just how important naval mining is likely to become amongst the Taiwan Navy’s defense strategies against China’s forces if a conflict with the mainland were to occur. The significance of such tactics is only further illustrated by the commissioning of Taiwan’s new dedicated minelayers, which are part of the country’s larger effort to bolster its naval warfare capabilities with a focus on domestically developed technologies and weapons systems. 

In the past, Taiwan has largely relied on more dated systems, as exemplified by the fact that the Mk 6s remain in service. While this could highlight potential limitations in what these new minelayers can actually seed in the waters around the island, it doesn’t mean that having a plentiful arsenal of mines both old and new couldn’t still be beneficial to Taiwan’s defense. Even a relatively dated mine like the Mk 6 is no doubt very dangerous and proven. One could easily argue that in a potential conflict with China, Taiwan will need every mine it has. Widespread mining could, at the very least, slow down China's amphibious operations by denying them easy access to key beaches and ports, while also providing precious time for Taiwan respond and for allied help to arrive.

As President Tsai alluded to in her speech during the January commissioning ceremony, the minelayers and their mines may be small but they are indeed mighty. The ships are fast, the mines are powerful, and like the country of Taiwan itself, will not be deterred by bigger more oppressive threats. 

Contact the author: Emma@thewarzone.com