TAIPEI (Taiwan News) — Taiwan needs more than 10 submarines to have an effective undersea force, CSBC Corp. Chair Chen Jeng-horng (陳政宏) has said.

The US military previously assessed Taiwan’s needs and concluded that it would require at least 12 submarines, Chen said in a SET TV interview released Saturday. Given Taiwan’s location between the Strait of Malacca and Northeast Asia, it is vital to protect maritime transportation routes and foreign trade lifelines, he said.

Taiwan also needs to counter a potential Chinese amphibious landing or blockade, Chen said, adding that strategic ambush areas exist in Taiwan’s northeastern, eastern, southwestern, and southern waters. Taiwan would need to deploy one submarine to at least three of the areas, he said.

Chen said submarine fleet planning is generally calculated using a three-to-one ratio. For every submarine required for combat operations, another is typically assigned to training, while a third undergoes maintenance.

The chair said the design of the first batch of follow-on submarines will not differ significantly from the Narwhal prototype. However, the equipment used on the prototype and the first two follow-on vessels will not be completely identical.

In some cases, he explained, Taiwan may find products offering better overall performance. Since equipment from different manufacturers can vary in weight, size, or connector specifications, replacing one component often requires redesigning associated systems and nearby sections.

If major design adjustments are needed, they will likely be implemented in later production batches, he said.

The Narwhal successfully fired exercise torpedoes during sea trials on Thursday. It conducted its seventh underwater test on Tuesday.