TAIPEI (Taiwan News) – Shipbuilder CSBC Corporation, Taiwan is working overtime to adjust items on the indigenous submarine the Narwhal, but it is not certain whether sea acceptance tests will be able to start this month as scheduled, Defense Minister Wellington Koo (顧立雄) said Wednesday.

Following harbor acceptance tests, the minister faced questions about the next phase of the project. As no sightings had been reported of the Narwhal heading out to open waters, there were questions arose as to whether the original timing for the tests could be maintained, per Radio Taiwan International.

Koo said staff at CSBC’s Kaohsiung yard were working overtime to fix problems discovered during the harbor acceptance tests. Whether the sea acceptance tests can start in April as planned is impossible to determine, according to Koo.

The next phase will only be allowed to begin if all issues are resolved, the minister said. In any event, the handover of Taiwan’s first indigenous submarine to the Navy is still scheduled for November.