TAIPEI (Taiwan News) – The Narwhal indigenous submarine is likely to venture off to sea Thursday for a new round of tests, though it is unlikely to make the deadline for its commissioning by the Navy.

The sea acceptance tests were initially supposed to end in September, with the commissioning set for November. However, the Narwhal hasn’t been seen for 147 days, the Liberty Times reported Wednesday.

The submarine’s next appearance is now expected Thursday morning, with observers looking for the start of diving tests at limited depths. In a later phase, the Narwhal will still have to perform diving to deeper waters.

Shipbuilder CSBC Corporation Taiwan did not provide any information on the schedule, but military fans were said to be preparing banners to wave near Kaohsiung harbor Thursday. The submarine made three surface trips to sea in June and July.

Government and military officials acknowledged it would be difficult for the project to meet official deadlines. The Navy may seek compensation from CSBC if the company cannot deliver the Narwhal this month.