A Phuket-based liveaboard sank about 11 nautical miles from Phuket as it was heading back from the Similans. Not all passengers involved in the 11pm Sunday incident have been accounted for yet.

The Phuket Gazette reports that according to the captain of the liveaboard Dive Asia I, a freak storm caused the 6 month old, 30m long boat to sink. He described a vortex, referring to it as “red wind”, that approached the boat from a northerly direction.

The vortex was first spotted on the radar when it was 3 miles away, but it hit the boat just 10 minutes later, spinning it violently and eventually causing it to sink.

At 2am local fishermen and police rescued 23 survivors from the boat’s life raft found near where the mishap occurred. 6 people are still unaccounted for and includes German, Japanese, Austrian, Swiss and Thai passengers.

The search, conducted by the Royal Thai Navy and involving a helicopter, will continue today.