The bomb planted on an oil tanker after its oil was stolen in Malaysian waters on Sunday was fake, the navy said yesterday.
Explosive Ordnance Disposal officers from the 2nd Naval Area Command destroyed the "bomb", which was on the flying bridge near the Lapin's control room, using a high-pressure water gun. The device comprised an electrical circuit and battery without any explosive powder. Pirates used it to threaten the crew.
"The trick was aimed at increasing anxiety among the crew and prolonging the time before authorities were informed, paving the way for the pirates' smooth getaway," said 3rd Naval Area Command chief Vice Adm Sayan Prasongsamret.
None of the 15 crew were injured in the attack, and the vessel anchored safely near Ban Pak Bara in Satun late on Sunday.
While Thai officers work with Malaysian, Singaporean and Indonesian authorities to patrol the Strait of Malacca, the attack will spur authorities to boost their policing efforts, Vice Adm Sayan said.
The Lapin was transporting 2,000 tonnes of bunker oil from Singapore to a Krabi-based power plant when it was attacked by armed pirates.
It is the first report of piracy in the Andaman Sea this year. In 2014 there were five to six such attacks in the South China Sea.