The date was April 3, 1983.
Those on board the 15m-long catamaran sailing out of Changi Sailing Club expected their pleasure cruise to be anything but notable. But by the end of the week, the world would come to know of the Siddhartha and its six passengers and crew.
One of them was Singaporean Jenny Toh Swee Neo, then 35, the co-owner of the yacht.
Now 65, her wrinkled hands hold up a faded brochure with the words "Yacht Siddhartha" while speaking with us. Even though it has been more than 30 years, Miss Toh remembers her days running a private charter service with then-boyfriend, German national Peter Marx like it was yesterday.
The attack on the Siddhartha made headlines then, but this is the first time she is telling her story publicly. Back then, she had left it to Mr Marx to answer the questions.
Slowly, she narrates the entire incident to The New Paper on Sunday over old newspaper cut-outs at her home last week. She hasn't forgotten a single detail. But it is a story that she has shared only with close friends so far, so it takes some persuasion for her to open up .
"It was such a long time ago," says Miss Toh with a wistful smile. On April 3, the couple took on a charter for four German ham radio operators - amateur radio enthusiasts who travel to remote locations to broadcast signals to others around the world.
They had decided on Amboyna Cay, an island in the Spratly Islands group. Claim over it is heavily disputed by Vietnam, China, Malaysia, Taiwan and Philippines.
"We thought it was uninhabited," says Miss Toh.
On April 10, as they circled the island, they discovered they were wrong.
They saw men in military uniforms waving flags at them. Two cannons were pointed in their direction.
"We didn't know if they were asking us to go towards them or go away. So we tried sailing away." Then she heard the frightening sound of artillery fire.
"The first salvo missed us. The second one didn't. The shells kept on striking the ship.
"Peter was struck by shrapnel on his shoulder. One passenger got hit and fell overboard. No one saw him again," says Miss Toh.
Another of their passengers broadcast on their ham radio: "They are shooting at us... The boat is on fire... We are leaving now."
The five remaining passengers who survived the gunfire swam out to their dinghy, which had been freed from its tethers by the explosion.
They huddled together in the dinghy, keeping their heads low to avoid detection and watched as the Siddhartha burned in the distance, broke apart and then sank.