I had one of my most scariest experiences on one of these boats from Koh Pha-Ngan to Koh Samui in 2000.

Those guys sail close to the wind!
Very simple: Sell loads of speedboat tickets to partyanimals, make them drunk (well nothing wrong about that) and ship them to the kick-ass FullMoon-Party at the beach of Koh Pha-Ngan. Then reduce the Nr. of boats for the way back dramatically and let the people find their way home back by themselves.

Lost rare pix from this lovely moments (2gether with the camera... and my shoes)

The result:
"News agencies on Tuesday reported that seven people were killed in the boating accident, including four Western tourists, after the vessel they were traveling in capsized between the holiday islands of Koh Samui and Pha-Ngan in the Gulf of Thailand.

Almost 20 people remain missing in the accident, which authorities believe was caused by an overloading of the speed boat..."
http://edition.cnn.com/2005/WORLD/asiapcf/01/24/thailand.boat.accident/index.html