It always amazes me that wooden things can last that long. SE Asia isn't an area where I'd look for old wooden things. But burial makes sense. People with an intimate connection to the sea would certainly look to it as having some mystical aspects and death at sea would be common to them. Makes sense to bury important with some connection to water.
Yup...And, you probably wouldn't look in Florida for mummies either. 169 7-8,000 year old mummies...90 have complete brains...And, guess what, they're Europeans.