Thanks for the memories, TT.
I lived in Phuket for ten years, and I guess I just got used to seeing the boats. A chum wanted to buy a 'longtail' (Yes, that is their proper name) about five years ago - we could get a new one built for 50,000 Baht (about 1,000 pounds at today's exchange rate.)
One can buy the propellers for these longtails in almost any hardware shop, for the princely sum of 250 - 300 Baht (five or six pounds)
The one thing you just cannot get is a silencer for the engine! Thais believe the noise keeps evil spirits away, so the louder the better.
Alas, I now live in the North East of Thailand, about one thousand kilometres from Phuket and also a long way from the nearest sea.
Geoff