In Dec 2004, I went on a liveaboard cruise to the Similans, off the coast of western Thailand. You may immediately be thinking about the tidal wave, and in fact, I left Phuket 36 hrs before the event. Didn't bring a camera, so no pictures...
I booked a last minute berth on the Rhapsody though Siam Dive 'n Sail, who were very helpful and quickly responded to emails. I was also somewhat interested in the Le Mahe, since it was quite a bit cheaper, and was told there was a space available. Then I was told that I would have to share with a female, and they'd have to write to her to get her ok. Then they told me that actually, sharing would involve sharing the bed! They didn't think that she'd be agreeable to that... So I ended up on the Rhapsody, which was actually my first choice because it had fewer passengers (8 vs the 12 of Le Mahe), and as it turned out, I still shared a cabin with a woman, but it was a bunk-bed cabin.
I arrived in Phuket in the early afternoon and took the minibus to town. The minibus stops at a place where they try to sell you tours and hotel rooms. This is the price you pay for paying less than a taxi to get to town. Since I wasn't in a hurry, it was ok. The Rhapsody was leaving in the early evening from the pier at South Patong beach, and I got dropped off there. I had thought I might be able to drop off my bags at one of the hotels there, but the one I stopped at wasn't keen on that idea. Fortunately, a little while later, I noticed the Oceanic pickup (Oceanic operates the Rhapsody) which had supplies for loading onto the boat. So I managed to get my stuff on board and be free to wander around town.
I spent some time walking up and down the beach road, and stopped by the supermarket. This supermarket, Ocean Center, is in the basement of a building on the beach road. The tsunami water trapped and drowned a number of people who where shopping there at the time. Not pleasant to imagine.
Anyway, after walking around a while, had a bit of dinner and met up at the pier to join the boat. We all got in a longboat and got driven to the Rhapsody, where they gave us the pre-trip briefing. There were 8 of us -- a couple each from Germany, Holland and Sweden, and a single woman from Sweden, and me. The divemasters were yet another Swedish woman, Marie, and an englishman, Clive. There were 4 Thai crew.
The next three and a half days were spent diving. The day was: get up, have a very light breakfast snack, dive, have real breakfast, relax, dive, have lunch, relax, dive, relax, do night dive (I didn't do any of those -- 3 dives a day was enough for me), eat dinner, relax, sleep. Repeat.
This was my first liveaboard and it was a great experience. It was a reasonable time period (3 nights 4 days), so not too long. I initially was worried that all that diving would get repetitive feeling, but it didn't. And because there was plenty of SI between dives to rinse off, eat, and nap, it was very relaxing. Plus, having only 8 guests meant that there were only two groups to get into the water, so that wasn't a hassle either. Clive had been DM on some of the cattle boat liveaboards. South Siam Divers uses boats that travel in pairs. Each boat takes 35 guests, so there are 70 people to get into the water at each stop!
We were fortunate not to have to share the underwater except for at Richelieu Rock. Our schedule and itinerary varied to avoid the other boats who are apparantly on tighter schedules. On our last dive, we went to Shark Rock (so-called because there are two sets of rocks that stick out of the water that look like the dorsal and tail fins of a shark -- the only actual sharks we saw were some leopard sharks at various sites), and were the only boat there -- all the others were at Elephant Rock. That day, there was a reasonable current, and Clive told us that at Elephant Rock, there's only one area that's protected from the current, so all those boats' divers would be there. A jacuzzi dive.
All in all, a very nice trip. Calm seas, beautiful weather, superb dive guides and good fellow passengers/divers. Only disappointment was no pelagic fish sightings