The ferry was surprisingly easy to board. Though we did have to deal with some turkmenistan visa madness. The guys at immigration said we weren't on the list, and the paperwork we had from visa machine was also apparently worthless(a message in russian say we have just been approved and we don't have the LOI). We took a taxi to turkmenistan embassy in baku, and spoke to some girl over the intercom[because letting us into the gates was apparently too much trouble] to tell us that she can't help us, and that this russian message from visa machine was meaningless. So we emailed and called visa machine people but heard nothing on the timetable we required. We had nothing else to do except go back and doubled check that we weren't on the list. So 3 hours later we are back to look at the turkmenistan list again and we were on it! so we drove the Timmy(our Fiat panda) on the Dagestan ferry, took off for Turkmenbashi at about 5:30pm.
The room that we had on the Dagestan was special. Two nasty bunks and a bathroom that didn't have light, and also the toilet was broken. Full speed ahead for 13 hours and the boat engines stopped at about 8am. When we looked out the land was still pretty far away. We proceeded to sit there in the middle of Caspian Sea until about 2pm where the ferry looked like we were heading to port. We moved again for maybe an hour but then stopped again and sat there. Around 4pm the "maid" took our bedding sheets. We were thinking that she probably knew we were moving and that we would be at the port soon. We stayed up until about 2am, and finally gave in to sleep. The boat didn't move until 8am the next day, so we were sitting on the nasty bunks without sheets for 14 hours. wtf?
The entire time there wasn't any clear communication of what was going on. I had a rough idea from Brian at Baatar Hero who did it in 2010 who said they did roughly the same thing, except at 10pm they were docked and off the boat at midnight. They were luckier than us. The girl from visa machine mentioned in her email that it took her 75 hours to cross. I'm happy to say that I don't think I'll ever want to do that again.