They are 2 tank dives, but they have a compressor on board, as long as you are diving air all you will need is 1 tank, but I always dive a mix so that doesn't work for me & I usually dive doubles.
The in-shore wrecks such as the Tug, Tiger or Reef (which consist of some subway cars & an old barge) are about an hour boat ride. These are all less than 70fsw. Vis is typically 10-15 ft.
The real interesting stuff such as the Morgan, Luchenbach, Clark & Webster are close to 2 1/2 hour ride. These are in the 100fsw range & vis is typically 20+ ft.
We have some deeper stuff, but the trips are pretty spread out on the schedule & range from 140fsw to 200fsw + & we get better than 50 ft of vis.
We just went on 1 to the Chenago last weekend & there is video on this forum in a trip report. I'm the diver shown going down the line & am in it quite a bit, wearing doubles with Shark stickers & carrying 2 bottles, 1 yellow & 1 silver.
There is usually plenty of room except for this past weekend when they were running 1/2 priced dives & divers came out of the woodwork to fill the boat. We were set to dive the Morgan on Saturday in the AM, but Mother Nature chimed in & kept us close to shore at the Tiger. I am going to do a report soon.