Yes the ferry on the way to the Island was full but did not feel overcrowded, everyone had a seat. On the way over we stayed on the bottom deck, the top was packed. On the way back the ferry was much less crowded and we sat on top.
It was a choppy, windy day so the ferry ride was about 50 min.
We came back on the 2:00 ferry so we had about 2 1/2 hours on the island. If it had been a warmer day we would have stayed until 4:00. We did stingray-city there.