Few details missing is the fact that if SCP-2770-1 fails to get the attention of a target vessel or a ship approach him without the intent of rescue, it will be pulled underwater and not resurface for at least 124 hours.
Also the fact that after a ship is "swallowed", SCP-2770-1 won't resurface for at least 242 hrs (more, depending on how large the ship is), implying that there's some form of digestion. SCP-2770-1 didn't resurface for a single digit (It was censored) year after swallowing the facility.