The sub was capable of descending to 5,000 feet (1,500 m) below the surface and could carry 24 passengers at a time, in addition to its crew.

[5] After the sinking of the submarine USS Thresher (SSN 593) in April 1963, the United States Navy discovered multiple limitations in deep sea rescue capabilities using the McCann’s rescue bells, developed by Allan McCann in 1929.

This updated system is easier and faster to deploy than the DSRVs, controlled remotely, and crew is transferred to a decompression to avoid sudden pressure changes.

A special system was developed to control the ballast and the thrusters to make precise movements.

[6] The Mystic is equipped with electric propulsion, batteries, sonar, navigation systems, and communicating, operated by two pilots.

The Mystic is also equipped with an arm to clear debris on hatches, which contains a combined gripper and cable cutter.