The project of this boat is an auxiliary mid-size passenger boat, built in Poland for the needs of the Soviet Navy. In addition to the passenger version, there were also medical boats based on this project. In total, in the period from 1978 to 1985, 40 boats of this type were built.

The passenger boat of this project is designed to carry up to 22 passengers, and the medical boat - up to 15 patients. The boat has a cargo hold, the autonomy is up to 6 days. The seaworthiness ensures the sailing of the boat in a sea state of up to 5 points.

Medical boat SN-391 laid down on 18 March 1979 at Wisla Shipyard, Gdansk, Poland (yard No.7), commissioned on 29 September 1979 and was assigned to the Black Sea Fleet.

Then renamed to MK-391, and from 31 July 1992 - passenger boat PSK-391.

In 1994 the PSK-391 passenger boat was excluded from the Black Sea Fleet and sold to a private owner, changing several owners and names (Altair, then Liza, then Nautilus-1, then Nautilus-One).