The Condor Liberation sailed from Poole into Guernsey, arriving at 15:30 on Sunday 11 September.
A statement from Guernsey Police said officers “are investigating an incident involving a disruptive passenger on the Condor Liberation sailing between Poole and Guernsey” and that they would “like to speak with anyone that witnessed this to assist them with enquires”.
A number of people are believed to have seen the incident and may be able to help police with their enquiries.
PC Du Port can be called on 222 222, or messages can be left anonymously with Crimestoppers on 0800 555 111.
Pictured: The Condor Liberation.