A boat chartering company $(BCC)$ has a name and an address, as well as a unique commercial

register code $($CRC$)$ for identification. The BCC is organized in boat charter offices $($BCO$),$ which

are located on islands in different countries. The BCOs have an address in a country and a unique

$BC{O}_{?}$number $($BCO$\_$no$).$ The BCO offers different BOATs, which are all characterized by crew and

passengers. All boats are identified by a unique BOAT$\_$number. There are three different types of

boats: sailboat, yacht, and speedboat. The boat type speedboat is additionally characterized by

Max$\_$Speed and Range. Each depot has BCO has employees. There are two types of employees:

Office$\_$Employee and Crew$\_$Members. An employee is identified by a SSN and contact data.

Contact data consist of an address, an email and a phone$-$number.