classDiagram
    class Logbook {
        +int id
        +int boat_id
        +int shipmaster
        +int steering_person
        +bool shipmaster_only_steering
        +datetime departure
        +datetime arrival
        +string destination
        +int distance_in_km
        +string comments
        +int logtype
    }

    class LogbookType {
        +int id
        +string name
    }

    class Rower {
        +int logbook_id
        +int rower_id
    }

    class User {
      ...
    }

    class Boat {
      ...
    }

    Logbook "*" -- "1" Boat
    Logbook "*" -- "1" User : shipmaster
    Logbook "*" -- "1" LogbookType
    Rower "*" -- "1" Logbook
    Rower "*" -- "1" User