

Initially United Towing tugs retained their own flag but used a buff funnel with black top and a narrow upright panel touching it. Stylised SOS letters run vertically: the S forms are light-blue squares crossed by an undefined white diagonal, and the O is a darker-blue circle containing a white star throughout with a blue U.
The eventual flag uses stylised company initials. The star is common to both partners, while its position within O recalls Blue Star’s ball.