Here we are dealing with a vessel RESTRICTED IN ABILITY TO MANEUVER as seen below.

As you will note the main difference are the THREE vertical lights with TWO RED and ONE WHITE in the middle. Also there is a different day shape.

Below is a vessel involved in a TOWING operation.

As you will it has the same RED ONE RED vertical lights BELOW the WHITE masthead light. In addition it has the YELLOW light.

Hugh Simpson