Tug Ahead, Barges Behind

• In addition to the red light on the port side of the tug and the green light on the starboard side, looking at the front of the tug you'll see two white lights, one atop the other, on the mast. If the tug and barges are more than 200 meters --- almost 220 yards --- in total length, you'll see three white lights, also one atop the other. On the rear of the boat, you'll see the usual white stern light but above it a yellow towing light must be visible. Once the tug drops the tow, it reverts to red and green side lights, a single mast light and a single stern light.
  
  

"Push Boats"

• Push boats, those specialty tugs that push barges ahead of them, and any other tug that's pushing the barges instead of towing them or carrying a barge at their side, need not display mast lights. Instead, the have to display the red and green lights on their port and starboard sides, respectively. The also must display a white stern light, like the tug that's pulling barges, and two yellow towing lights, both in a vertical line above the stern light, indicating that the vessel is towing. Once the tug or push boat is free of the barges, they display side lights, the white stern light and a white mast light.
  
  

Composite Units

• Composite units, called an integrated-tug barge, don't carry towing lights; rather, since the tug is locked into a special notch in the barge, the unit is lighted with a white bow light on the forward mast, a mast light on the main mast, mounted higher than the bow light, red and green side lights and a single white stern light. When the tug releases the barge, its lights do not change.
  
  

On the Western Rivers

• All rivers north of the Huey P. Long Bridge in New Orleans --- the Mississippi, the Ohio and the Missouri --- are called the "Western Rivers" in the Navigation Rules. These rivers served the inland navigation needs of the Republic when it was new. The lighting rules on the Western Rivers require a tug, regardless of the method of tow, to have a red sidelight to port, a green sidelight to starboard, no white stern light and two yellow tow lights in a vertical line at the rear of the tug.