The 2.5 inch Tow Line is connected
to the Port side, main winch.
used to tie the
is larger than
"Towing astern" means the tug is in front of the ship in tow called a tow, and pulls them after itself. The tow astern presents special problems, since other vessesl can cross between the two and cannot really stop them, just warn them. This means that the crossing vessel is in the wrong and will very likley strike the tow line and be damaged or sunk with all aboard.
The tug towing astern carries two white mast lights in a vertical line as well as the red and green navigational lights on its port and starboard sides. It will also have a yellow towing light above a white stern light. A tow more than 200 meters long is marked with an unlighted diamond shape on a staff at all times. The tow is illuminated at night by a spotlight from the tug. A tow less than 200 meters long must have side lights -- red to port and green to starboard -- and a white stern light.
The tow line will reel out toward the stern when the this brake band is released. That's how the tow line is held in place during a tow. The 2.5 inch steel cable has a very high pulling strength, BUT, it also the weakest link in the towing system. If the vessel were starting to sink, there is no choice but to release the break and let the remainder of the line reel out and sink with it.