In the daytime, what shape indicates the presence of a long tow?

The shape that indicates the presence of a long tow during daytime is a diamond. According to navigation rules and the International Regulations for Preventing Collisions at Sea (COLREGs), vessels that are towing or pushing another craft are required to display specific day shapes to signal their maneuvers and the nature of their vessels. A diamond shape is used to signify that a vessel is engaged in towing operations and indicates that the tow is longer than 200 meters, which requires special attention from approaching vessels. This signaling is crucial for mariner safety and helps to prevent accidents by alerting other vessels to the presence of an extended tow. Understanding these shapes enhances situational awareness and navigational safety on the water.