Which item is NOT required for boats according to the safety regulations?

The safety regulations for boats outline essential equipment that is necessary for safe operation. A radio, while valuable for communication, is not mandated for all types of boats. The requirement for a radio often depends on the size and type of the vessel, as well as the area of operation. For smaller boats, particularly those that operate in inland waters, having a radio may not be necessary according to the regulations.

In contrast, items such as a bailer, line, and oar are generally required because they help ensure the vessel's safety and the ability to respond to emergencies. A bailer is essential for removing water, a line can be used for securing the boat or towing, and an oar provides means of propulsion or maneuvering when the engine fails or if the vessel needs to be moved in a controlled manner. Thus, while a radio is important for communication, it is not universally required, making it the correct answer in this context.