The message line is simply a length of light line, which can be _________________, propelled, or floated further than the tow line.

The message line is designed to be an effective and flexible tool in towing situations. It is a lightweight line that can be easily thrown, allowing it to be heaved over distances greater than the tow line itself. This feature is particularly beneficial in rescue operations or when communicating essential messages between vessels, as it can be quickly deployed without the need for heavy equipment.

The ability to heave the message line means that crew members can use their strength and technique to throw it further, ensuring it reaches the target vessel or location when needed. This makes it an invaluable resource on the water, facilitating better communication and coordination during operations. The method of heaving allows for quick action and response, which is critical in emergency situations where time is of the essence.