It is recommended that a dive team diving from an anchored boat have a trail line _____ long with a buoy at the end.

The recommendation for a dive team to have a trail line that is 100 feet long, with a buoy at the end, is based on safety and operational efficiency while diving from an anchored boat. A trail line of this length provides an adequate buffer between the boat and the divers, allowing for easier management of the diver's surface marker buoy. It helps in maintaining a connection to the surface while minimizing the risk of entanglement with the boat or surrounding equipment.

Having a buoy at the end of the trail line serves multiple purposes: it allows the dive team to signal their location to the boat and other divers, and it helps to keep the line visible on the surface, ensuring that it remains accessible for divers when they ascend. This can be particularly important in areas with currents or heavy boat traffic, as it enhances safety and organization.

Other lengths like 50 ft, 75 ft, or 150 ft may not provide the same level of effectiveness in safety and communication. A shorter line could restrict the divers' movement and experience as well as create a higher risk of miscommunication or accidents with the boat. Conversely, a longer line could lead to unwieldy handling and potential tangling issues. Hence, 100 feet strikes an optimal balance.