What is the function of a surface marker buoy (SMB) during a night dive?

The function of a surface marker buoy (SMB) during a night dive primarily revolves around enhancing safety and communication. Specifically, it helps surface vessels identify a diver’s location. At night, visibility is greatly reduced, making it crucial for divers to have a way to signal their presence to boats and other vessels. The SMB is typically brightly colored and can be illuminated or reflective, making it visible from a distance even in low-light conditions. This not only helps prevent accidents but also allows the diver's surface support team to monitor their position and ensure their safety.

The other functions listed do not align with the primary purpose of an SMB. For instance, SMBs are not designed to enhance buoyancy or serve as weight; rather, they are used for marking a location. Additionally, they do not obscure divers from marine life; in fact, they can draw attention due to their visibility, which is not an intended function. The primary objective remains safety and location identification for both the diver and surface vessels.