Which technology helps avoid groundings while navigating?

The technology that primarily helps avoid groundings while navigating is the echo sounder. An echo sounder, also known as a depth sounder, uses sonar technology to measure the depth of water beneath a vessel by sending sound pulses down to the seabed and measuring the time it takes for the echo to return. This information is crucial for determining the safe vertical clearance between the vessel's keel and the seabed, allowing mariners to navigate safely through areas with shallow water.

While radar assists in detecting other vessels and land features that might pose a collision risk, and GPS provides precise positioning, neither of these directly addresses the vertical spatial relationship with the water depth. Sonar, while it can also refer to systems used for underwater imaging and exploration, is broader in scope and does not specifically include the depth measurement function as clearly attributed to echo sounders used for navigation. Therefore, echo sounders are integral to avoiding groundings as they provide direct and real-time depth information necessary for safe navigation in shallow waters.