The South China Sea is supposedly very challenging to navigate for submarines in some areas, especially large types. Is its unique underwater ‘littoral’ topography a major issue?

The topography of the South China Sea is very difficult to navigate because of its high tectonic activity. The bottom is in a constant state of change. Some areas of the South China Sea are very deep, with sudden changes in depth to very shallow, near vertical-like structures that can rise to the surface.

These pinnacles are navigation hazards and, if not detected in time, may result in a submerged collision. Measuring bottom depth below the submarine may not give it enough time to maneuver out of the way of a near-vertical topographical change just ahead.