This document introduces bENCs, a new S-57 product containing high density bathymetry data for use in electronic chart systems. BENCs are produced from hydrographic survey data and contain contour lines and spot soundings without other navigational information. They are meant to be used alongside ENCs to provide more detailed depth information for confined water navigation. Potential producers include port and waterway authorities, while potential users are pilots, vessel traffic systems, and software for confined waters. Examples of existing bENC projects include coverage of the River Elbe in Germany and bENCs of the Port of Hamburg produced as part of the EFFORTS project. BENCs offer a simple production process and provide additional value to ECS