Relief Shading, like Google street view but for under water terrain is now available in the i-Boating app.

 i-Boating relief shading is like Google Street View, but for underwater terrain (Sea View). It's a visual representation of what the underwater terrain looks like. If you were to drain the oceans/lakes of all the water, that is the kind of view relief shading attempts to show.

Here is what the terrain looks like off the coast of Marblehead, MA.

This is what the bottom of Lake Powell looks like.

This is what the bottom of Lake Tahoe looks like.

This is what the bottom of Smith Mountain Lake looks like.