Point taken Colin. But the forward looking thing doesn't tell you what's on the other side. If you see what I mean.
On more than one occassion as a Nav I had to make a decision to either let the ship "slide" over a sand bar or find a way around it.
Only 2 areas in the world did I find it "expedient" to charge at the sand bar (fingers, toes, legs and so on crossed) and just hope I'd made the right choice. The main area of concern was always the SE corner of the UK. Those sand banks moved with every change of tide, so they had to be "soft" and not puddled in. If the operational requirements hadn't sort of demanded that "some risks" had to be taken then I could well have not recommended it to the command. As one (well respected) Captain observed, it was my Masters Certificate at risk as well as his. But get the mathematics right, hold the nerve and trust in the lord.
I very much doubt if commercial ships have something as exotic as a forward looking sonar/depth finder. Just the opposite I think. Observe the standard commercial ship approaching a port. See how far away from the port entrance the ship stops and waits for a pilot. Close quarter meetings and shallowish water give many "deep sea" Masters palpitations.
But, having said that, and I know you are sort of familiar with nautical charts, many forum members are not. Hence my query.
To somebody living in (say) Nottingham a nautical chart would just be gibberish. So many symbols, odd lines and so on.
I also know (to my cost) that this is a "Model Boat" forum, but that in itself indicates that the members are at least a little bit interested in ships. Marine charts are a vital part of that. Sorry to go on for so long, but so many misconceptions get aired here. BY.