Sounders

Still being a bit new to all this;)
If i attach a Fish finder to my Raymarine C80 does it show whats just below my boat or will it show infront and behind aswell?
I have seen Rib Voyages over here going in and out of the caves in Sark and wondered if they have some equipment that would display whats infront of them?
Many thanks
Tony

It only shows what is under you at the time - depending on the depth as it is a cone shape.

You can get forward looking sonar but it is very expensive and you need to be going very slowly as it doesn't look that far ahead.

http://www.echopilot.com/products/forward_looking_sonar/fls_platinum_video.aspx