There is definitely nothing wrong with the idea of speeding the chart up to "elongate" the fish echoes... (it does make them longer and easier to see)...
A good way for users to understand this concept is visualizing that there are very few successful "pings" that actually hit the fish in the thin SI beam...and speeding the chart up allows the unit processor to take those very few successful "ping" echos and stretch those ping echos out across the screen...
It's just a matter of interpreting what you are seeing for you to best use your unit...
I speed up my chart when I am scanning bridge pilings because of the same scenario...there are very few successful "pings" that reflect off the bridge piling..making the piling show on the SI image as a thin strip....
Speeding the chart up allows the unit processor to take those very few successful "ping" echos and stretch those echos out across the screen...making the bridge piling "look" wider on the SI image...
Good shots filletfetish...
Rickie