sounding pole

Throughout this period, lead and line sounding operated alongside sounding poles, particularly when navigating in shallower waters and on rivers.

This method revolutionized hydrographic surveying, as it allowed a quicker, less laborious, and far more complete survey of an area than did the use of lead lines and sounding poles.

This greatly increased the speed of acquiring sounding data over that possible with lead lines and sounding poles by allowing information on depths beneath a vessel to be gathered in a series of lines spaced at a specified distance.

In either case if there was any uncertainty about the depth of water a man would be positioned on either side of the foredeck (or at the front end of a barge, if a barge was being pushed) to sound the depth using sounding poles, marked with alternating black and white stripes.