Yes sonar can be used at periscope depth. Surface ships also have sonar arrays on them. They are usually used to detect submarines.
You use Sonar
They use Radar , Sonar, and at periscope depth- optical range finders, the tech manual for the latter is over 300 pages, so its a skilled craft to operate these specialized sights.
SONAR
Scientsts use sonar to map the depth of water in sea and river etc..,they also use sonar to locate and identify object underwater
Scientist use the device "Sonar."
It depends on the submarine. If measure the distance from the top a fully extended periscope to the bottom of the boat you will get the "Depth of the Keel" at which the periscope is out of the water. Generally between 30 feet and 70 feet.
Periscopes allow a submarine, when submerged at a shallow depth, to search visually for nearby targets and threats on the surface of the water and in the air. When not in use, a submarine's periscope retracts into the hull.
Scientists use echo sounders or sonar technology to measure ocean depth. These tools work by sending sound waves down into the water and measuring how long it takes for the sound to bounce back, allowing scientists to calculate the depth of the ocean floor.
The depth of the ocean is found using sonar. Having two eyes allows an animal to have depth perception. Surrounded by eminent professors, the biology teacher felt out of his depth.
With sonar
Sonar determines ocean depth by measuring the time it takes for sound waves to travel from the surface to the ocean floor and back. It also relies on the speed of sound in water, which is approximately 1,500 meters per second. By calculating the time delay and knowing the speed of sound, sonar can accurately calculate the depth of the water.
sound waves can penetrate the ocean floor.