Question

PLEASE HELP!!!!!!!

What technological development during the 1930s allowed for the collection of more and better undersea data and, therefore, the creation of nautical charts?

Answer 1

Sonar - Wikipedia, the free encyclopedia
en.wikipedia.org/wiki/Sonar
Wikipedia
Two types of technology share the name "sonar": passive sonar is essentially .... During the 1930s American engineers developed their own underwater sound ... This pulse of sound is generally created electronically using a sonar .... Sound travels more slowly in fresh water than in sea water, though the difference is small.

Answer 2

Thank you so much!!!!!