Sonar would be an obvious means to determine depth of the water ahead regardless of the water opacity. Once the front end touches water, an underwater sonor depth finder could detect and display the water depth ahead.
Replay available now: A handful of emerging network technologies are competing to be the preferred wide-area connection for the Internet of Things. All claim lower costs and power use than cellular but none have wide deployment yet. Listen in as proponents of leading contenders make their case to be the metro or national IoT network of the future. Rick Merritt, EE Times Silicon Valley Bureau Chief, moderators this discussion. Join in and ask his guests questions.