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• $69 for Two Hour Boat Rental, Valid Monday-Thursday, Up to 8 People ($170 value)
• $94 for Three Hour Boat Rental, Valid Monday-Thursday, Up to 8 People ($255 value)
• $89 for Two Hour Boat Rental, Valid Friday-Sunday, Up to 8 People ($170 value)
• $119 for Three Hour Boat Rental, Valid Friday-Sunday, Up to 8 People ($255 value)

Radar: Eyes in the Back of Your Hull

Ship captains have sharp eyes (despite their eye patches), but even they sometimes rely on technology to see for them. Navigate the science of radar aboard the _S.S. Groupon._

A dense fog covers the stormy ocean, the clouds a jet-black veil obscuring the moon as if were a widow in mourning. A vast chasm of dark sea and choppy waves lies between sailor and shore, boat and bedrock, yacht and yacht club. The captain sees nothing ahead, and the biting wind makes it impossible to hear (and thus avoid) other boats navigating the perils. Yet this picture is not so hopeless thanks to a vital tool in the maritime arsenal: the iconic blips of a radar screen revealing nearby obstacles even in the dark. The technology allows for safe travel when visibility is low or even nonexistent. But how does it work?

In the 1880s, physicist Heinrich Hertz discovered that radio waves could be used to detect solid objects, a scientific breakthrough that led to the concept that makes radar possible. Much like a dolphin uses sonar for echolocation, a radar antenna blasts out radio waves, which, as part of the electromagnetic spectrum, move at nearly 300 million meters per second, or the speed of NFL running backs. As these waves pulsate, the antenna itself rotates atop the boat, creating a 360-degree field of transmission. When a wave touches an object, it bounces back to a dish attached to the boat, which scoops it up like a baseball glove fielding a ball. Since the waves that never interact with an object continue traveling indefinitely, they create “negative” space within the field of vision, essentially revealing safe waters ahead. Together, the information paints an instant picture of the boat’s surroundings, acting as the captain’s ears, eyes, and whiskers in times of trouble.