October 5, 2011: A U.S. Air Force B-1B has successfully used laser guided JDAM bombs against moving naval targets. These tests involved the B-1B using its Sniper targeting pod to put the laser beam on the target. The JDAMs homed on the laser light reflecting off the moving target ships. This is the latest of many air force heavy bombers that have served as maritime patrol and anti-ship aircraft. Back during World War II, thousands of B-17 and B-24 bombers (and many two engine bombers) served to patrol and control vast ocean areas. In the last few decades, the B-52 has been active in this area. For example, for the last few years, the U.S. Department of Homeland Security (DHS) has been using B-52s to check out suspicious merchant ships approaching North America, often when the ships are still about 2,000 kilometers from the coast. The B-52s use their targeting pods to take pictures of the ship, and transmit those back to DHS. A B-52 can do this while taking part in a training exercise. B-52s have a lot of jobs to do over the oceans.
This is largely because maritime reconnaissance has been revolutionized with the introduction, and combining, of lightweight search radars and targeting pods. With the targeting pod, you can stay high (6,500 meters/20,000 feet) and far away (over twenty kilometers) and still get a close look. Thus a B-52 with a targeting pod is an excellent naval reconnaissance aircraft, as is the more recent B-1B.
B-52s and B-1Bs also practice dropping naval mines. This is something the air force has been doing since World War II, and with great success. The current air force naval mine is the Mk-62 "Quickstrike." This is basically a 227 kg (500 pound) bomb, with a sensor package attached to the rear. There are three different sensor packages, each providing a different set of sensors to detonate the mine. The Mk-62 is a "bottom mine," which is dropped in shallow water, and then detects a ship passing above using pressure (of the ship on the water), magnetism (of the metal in the ship's hull), or vibration. The sensor also comes with a computer, to enable the mine to follow certain instructions (like only detonate for ships that meet a certain criteria.)
The B-52 and B-1B drop the mines at an altitude of about 300 meters (1,000 feet), while moving at 500-600 kilometers an hour. The mines are usually dropped in known shipping lanes, especially those that serve as approaches to a major port. During World War II, air dropped mines proved devastating to Japanese shipping. Same thing when they were used against North Vietnam during the Vietnam War.
The B-52s were first equipped with anti-ship missiles (for testing) in the 1970s, and were given Harpoon missiles as regular equipment in the 1980s. But smart bombs have proved to be nearly as useful, and a lot cheaper than Harpoon. The B-52 was, until recently, the cheapest heavy bomber to operate, and favored for maritime patrol. But the B-52 is getting very old and more expensive to maintain. So now the B-1B is the low cost operator and the first aircraft when the air force is called to help out with sea control.