Secret testing of a revolutionary ‘smart-bomb’ device during World War II gave area residents a start — and the U.S. a key advantage

By Michael A. Hamilton and George W. Contant
Photograph courtesy of the Applied Physics Laboratory, Johns Hopkins University
From the May 2014 issue

ftmilesDuring World War II, Fort Miles guarded the entrance to Delaware Bay with a wide variety of coastal defense guns, including huge 12- and 16-inch behemoths — the sort that battleships fired to such devastating effect. With all that firepower so close by, it’s no wonder people in Lewes and Rehoboth Beach were often jarred in their homes by the thunderous sound of heavy weaponry.

Except, those monster guns were actually fired just a few times, and that was for testing. So what was the source of all the booming that locals used to complain about? The answer lies in the fact that from January 1944 to September 1945, some 150,000 artillery shells were indeed fired from Fort Miles — an average of 180 per day, or 2,000 per week — but it wasn’t the fort’s defensive guns that were firing, and they weren’t shooting at some enemy. These rounds all emanated from a highly classified area of the fort known to the locals as Herring Point, but to the U.S. War Department and dozens of high-level civilian scientists as the Ordnance Research Center–Fort Miles Section.

 What, precisely, was going on? The shells were fired as part of a top-secret program that, according to none other than Gen. George S. Patton, was second in importance only to the atomic bomb. The thing being tested was known as the proximity, or variable-time (VT), fuze — the world’s first “smart bomb.” (And yes, for you civilians, it’s f-u-z-e.)

What was the big deal about this “funny fuze,” as Patton once called it? Using experimental radio technology, shells armed with the proximity fuze sent out radar-like radio waves that bounced off objects — planes, tanks, even the ground. As the round got closer to the object, the pulses received back by the fuze would become strong enough to detonate it, usually within 75 feet of the target. Suddenly, direct hits on a target were no longer necessary, making artillery of all kinds exponentially more effective. Patton would later gush about this “game changer”: “I think that when all armies get this shell, we will have to devise some new method of warfare. I am glad you all thought of it first,” he said to Army Chief of Ordnance Levin Campbell. (Well, not quite first. Britain, Germany and Japan were all spending considerable resources to develop such a device too, but the U.S. succeeded first.)

To explore the development of this weapon further, some military alphabet soup is in order. Though it was originally a Navy project, the Army quickly saw the potential, and charged its Ordnance Research Center (ORC) at Aberdeen Proving Ground (APG), in northeast Maryland, with the research and development of the VT fuze for use with Army guns and howitzers. The ORC established several locations to conduct the mission, including Fort Miles, which it dubbed the ORC-FMS (Fort Miles Section). Then, in early January 1944, the ORC-FMS Ordnance Test Group (OTG) arrived at Fort Miles. That arrival must have attracted a lot of attention as trucks towing 75 mm pack howitzers rolled through the fort’s front gate. Later, 105 mm, 155 mm, 8-inch, and 240 mm howitzers, and a lone Navy 5-inch/.38-caliber gun would follow.

Equally remarkable, the OTG (a 34-man unit) carried Thompson submachine guns, and apparently no one seemed too concerned about standard military “spit and polish.” They were commanded by a Capt. W.L. Thomasson, with a Lt. J.W. Shoemaker as Navy liaison officer. Their highly classified mission was to fire artillery rounds equipped with the VT fuze to confirm its reliability and effectiveness prior to its introduction in land combat.

Members of the OTG had their meals with the 21st Coast Artillery that was responsible for the fort’s sea mines. But they must have felt like stepchildren because they were quartered in single-story concrete barracks that had three potbelly coal stoves and no latrine, while the men in the 21st lived in standard two-story barracks with an inside latrine and heat from a furnace. The OTG newcomers reportedly never felt accepted by the men of the Coast Artillery, but it couldn’t have been otherwise. They were from a different branch of the Army and their mission was a secret they could not share with anyone outside their unit.

Soon a complex of new construction sprang up just below Battery Herring (a gun emplacement), including a special L-shaped safety revetment (or protective enclosure), the base of which was set against the ocean. It was 100 feet long, 25 feet high, 8 feet wide at its base and 4 feet at the top, and constructed of wood and filled with sand. Running through it were small pipes that housed long lanyards used to fire the artillery from a safe distance. This safety feature proved its worth many times over as the tested fuzes often discharged too early, causing the artillery round to explode within several feet of the muzzle.

Additional infrastructure was constructed at Fort Miles specifically to support the program, including four ammunition storage igloos, an ordnance magazine and a loading facility. However, the ammunition igloos were either not used, used only for gunpowder bags, or otherwise filled beyond capacity, as all the ammunition (except the fuzes) was actually stored in the open among the sand dunes. An ordnance magazine was constructed south of Battery Herring, within 100 yards of the OTG firing line. The fuzes for ammunition up to 105 mm were installed at the magazine. Larger calibers had their fuzes installed at the firing line.

These fuzes were so secret they were delivered every day by a heavily guarded train to Georgetown and then picked up by a submachine-gun-armed OTG team, which transported them to Fort Miles. They would receive the exact number and type of fuzes scheduled to be fired that day, take them to the ordnance magazine and then fire them, the idea being that none of the special fuzes would be stored overnight and thus become subject to special security requirements. Occasionally there was no choice but to do just that because of some unforeseen event such as bad weather, which prevented the required observation of the rounds as they were fired. When this happened, the fuzes were stored in a casemate (a shellproof armored enclosure) protected by a steel door with three locks and guarded by three OTG sentries. It is likely that the casemate was Battery Herring itself. The Thompson-armed guards spent two hours on and four hours off until the fuzes could be fired at the first opportunity to do so. On one occasion the weather cleared at 5:30 on a Sunday morning and the OTG found itself bombarded by complaints from Rehoboth citizens who didn’t understand why Fort Miles had to fire its guns so early on a weekend morning. (The men of the OTG had little sympathy; they had already been awakened much earlier to prepare for the firing.)

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