Concealed Carry: A History of the Hamilton Bomb Timer

In the 1960s, the Surface Warfare Center developed the 3801 Swimmer Weapons System for the Navy SEALs, a bevy of operational gadgetry that included Hamilton Bomb Timer, a discreet device capable of detonating explosives.

Daytime on the Ho Chi Minh trail. The rainy season. A Vietcong supply train emerges from the Annamite Mountains, bound for Kham Duc.

Curses ring out as one of the trucks — a boxy bastard borrowed from the Soviets — runs afoul of a rut in the corduroyed road. The convoy has no choice but to stop so the men can push the truck from the mire. It’s hard work, and the men are tired, their collars turned up against the rain, but they joke and pass a cigarette back and forth as they push.

One of men finds a canteen by the side of the road. Plastic, painted olive drab, U.S. military-issue — no doubt left there accidentally by an American G.I. The VC soldier looks at his own canteen, worn from years of use, and again at the one lying by the road.

He picks it up . . . and it explodes in his hand.

Hamilton 308 "Bomb Timer"

Hamilton 308 Bomb Timer

What he couldn’t see is what detonated the fatal blast: a watch attached to the explosive device hidden inside the canteen. Though it may seem like a prop out of a James Bond film, it was in fact a 308-6 device, one of a series of covert explosives made for the U.S. Navy at China Lake.

How each device worked was simple, almost elegant in its brutality: it was equipped with a connector plug attached to a timer.

Known as the “Secret City,” China Lake, California, has been the origin of almost every piece of airborne ordnance used by the U.S. military, and scores of other weapons we can only speculate about. Beginning in the late 1960s, the U.S. Navy instituted a project — the 3801 Swimmer Weapons System — to create weapons and materiel meant for use by the SEALs during the conflict in Vietnam. Booby-trapped canteens, cameras and machine-gun magazines were created there — even the green face paint that led the Vietcong to dub the SEALs “the men with green faces.” One hundred twenty-five of these “remote firing device models” were made at China Lake, then planted by those men with green faces for the enemy to find.

How each device worked was simple, almost elegant in its brutality: it was equipped with a connector plug attached to a timer. In the case of the canteen, the timer was a watch manufactured by Hamilton under a classified contract with the Navy. Like the explosive devices to which the watches were attached, they were indistinguishable at first glance from any other military watch with a 24-hour dial. 

After all, sometimes a watch is just a watch, and a canteen is just a canteen.

But the back of the Hamilton Bomb Timer hid its deadly secret. Two electrical contacts on the case back were concealed in plastic; once the plastic was removed, the contacts would be affixed to the blasting-cap lead and battery lead on the 308 device. The watch would then be wound and set to the local time, and when the hands reached 24:00 . . . well, remember that scene in Thunderball?

As one would imagine, few of these bomb timers survived the battle unscathed. Of the ones that weren’t detonated in combat, many were purposely destroyed in the late 1970s. Those that did remain? Testaments — vicious, inhuman, war-is-hell testaments, but testaments all the same — to the ingenuity of the men who designed, and those that put them to use.

Photo c. Atom Moore

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Christa Chance
Christa Chance

Christa was born and raised in Louisiana. In 2012, she moved to NYC from her hometown of Baton Rouge with just a suitcase. An avid watch collector and enthusiast from youth, she has worked for Vesper & Co., contributed to Hodinkee, is the Librarian/Recording Secretary of the Horological Society of New York and the Office Manager at Analog/Shift.

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