Military History: The U.S. Navy’s “Douche” Boat Washed Away Viet-Cong Bunkers

In the early morning hours of June 10, 1969, U.S. Navy vessels sailed down a stretch of the Vam Co Dong River in South Vietnam. The force included a special weapon sailors called a “douche boat,” which could literally wash away Viet Cong fortifications.

“My assigned mission was to search out and destroy … bunkers, spider holes, trenches, booby traps and cashes [sic],” retired Master Chief Boatswain’s Mate Ray Longaker, Jr., who served for a time as commander of both of these craft, wrote in a message posted at WarBoats.org. “My crew and I did just that.”

And they did all this primarily with a high-pressure water cannon rather than some sort of gun or more traditional weapon.

In 1966, American and South Vietnamese forces were fighting for control of the Southeast Asian nation’s rivers and canals. Communist guerrillas routinely built fortifications and traps along vital routes to harass government forces and commercial shipping.

“The Viet Cong was … choking off the flow of rice to market,” according to an official U.S. Army history of the riverine campaign. “Far from being ‘totally cleared of Communist forces,’ … the delta was more than ever under Viet Cong control.”

In response, the top American command in South Vietnam proposed the ground and sailing branches partner up to take back control of these inland waterways. Better prepared for major battles on the open seas, the Navy quickly developed a fleet of smaller craft suited to this entirely different kind of warfare.

The sailing branch purchased newly designed river patrol and assault support boats to hunt down the enemy and patrol the brown waters. Command ships carried communications gear to coordinate the missions.

n addition, technicians converted World War II-era landing craft into armored warboats bristling with machine guns, cannons mortars, howitzers and even flame throwers. The biggest types were called “monitors” in reference to the American Civil War ironclad USS Monitor.

Other old landing craft became transports to ferry Army and South Vietnamese soldiers up and down the rivers. Some boats had helipads and medical facilities to treat troops wounded in battle.

But Viet Cong rockets, recoilless rifles and underwater mines were still a serious threat. The militants made homemade mines in a variety of sizes using whatever materials were available. American forces captured examples made out of sheet metal packed with nearly 290 pounds of TNT — more than enough to blow apart the relatively thin-skinned river boats.

“Booby traps consisting of hand grenades or B-40 [rocket] rounds with trip wires were discovered along paths from V.C. bunkers to the river,” an official Navy history recalled of one river mission. “Other booby traps were found which were designed to detonate as boats beached along the shore.”

And hidden inside mud bunkers reinforced with logs, insurgents were well-shielded from attacks. The earthworks often simply absorbed the explosive force of large caliber artillery shells and air-dropped bombs.

Enter the douche boats.

Read the Remainder at War is Boring