The Monitor was a highly modified version of the LCM-6 developed by the United States Navy for use as a mobile riverine assault boat in the Vietnam War.

The 81mm mortar was the only indirect-fire weapon fielded by River Flotilla 1 and, with the assistance of an artillery observer, could hit targets up to 4,000 yards (3,700 m) away.

The 40mm cannon was the only weapon in the Mobile Riverine Force's inventory capable of smashing mud bunkers, but the rounds tended to damage rather than destroy these fortifications, allowing the Vietcong to quickly repair and reuse them for future ambushes.

Commanders hoped the M132A1’s 32-second burst and 150 yards (140 m) range would not only neutralize enemy bunkers but also deter river ambushes.

Nicknamed "Zippo" after the popular cigarette lighter, these Monitors mounted two M10-8 flamethrowers, each with an effective range of 200–300 yards (180–270 m).

Sailors would make napalm by mixing a powder consisting of the coprecipitated aluminium salts of naphthenic and palmitic acids with gasoline.