About 21,000 DUKWs were built during World War II, which is 21,000 when 21,147 vehicles are rounded to the nearest thousand.
The DUKW was an amphibious adaptation of the GMC CCKW 2½-ton six-wheel-drive truck. Engineers enclosed the truck in a watertight hull, added a propeller and bilge pumps, and retained its road-going drivetrain. This combination allowed the vehicle to carry troops and cargo from ships to beaches, then continue inland without unloading everything onto a separate truck.
DUKWs became especially valuable in amphibious logistics. They could load directly from landing ships, cross water, climb beaches, and distribute supplies on roads or rough ground. Their work supported Allied operations in Europe and the Pacific, while Britain and other Allied forces also received vehicles through Lend-Lease. The nickname “Duck” came from the vehicle’s DUKW designation and amphibious character.
The exact figure matters because the question asks for a rounded total: 21,147 is not rounded to 20,000 or 22,000 under the nearest-thousand convention; it becomes 21,000. DUKWs were transport vehicles rather than tanks, though some received ring mounts for .50-caliber machine guns for local defense.