Wednesday, July 18, 2007

DuKWs and Barrage Balloons

The Amphibious Truck. (DUKW)
The DUKW was used in landings on the D-Day beaches of Normandy.American crews in DUKWs,carried 18 million tons of supplies ashore in the first 90 days after the initial assault.This is more tonnage than all the combined British Services brought ashore for the remainder of the year.This is an important statistic because the British spent more than 2 years building The Mullbury Harbors, most of them destroyed by the weather or lost by shameful handling with a dear cost of lives. Some of the DUKWs  specifications were;
Weight 6 Ton (12,000 lbs) Length about 30 feet. Width 8 ft Height 8 ft with a crew of 2.
Built by GMC it has a range of 350 km (road), 70 km (water) Speed 50 mph on land...and 7 to 9 Knots in the water.
When a United States Coast Guard patrol craft ran aground on a sandbar a few years before the war, it stranded seven Coast guardsmen near Provincetown, Massachusetts.
A new experimental DUKW happened to be in the area.
Winds up to 60 knots (110 km/h), rain, and heavy surf prevented conventional craft from rescuing the Coast Guardsmen, but the DUKW had no trouble. The DUKW would later prove its seaworthiness by crossing the English Channel.
The DUKW prototype was built around the GMC,six-wheel-drive military truck, with the addition of a watertight hull and a propeller. The vehicle was built by the GMC division of General Motors at the beginning of the war. It was powered by a Straight-6 engine.
More than 21,000 were manufactured. It was not an armored vehicle, being plated with sheet steel between 1/16" and 1/8" thick to minimize weight. A high capacity bilge pump system kept the DUKW afloat if the thin hull was breached by holes up to a couple inches in diameter.
The DUKW was the first vehicle to allow the driver to vary the tire pressure from inside the cab. The tires could be fully inflated for hard surfaces such as roads and less inflated for softer surfaces—especially beach sand. This added to the DUKW's great versatility as an amphibious vehicle. This feature is now standard on many military vehicles.
During the initial landings, most Liberty Ships and almost every large vessel, had a barrage balloon, overhead, suspended by a steel cable some 3 to 4 hundred feet in the air above it.
These huge balloons were about 40 feet long and were supposed to deter low flying enemy aircraft.
Fortunately, the absence of enemy aircraft can be attributed to the excellent results of the U.S and the Royal Air Forces.
These balloons were overhead for the few days before and at the beginning of the storms but they quickly disappeared after the first
3 weeks. They were winched in and discarded.
New vessels coming to the beach after then, no longer sported Barrage Balloons