You go to war with the design trade-offs you planned, not the design trade-offs you discover you need

From Citizen Soldiers by Stephen E. Ambrose, page 65.

To paraphrase Rumsfeld, you go to war with the design trade-offs you planned, not the design trade-offs you discover you need.

Thanks to the American productivity and ingenuity, there were many more Shermans in action than Panthers or Tigers (in fact, about half the Wehrmacht's tanks in Normandy were Mark IVs, 26 tons). Besides numbers, the Shermans had other advantages. They used less than half the gasoline of the larger tanks. They were faster and more maneouvrable, with double and more the range. A Sherman's tracks lasted for 2,500 miles; the Panther's and Tiger's more like 500 miles. The Sherman's turret turned much faster than the Panther's or Tiger's. In addition, the narrower track of the Sherman made it a much superior road vehicle. But the wider track of the Panther and Tiger made them more suited to soft terrain.

And so it went. For every advantage of the German heavy tanks, there was a disadvantage, as for the American medium tanks. The trouble in Normandy was that the German tanks were better designed for hedgerow fighting. If and when the battle ever became mobile, then the much despised Sherman could show its stuff.

American transport and utility vehicles were far superior to the German counterpart. For example, the jeep and the deuce-and-a-half truck had four-wheel-drive capability, and they were more reliable than the German vehicles. But again like the Sherman, their advantages did not show in the hedgerows, where squad squad size actions predominated and the mass movement of large numbers of troops over long distances was irrelevant.

With any weapon, design differences lead to losses as well as gains. The German potato masher, for example, could be thrown farther in part because it was lighter. It had less than half the explosive power the American grenade. The GIs said it made more noise than damage.

One other point about weapons. Over four decades of interviewing former GIs, I've been struck by how often they tell stories about duds, generally about shells falling near their foxholes and failing to explode. Lt. George Wilson said that after one shelling near St. Lo, "I counted eight duds sticking in the ground within thirty yards of my foxhole." There are no statistics available on this phenomenon, nor is there any evidence on why, but I've never heard a German talk about American duds. The shells fired by the GIs were made by free American labor; the shells fired by that Wehrmacht were made by slave labor from Poland, France, and throughout the German Empire. And at least some of the slaves must mastered the art of turning out shells that passed examination but were nevertheless sabotaged effectively.

Heartrending to think of the German slave-laborers, risking their lives in sabotage and never knowing just how many American lives they were saving, and correspondingly, the American soldiers never knowing the brave actions taken on their behalf by unknown Europeans subjugated to the German war machine.