Just as the topic, I am not that informed but my understanding is that the start of D-day was those small ships packed with soldiers being dropped close to the beaches. Why didn't the allied instead just drop armored vehicles?
It did, Duplex Drive Sherman tanks were used in the first waves on all five beaches, with varying degrees of success in choppy water. Tanks have to be supported by infantry to be effective, this is especially true for the breakout from the beaches where infantry was much more effective at clearing defensive positions and obstacles. A first wave made up entirely of tanks wouldn't have been effective.
