The waters were shallow, so torpedoes would hit the bottom and fail to do any damage. On top of that, Japan was 4,000 miles away from Pearl Harbor, a next to impossible feat in those days. But, Pearl Harbor was still the best choice. The torpedoes were solved by adding wooden fins to the ends. This way the torpedoes angled to their target before they hit the bottom. This was a good solution. Japan had an almost exact replica of Pearl Harbor, another reason to pick Pearl Harbor. If the torpedoes worked here, they would work there.
But how to get to the harbor? Yamamoto had an answer. Aircraft carriers would carry the planes to a point where they could go, attack, and then come back. This was a good solution but posed another problem. America was sure to have spies in Japan. It would be foolish not to. How would you get the aircraft carriers away without being seen by American spies? Simple! They would leave one by one and meet up at an island north of Japan. This island was safe from prying eyes, and the planes would still have enough gas to make it back to the