The USMC went into WWII relatively unprepared when it came to using tanks. It was not really seen as a major requirement for the Corps and they were quite limited by what would work by the ability to get these tanks from ship to shore. Their first practical tanks were license built Renault FT 17s which were used for many years and of which the Marines had only a couple of handfuls. This was replaced by the newer, but rather unreliable Marmon-Herrington light tanks. These were eventually used in what became backwater places like New Caledonia for defense in case the Japanese came calling. They landed on Guadalcanal in 1942 with M2A1 light tanks and found that even in thick jungles, these tanks were quite useful in a rather limited way. Mostly for infantry support, in fact, the Marines only fought one tank battle of any consequence the whole war and that was on Saipan.

But getting back to the jungles of Guadalcanal, it was here that the USMC learned how to use their tanks. They were effective against Japanese fortifications, despite being unable to be easily maneuvered. The Corps also got M3 and M5 light tanks to use later during the jungle campaigns in the Solomons, including the long campaign on Bouganville. The M4 Sherman series was used in later landings in the central Pacific and the increased firepower was greatly appreciated. One of the situations that had to be addressed is that often these tanks were set on the coral reef a considerable distance from shore so efforts were made to waterproof these tanks as much as possible. Of course, that did not help when the tank fell into a shell hole!

The Japanese were quite adept at using satchel charges and magnetic mines against these tanks so ways were developed to reduce their effect. The exterior of the hull was often plated with wood and that took care of the magnetic mine situation. Variouis screens and barbs were put on the upper surfaces so that satchel charges would not blow up directly against the hull. Not much could be done against mines and in some island fighting, that was a major problem. So was the Japanese 47mm anti-tank gun that was used later in the war.

As infantry support was the main reason for these tanks, it was important to be able to talk to the infantry so many Shermans carried two radios with one tuned to infantry frequencies. They also developed the use of external phones that were hooked into the crew ICS. These were in packs on the rear of the tank so a soldier could just grab it and talk directly to the crew. Of course, when M4s battled Japanese tanks it was generally a slaughter for the Japanese as Japan's tank development seemed to have been stalled out in the late 1930s and their tanks were woefully inadequate in all abilities. There is quite a bit more to this one including the development and use of flame throwing tanks, but I will leave that for you to discover when you read this one.