As mentioned in a related entry, the American were the first who during the Second World War approached the problem of amphibious operations in a serious way. The rediscovery of amphibious means was, without any doubt, a notable step toward the solution of the problems related to the transfer of troops from the ships to the landing beaches; however, while the results of the different LST and LCT were good, as it often happens at the moment of truth, new problems arose, of which nobody had thought before. First of all, the slow and vulnerable amphibious vehicle, after having downloaded her load, should return to the starting point in a continuous labor of transporting troops to land. This exposed her to passing repeated times through the most dangerous areas, with great chances of being destroyed. Moreover, when the vehicle carried the soldiers of the first landing wave, as soon as the fore gate was opened the troops were left at the mercy of the enemy, even if this one was only one man, who, being in front of a mass of disorientated and often dizzy men, who were crowded in such a small space, could play havoc with a simple rifle. To this was added a particular problem of the scenario where the American operated, especially during the first part of the war: the presence of coral banks in the atolls where landings were more frequent. These banks, which suddenly limited the depth of the water to just some decimeters, often forced the landing craft to stop long before reaching the beach. The soldiers, overladen with weapons and ammunitions, had to jump to the water to walk toward the area where the beachhead was. Many of them drowned and others were hit by the enemy fire before reaching the shore. It was then decided to build a vehicle capable of overpassing the coral banks and transporting the soldiers to land, while supporting them, if necessary, with the fire from the onboard weapons. This way a new type of equipment, denominated Landing Vehicle Track, was born. The formula had such a success in the front of the Pacific, despite of a disastrous and dramatic debut, that 18620 LVT of several types would be built before the end of the war. One of the best series was the third one, of which 2962 units were built by two companies based in Michigan: Graham Paige Motor Corporation of Detroit and Ingersoll Steel & Disc Division, an associate of the Borg Warner Corporation of Kalamazoo. These vehicles, denominated LVT 3 and nicknamed as "Bushmaster" (the American name of a venomous rattlesnake which is widely spread on tropical areas), granted their optimal services in every front in the Pacific until the last days of the conflict. The main innovation of the "Bushmaster" was the utilization of tracks of hull-enveloping type. These, besides allowing to overpass submerged obstacles, provided the movement in the water, thanks to a certain number of ribs in their outer face which actuated like paddles or oars, a system which was later adopted by many modern amphibious tanks. The access ramp was located in the rear part, so that the soldiers could leave the craft with a lesser danger. The "Bushmaster" could transport up to 4.5 tonnes or 30 to 40 fully equipped men. A light armor provided enough protection and the armament ranged from one to four 12.7-millimeter machine guns. After having served for transportion, it often remained in the place to serve as support vehicle. The "Bushmaster" remained in service many years after the war and it was delivered to many countries.