When the Zeonic Company's amphibious MS-06M Zaku Marine Type proved a failure, the Zimmad Company stepped in to take a new approach to the challenge of underwater combat mobile suits. As the Principality of Zeon was desparate to keep their foothold on Earth during the One Year War, they needed an effective way to operate in Earth's oceans. The Zimmad Company's first - and successful - design was the MSM-03 Gogg. Heavily armored to withstand deep sea pressures, and with the sea to act as a natural heat sink, its bulky body housed a large and powerful reactor - large enough to power the Gogg's built-in beam weapons. Being a submersible unit, the Gogg's body also contained ballast tanks, whose water could be used to radiate reactor heat when it operated out of the water in amphibious assaults. With these features, the MSM-03 Gogg was the first "true" amphibious mobile suit and would set the stage for all underwater combat suits to come.