Complex sentence: In 2011, March began developing a more reliable amphibious vehicle using technology from The Python and his other prototypes, and in June 2013, released The Panther: the first commercial vehicle developed by WaterCar.
Split into simpler sentences: In 2011, March began developing a more reliable amphibious vehicle using technology from The Python and his other prototypes. In June 2013, March released The Panther, which became the first commercial vehicle developed by WaterCar.