Complex sentence: To do that, John Latham and Stephen Salter proposed a fleet of around 1500 unmanned Rotor ships, or Flettner ships, that would spray mist created from seawater into the air.
Split into simpler sentences: To do that, John Latham and Stephen Salter have proposed a fleet of unmanned boats. Around 1500 unmanned Rotor ships, or Flettner ships, would spray mist created from seawater into the air.