What is the smallest size vessel that can be detected?

Planet can detect vessels down to about 10 m in size (~3 pixels). Small islands, waves, and clouds could easily be interpreted as small boats (even by the human eye) and particularly on cloudy days or rough sea states. The bigger the vessel is, the higher the likelihood that it will be accurately detected. Vessels in the 10-30 m range will be detected with varying accuracy, while vessels greater than 50m will return higher performing results.