Yes there is supposed to be no input. There is a lot more energy lost from the motion of waves and tides from destructive interaction. Waves can dissappear, the tides are diverted and disrupted. If you threw a rubber ducky in the drink would it move for ever.Perpetual motion is impossible.I can understand that one may see the tides as having an external energy source making them not perpetual in motion but if we look at the solar system as a whole we have many parts just as an inventor of a so called perpetual motion machine will include many parts. It is said that true perpetual motion must put out more than is put in and if we take the moon example the moon can not push us over but an ocean wave can the wave has more authority over us than the energy that produced it.
The tides are possible.
The tides are not perpetual motion.
If you point out facts to Petrochemicals, after a while, he puts you on his ignore list.
Presumably, this is to stop him having to think