The most effective tidal pump IMO would be a tethered float with a deep anchor and you would use both the vertical and horizontal movements, the latter being much larger from tidal flows. A 600m cable to the bottom and therefore to your pump is not impossible. However the net ocean current may not reverse, so you need to choose a point where there is a major tidal reversal.
sicut vis videre esto
When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
Originally Posted by Ken G