I'm not sure we are communicating clearly, @Georgeb.
A surface wave is a specific type of wave that exhibits specific properties. It has an amplitude that equals only 1/2 the distance from crest to trough ...
... and, therefore, the water just below the trough is, for all practical purposes related to seasteading, undisturbed by the surface wave.
ALL issues on the open sea, related to that energy, happen between the crest and the trough. Unless one plans to locate a seastead in the shallow water of a coastal area, discussions of friction and surf are irrelevant.
Further, the energy of the surface wave - on the open sea - doesn't dissipate by friction or spreading out. The surface wave travels in a directional line and changes direction by refraction. This is how traditional Polynesian sailors navigate ... by knowing the locations of islands and the directions of surface waves created by the prevailing winds, and calculating their location relative to the surface waves that are refracted from those islands.
The surface wave dissipates by lifting water, forming the swells, as it travels across the open water. Formed by surface winds, the surface wave is either reinforced/maintained by more wind OR it dissipates by fighting against gravity as it lifts water into swells.
On the open sea, any proposed "breakwater" would be a floating breakwater ... which is any oxymoron.
So your proposal - of lifting water into storage tanks - must deal with only that narrow depth of water contained within the range (2 x amplitude) of the surface wave. Below that range (i.e., below the trough) there is virtually no convertible surface wave "energy".
This comment thread is a conflation of two basic concepts - surface waves and breakwaters - that must be dealt with differently on the open sea, as compared to a place (shallow water or shoreline) where a breakwater will work because it can be physically connected to land.
Other threads have, in the past, conflated "breakwater" with efforts to deal with the problems of surface waves on the open sea ... and those are DIFFERENT problems requiring different solutions.
Breakwater deals with mass ... what to do about surface waves on the open sea is strictly an energy problem.
Consequently, on the open sea, creating electricity from any form of surface wave capture is really just a matter of deciding which project has the best cost-to-build-and-maintain ratio as compared to electrical production.
The conclusion MIGHT be another form of energy production (solar, nuclear, etc.) or it might be your plan.
And kudos to you, George, for thinking of ways to create a potential solution.
My purpose is not to criticize your plan, but to point out that this comment thread was using similar words to mean different things and conflating a near-shore issue with an open-sea issue.
Your 'vertical storage' idea has some merit - and alternative applications, btw - so I wasn't trying to discourage your brainstorming.
But this (TSI) forum has traditionally mixed up vocabulary and meaning within the same comment threads, leading to confusion. I was trying to point out that this thread had taken a similar turn.
Regards, and thanks for "floating" your idea for everyone to consider.