Technically, Einstein, energy and mass are just two different manifestations.
But, no, a "breakwater" exclusively uses the mass inherent in the physical earth upon which it is attached to counteract ("break") the water. That's why the breakwater doesn't float away ... because it is ATTACHED.
Otherwise, any floating object you want to name the SS BREAKWATER would need to have more mass than could possibly be moved by the energy contained within surface waves.
And, since entire coastlines are destroyed by surface waves impacting upon the earth, one can assume your SS BREAKWATER would need to be extremely massive if you don't want the SS BREAKWATER to be pushed around (eventually colliding with land) in the open sea.
If you want to break water on the open sea, either attach your "breakwater" to the earth under the sea OR create such a massive structure that your SS BREAKWATER is effectively considered an "island" in itself ... which negates entirely your purpose of creating a "breakwater" to protect the seastead.
Please stop trying to argue to win your point, @Georgeb, and consider the thing you are trying to accomplish.
You want to capture energy from surface waves.
Creating a massive structure (breakwater) merely to capture a lesser amount of energy than is necessary to build and maintain the breakwater is a foolish exercise.
Concentrate on the portion of your proposal that CAPTURES energy by somehow transferring it into your electrical generation plan. THAT has potential.
But transferring the energy contained within a surface wave into your massive structure called "breakwater" is a wasted transfer because, to get energy back from that structure, you'll need to consume energy by lifting (and then letting gravity drop ... so that now "energy capture" can finally create electrical power) a portion of the structure, itself.
You want to create a floating platform to lift water and subsequently create electrical power when gravity pulls the lifted water downward.
THAT is not a "breakwater".
From an entirely different perspective, there is a need to eliminate swells (created by surface waves) from under a floating seastead. A "breakwater" does not do THAT, unless the mass of the structure is large enough to oppose all of the open-sea forces of surface waves.
But DISSIPATING the energy (aka, surface waves) eliminates the swells, regardless of the dissipation method.
Problem of swells is gone when the surface wave no longer exists. The seastead floats on a smooth surface. Problem solved.
How to BEST deal with the surface wave is the community's question.
The "Wave Bridge" theoretically might work, but there is no other benefit to the community.
Energy transfer in an electrical generation scheme would work to minimize or eliminate swells ... AND it would have the benefit of generated electricity.
But if MASS is first necessary as a platform to capture electrical energy, then some energy transfer is wasted.
The "breakwater" is mass.
However, if virtually ALL of the available energy (aka, surface wave) was dissipated (by electrical generation or some other dissipation mechanism), then there remains no surface wave to produce any swells.
As previously noted, a massive oil slick would do that via gravity.
A very large floating kelp bed or a mangrove forest would also work to dissipate the surface waves, as would a properly designed semi-submerged scaffolding barrier.
And, yes, a very massive SS BREAKWATER the size of a small island would work ... but only if its horizontal distance parallel to the surface wave's direction was large enough to absorb the surface waves peaking underneath it ... AND only if that SS BREAKWATER island was structurally sound enough to not be torn apart by that constant pounding.
But simply floating a narrow structure that resembles a coastal breakwater is an idiotic attempt to "break water" on the open seas ...
... because coastal breakwaters rely upon the mass of the Earth to oppose the ocean's energy.
One need not be as smart as Einstein to figure that out. Just go watch a boat crash into a breakwater and observe which one wins.