Emission-Free Wave-Powered Vessel Concept – All Comments Welcome

Hello everyone,

I would like to share a vessel concept for emission-free operation and without the need for fuel.
It is a wave-powered cargo system that I have invented and published openly under CC BY 4.0. I welcome comments from anyone — you don’t need to be an expert. Any thoughts, questions or ideas are appreciated.

The concept uses internal through-channels so that waves and ocean currents pass through the hull. Inside these channels there is a new specially shaped Archimedes screw that can take energy from the moving water.
The screw can also be used as a propeller, which increases the overall effect and makes the system hybrid.

The design includes:

a submerged cargo module for stability,

a passive stabilisation system for the "air-gap"

and an active ceramic coating (IAKKS) that protects all marine surfaces on the vessel, keeps them smooth, and provides an environmentally friendly antifouling effect for around 20-30 years.

The full description is published through Zenodo, which is an EU-funded research repository hosted and operated by CERN.
Here is the DOI link to the complete report and the technical annexes:

Zero-Emission Wave-Energy Vessel with Lift-Optimized Archimedes Screw Turbines, Ultra-Durable Marine Coating, and Passive Mechanical Rotor Stabilization https://doi.org/10.5281/zenodo.17552757

I would be happy to hear any thoughts or questions you may have. Feel free to share whatever comes to mind - all comments are appreciated.


Thank you,
Göran Skoog

 

How do you extract energy from current unless the vessel is anchored?

 

Good question.
As shown in the documentation, the ship sails in a zigzag pattern, as ships did in the past, to achieve the most optimal route possible.
Strong waves, such as those in the Pacific Ocean, have powerful currents that are almost constant and are below the surface. Turbines are arranged in rows at different depths.
A little further down, it is stable and calm, with the cargo serving as ballast.
The currents pass straight through the ship, creating a hybrid situation with waves above the surface and below. This provides stable operation as it passes through the ship. The resistance in the waves is transformed into propulsion.
Thank you for your question.

 

Everything that I'm aware of indicates that the energy available from wave action is Tiny compared to sails.

Never seen one with a screw turbine before, but my guess would be that energy is lost as compared to being propelled more directly by the wave energy. This link shows one of many possible ways to power more directly using waves, it even works going into the waves, instead of just with them.

 

Thank you for your comment — it’s a valid point and worth discussing.

It’s true that many traditional wave systems produce very little usable power, especially when the platform moves along with the surrounding water. In those cases the relative motion is tiny, and sails will always outperform them.

My concept is different in two important ways:

1. The vessel does not drift with the water.
It constantly adjusts its heading and crosses waves and currents at controlled angles.
This creates a steady relative flow through the internal channels, instead of relying on surface motion alone.

2. It is not only wave-powered — it also extracts energy from horizontal ocean currents.
Currents carry far more continuous energy than surface waves, and the vessel is designed so it never moves at the same speed as the water mass.
This ensures that the screw units always experience a real, usable flow through the channels.

Because of this, the turbines are exposed to two energy sources:

wave-driven oscillatory flow

and continuous horizontal current flow


This makes the system fundamentally different from a drifting wave device, and also different from surface-mounted mechanical arms.

Regarding losses: every system has losses, including the one in the link you shared.
The idea here is simply to place the energy extraction inside protected, controlled channels where lift-based rotation can operate more steadily and with less mechanical exposure.

I appreciate your thoughts — if you have ideas on the current-flow aspect or channel geometry, I would be glad to hear them.

— Göran

 

Yes, measurements would have to be taken in order to compare the losses of the screw turbine with the flapping fin, under carefully controlled outside conditions. Would one system have an advantage over the other if it hits floating debris or if heavy seaweed is present, and how much trouble is it to untangle?

How often, if any will the wave forces (from wind direction?) and current flow forces work against each other, or are they always perfectly aligned?

 

Thank you, these are important questions and exactly the type of practical considerations that need to be discussed.

On debris and seaweed:
One practical advantage of this concept is that the moving parts are located inside large-diameter enclosed channels, rather than exposed outside the hull.
Because the channels are wide, most things simply pass through without creating a blockage, and they encounter a smooth rotating surface instead of hinges or exposed mechanisms.

The internal surfaces use an active ceramic marine coating (IAKKS) which is extremely hard, tough and very smooth.
This reduces wear, prevents growth, and makes it harder for seaweed or soft debris to attach or entangle.

On wave forces versus current forces:
Waves and currents are not always aligned, and the system does not rely on perfect alignment.
The vessel maintains controlled angles so that a stable relative flow always passes through the channels — even when the directions differ.

It’s important to note that ocean currents are a continuous and steady energy source, unlike surface waves which vary over time.
This ensures that even when wave energy is low, the vessel still receives a constant flow through the channels from the current alone.

When wave and current forces work partly against each other, the relative flow pattern changes, but the system continues to operate.
This is something that would be measured in later testing.

Your questions are helpful for identifying what needs to be looked at more closely, so I appreciate them.

— Göran

 

This describes a perpetual motion system, which cannot exist. You claim it extracts energy to move by moving.

 

This is essentially the error with the concept.

It suggests something that cannot occur. The current cannot push the vessel in the opposite direction of the current. Consider a more stable current system, like a river.. There is no device that can oppose the current and travel against it using the power of the river.

If you created a device with a wide open throat that closed down to a narrower throat and increase the velocity of the current; the water could potentially turn a prop or turbine. But what happens in real life is the incoming current slows as the pressure increases. Drag enters the system and the rest is headed downriver. But rivers produce power!

I don’t profess much knowledge on hydrostatics, but the concept falls flat here. That said, a river could turn a turbine and charge a battery. That battery could in turn be used to propel a vessel forward. So, is that a perpetual motion machine? Not quite. The vessel would need to stop and recharge. Could more charging occur during the upstream travel? Yes. Would it be enough to become perpetual. No. Why? There are efficiency losses in power production that would be greater. Could the vessel sit and collect power for a day or some amount of time and continue? Yes.

Now, add mass. Cargo.

The power requirements to move up current increase. The amount of recharge time increases.

Perpetual motion? No. Current power collection? Yes.

In the open sea, another problem occurs. The vessel would need to stop for current collection. Dropping and raising anchor takes more power.

 

I think there is a misunderstanding here.
Nothing in my concept is based on perpetual motion, and there is no claim that the vessel extracts energy “from moving itself”. The energy input comes entirely from external wave forces.

A wave-powered system is no more a perpetual motion machine than a wind turbine or a tidal generator. It harvests energy from an environmental gradient – in this case the vertical and horizontal forces created by passing waves.

The principle is:

The vessel does not drift freely with the water mass.

It intentionally maintains a controlled heading relative to the incoming waves.

This creates relative motion between the hull and the water, which forces water through the internal channels.

The wave field supplies all the energy – not the vessel itself.


If the vessel were to drift perfectly with the waves, there would indeed be no usable energy.
But as long as the hull has a different dynamic response than the passing wave particles, usable energy exists. This is the foundation of every known wave-energy converter.

So the system is not “moving to create energy”.
It is moving because external wave forces act on it, and those forces are then harvested through controlled geometry.

There is no violation of physics here.

I hope this clarifies the principle.

 

Your objection is based on treating the ocean as a steady, unidirectional current.
That is not the environment the concept operates in. A river-flow analogy does not apply to an oscillatory wave field.

Let me clarify the physics.


1. Waves are not currents – they have oscillatory kinematics

In deep and intermediate water, wave particles move in orbital paths with horizontal and vertical components that vary in time:

u(t) = a \omega \cos(kx - \omega t), \quad
w(t) = a \omega \sin(kx - \omega t)

where group velocity and particle velocity differ significantly.

A vessel cannot follow these orbital velocities unless specifically designed as a Lagrangian drifter.
A large displacement hull will always have a different RAO (Response Amplitude Operator) than the surrounding water particles.

This RAO difference is the source of usable energy.

2. Relative motion is guaranteed by hydrodynamic response, even without anchoring

For any wave-energy device, usable power requires non-zero relative motion between:

the structure, and

the water particle velocity field.


Because the vessel’s RAO ≠ 1 for most frequencies, phase lag and amplitude differences create continuous relative velocity across the hull and internal channels:

u_{rel}(t) = u_{water}(t) - u_{hull}(t)

This relative velocity exists even when the vessel is free-floating.

This is standard hydrodynamics behind:

OWC systems

heaving point absorbers

attenuators

oscillating flap devices


None require anchoring to extract energy.


3. A river flow has no oscillatory forcing — ocean waves do

A river has:

steady-state velocity,

negligible horizontal acceleration,

almost no phase variation,

minimal pressure oscillation across the hull.


Therefore, extracting energy from a river while moving upstream is nearly impossible without anchoring.

Ocean waves, however, provide:

large pressure gradients,

cyclic forcing,

time-varying particle velocities,

non-zero mean drift forces,

and a significant difference between group velocity and particle velocity.


These factors enable continuous power extraction while the vessel is underway.


4. Wave power density dwarfs river power density

Deep-water wave power:

P = \frac{\rho g^2}{64\pi} H_s^2 T_e

Typical: 20–80 kW per meter wave crest.

River current power:

P = \frac{1}{2} \rho A v^3

Typical: 0.1–1 kW/m².

Your river argument underestimates available energy by two orders of magnitude.

5. The vessel does not “push against the current” — the wave field does work on it

The system is based on:

incident waves doing mechanical work on a non-drifting structure,

hydrodynamic added mass and damping creating phase differences,

pressure gradients driving internal flow,

conversion of wave-induced forces to shaft power.


There is no claim of extracting energy from the vessel’s own motion, and no violation of conservation laws.

The external energy source is the wave field.


Conclusion

Your critique assumes a steady-flow river system, but ocean waves are governed by oscillatory hydrodynamics.
When analyzed using RAO, wave kinematics and pressure forcing, the concept operates on the same principles as existing WEC technologies — none of which require anchoring or “stopping” to generate power.

There is no perpetual motion here, and no physical contradiction.

 

At what scale can your theory be tested?

Certain scaling must be required; otherwise the waves will act on the vessel easily.

But can you simulate ocean waves and current in an experimental state and do the tests in a lab?

 

Absolutely — scale testing is entirely possible, and the methods required are the same ones used throughout naval architecture and wave-energy research.

1. We use Froude scaling for any wave-dependent system

For devices influenced by wave forces, dynamic similarity is achieved by matching the Froude number:

Fr = \frac{V}{\sqrt{gL}}

This is the standard approach used for:

ship model testing,

wave-energy converters (WECs),

offshore platforms,

breakwater interactions.


So yes — the concept can be tested reliably at reduced scale.


2. Reynolds mismatch is acceptable in this regime

Most of the forces involved are dominated by inertia rather than viscosity, which is why traditional ship models work even when Reynolds numbers differ.

Wave-induced effects such as:

pressure variations,

orbital velocities,

added mass,

radiation damping,


scale correctly under Froude similarity.



3. Laboratory facilities can simulate realistic ocean conditions

Modern wave basins can reproduce:

regular and irregular ocean waves,

multi-directional sea states,

combined wave–current conditions,

different headings and loading scenarios.


Examples of such facilities include MARIN (Netherlands), NTNU (Norway), DHI (Denmark), and others.
A model at 1:20 or 1:30 scale would be entirely feasible.



4. What a test would measure

A controlled experiment could evaluate:

relative flow through the internal channels,

wave-induced pressure fields,

extracted mechanical power,

RAO curves (surge, heave, pitch, roll),

structural loads and damping effects.


These are standard hydrodynamic measurements performed routinely in wave-energy research.



5. Conclusion

Yes — the system can be tested at scale.
Wave-tank validation using Froude similarity is a well-established method, and the physics involved in this concept fit directly within that framework.

A lab test would provide clear insight into performance, efficiency, and optimization, just like any other wave-energy device or ship model.

 

Please don't try to confuse the issue with nonsense. This is not about big words or random pseudo equations. I am mechanical engineer and can follow fluid dynamics. However, build something and prove that existing science is wrong.

 

No worries — I'm not trying to confuse anything or challenge established science.
On the contrary, everything I described is based on very standard hydrodynamics used daily in naval architecture and wave-energy research. Nothing in the concept requires “new physics”, and I’m certainly not claiming that existing science is wrong.

The only point I intended to make is simply this:

wave–structure interaction is governed by oscillatory forces,

not steady currents,

and these forces can be evaluated at scale using the same methods applied to other wave-energy devices or ship models.


That’s all.

I fully agree that the real proof comes from physical testing.
Scale testing using Froude similarity is just the normal first step before any prototype work.
If the measured relative motion and pressure gradients are insufficient, then the idea fails — and that is fine.
If the results are promising, then it moves forward.

There is no disagreement with fluid dynamics here, and no attempt to “disprove science”.
Just an interest in evaluating a concept using the tools that already exist.