Analytical look at propeller-free propulsion concepts, including the patented work of Iranian-German inventor Mohsen Bahmani.
As the global transportation sector accelerates toward decarbonization, maritime shipping faces mounting pressure to evolve. Cleaner fuels, electrification, hydrogen, ammonia, hybrid propulsion, and smarter vessel design have all become central to sustainability discussions. Yet one of the most fundamental engineering assumptions in marine transport has remained largely untouched: the propeller.
For over a century, propeller-based propulsion has powered everything from cargo ships and ferries to naval vessels and offshore platforms. It is proven, scalable, and deeply optimized. But sustainability in modern transport is no longer measured by fuel consumption alone. Increasingly, it is defined by a broader set of variables: lifecycle efficiency, maintenance burden, acoustic pollution, mechanical durability, environmental disturbance, and long-term operational resilience.
This raises an important question: can maritime transport become meaningfully more sustainable if propulsion architecture itself remains unchanged?
Sustainability at Sea Is More Than Emissions
The maritime sector often frames sustainability through the lens of carbon reduction. That focus is justified. International shipping remains one of the world’s major contributors to transport-related greenhouse gas emissions, and regulators are pushing aggressively toward cleaner operational models.
But emissions are only one part of the equation. Sustainability in marine transport also includes underwater noise pollution, maintenance intensity, infrastructure efficiency, operational reliability, and the ecological footprint of mechanical systems themselves.
A vessel powered by cleaner energy but still dependent on noisy, mechanically intensive, high-maintenance propulsion may represent only partial progress.
The broader question is not simply what powers ships but how efficiently, quietly, and sustainably thrust is generated in the first place.
The Propeller’s Strength and Its Structural Limits
There is a reason the marine propeller remains dominant. It is one of the most refined propulsion technologies ever developed. Highly efficient at scale, mechanically mature, and globally supported by manufacturing ecosystems, the propeller remains extraordinarily difficult to replace.
But even optimized technologies carry trade-offs.
One of the most significant is cavitation, the formation and collapse of vapor bubbles around rotating blades. Cavitation reduces propulsion efficiency, accelerates wear, generates vibration, and contributes significantly to underwater acoustic pollution.
This matters far beyond engineering.
Marine noise is increasingly recognized as an environmental issue, affecting whale communication, fish migration, and broader ocean ecosystems. Sustainability in shipping is no longer only about carbon emissions, it increasingly includes ecological disturbance.
Traditional propulsion systems also require shafts, seals, bearings, alignment systems, maintenance infrastructure, and periodic component servicing. Over long operational lifecycles, these factors shape both environmental and economic sustainability.
Alternative technologies such as podded propulsion, waterjets, azimuth systems, and rim-driven thrusters attempt to improve certain aspects of conventional design. But most still operate within familiar propulsion assumptions.
Does Sustainable Innovation Require Architectural Rethinking?
This is where the sustainability discussion becomes more interesting.
In most industries undergoing decarbonization, innovation initially focuses on cleaner energy inputs. Only later does deeper architectural redesign emerge.
Maritime transport may be approaching that second phase.
If sustainability means more than fuel substitution, if it also includes durability, noise reduction, environmental compatibility, and lifecycle efficiency, then propulsion architecture itself becomes a legitimate area of scrutiny.
Among the more unconventional concepts relevant to that broader discussion is work by Iranian-German mechanical engineer Mohsen Bahmani, whose engineering focus has centered on alternative propulsion architectures. A graduate of the Karlsruhe Institute of Technology (KIT), Bahmani’s work has explored system-level propulsion redesign rather than incremental optimization of conventional mechanical formats.
One of his most notable developments is a European-patented propulsion concept that proposes an alternative to traditional exposed propeller-based thrust generation. Rather than relying on a conventional rotating propeller, the architecture organizes multiple propulsion elements within an enclosed coordinated system designed to generate thrust through controlled motion cycles while remaining grounded in established reaction-based physics.
Its relevance to maritime sustainability is not that it offers an immediately proven replacement for marine propulsion, but that it reflects a broader engineering question: whether future sustainable transport systems may benefit from fundamentally rethinking how thrust is structurally produced, particularly in environments where noise, mechanical wear, safety, and environmental interaction are increasingly important.
Sustainability Requires Skepticism
Novel propulsion concepts often sound compelling in principle, that is not the same as practical sustainability.
Marine propulsion is among the harshest engineering environments in transportation. Saltwater corrosion, continuous duty cycles, thermal loads, biofouling, reliability demands, and scale economics create exceptionally high barriers to adoption.
Any alternative architecture must compete against technologies that have been refined over decades.
This includes difficult engineering realities:
• Efficiency under sustained operation
• Thermal management
• Manufacturing complexity
• Long-term reliability
• Scalability from concept to industrial deployment
• Maintenance economics
A propulsion concept that appears architecturally elegant but consumes more energy, introduces hidden inefficiencies, or proves difficult to certify would weaken rather than strengthen sustainability outcomes. Innovation alone is not sustainability. Measured lifecycle performance is.
The Hidden Sustainability Opportunity
Still, there is a risk in assuming that mature technologies represent the endpoint of optimization.
History suggests otherwise. The shipping industry often focuses intensely on fuel pathways, hydrogen, ammonia, methanol, electrification, but propulsion architecture itself may remain an under-explored variable in long-term sustainability.
If future propulsion systems can meaningfully reduce:
• Cavitation-related losses
• Underwater acoustic pollution
• Exposed mechanical wear
• Maintenance intensity
• Ecological disturbance
• Integration constraints for autonomous or next-generation vessel designs
Then the sustainability conversation could expand beyond emissions in meaningful ways.
That does not mean conventional propellers are obsolete, but it does suggest that sustainable maritime transport may ultimately require broader engineering imagination than fuel substitution alone.
The Bigger Question
The marine propeller remains one of the most successful engineering solutions in transportation history.
Replacing it would require extraordinary justification.
Yet sustainability transitions rarely come from improving only one variable.
Sometimes they come from questioning assumptions so deeply embedded they no longer appear open to reconsideration.
The future of sustainable maritime transport will almost certainly be shaped by cleaner fuels and smarter vessels. But it may also depend on whether propulsion architecture itself is ready to evolve.
Resources
Patent certificate:
- https://worldwide.espacenet.com/publicationDetails/biblio?FT=D&locale=en_EP&CC=EP&NR=3565971B8&KC=B8
- https://pubchem.ncbi.nlm.nih.gov/patent/EP-3565971-B8
- https://patents.google.com/patent/EP3565971B8/e
New Propulsion System 2025:
Video 1: https://youtu.be/jOcQJzqZFws
Video 2: https://youtu.be/Io3yHXm8AjA
Wochenblatt: https://www.wochenblatt-news.de/ueberregional/bahmani-revolutioniert-die-antriebstechnologie/
https://londondailypost.co.uk/mohsen-bahmani-introduces-a-revolutionary-propulsion-technology/
E-Plan Aerospace: https://www.eplaneai.com/news/iranian-inventor-develops-propeller-free-propulsion-system-for-flying-taxis
