Propeller Energy Saving Devices Patents: Top Companies & Trends 2026
- Concentrated at the top. The five leading assignees hold 115 of 211 records in scope (54.5%), and the leading ten hold 163 (77.3%) — a field with a short list of repeat filers and a long tail behind them.
- Filing has cooled from its 2018 peak. Annual filings peaked at 7 in 2018 and have declined since; the 2021-to-2024 span alone shows a drop from 4 to 2 filings, a 50% fall over that window.
- Classification spreads well beyond the hull. 43.6% of records sit in B63H marine propulsion, but sizeable shares also fall in electric measurement (19.4%) and power supply systems (17.5%), pointing to instrumentation and control as much as blade geometry.
Filing growth compares 2021 (4 records) with 2024 (2) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 211 records in scope (CR5), not by the ranked leaders only.
What propeller energy saving device patents actually cover
Propeller energy saving devices sit at the intersection of hydrodynamics and retrofit engineering: fins, ducts and boss caps fitted ahead of or behind the propeller to recover rotational energy lost in the slipstream. The search scope used for this landscape pairs core hardware terms — energy saving device, propeller boss cap, ducted propeller — with the physical mechanisms that justify a filing: wake field correction, hub vortex suppression, cavitation risk, and the model test and scale correlation work needed to prove a design before it goes on a hull.
That pairing matters for scope discipline. A device claim without an accompanying wake-field or model-test limitation tends to sit on old, heavily cited prior art from the 1980s and 1990s boss-cap-fin era; claims that tie the mechanical structure to a specific measured flow condition or scale-correlation method are the ones doing useful work in this dataset.
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Filing trend and technology composition
211 published records fall inside the search scope across the 2015–2026 window (publication lagging filing by roughly 18 months, so the most recent one to two years are always undercounted). The two views below — annual filing volume and IPC subclass share — show where activity has run and what kind of claim is being written.
Filings rose to a 2018 peak, then eased
Volume climbed to 7 filings in 2018, the high point of the window, then settled onto a lower plateau; the 2021-to-2024 comparison the dataset supports shows filings falling from 4 to 2, a 50% decline over that span. Because publication lag means 2025 and 2026 are still filling in, that fall should not be read as a definitive slowdown — only as the clearest complete-year comparison available.
Classification spreads across propulsion, measurement and power
B63H (marine propulsion and steering) accounts for 43.6% of the 211 records, confirming the hydrodynamic hardware is the dominant claim type. But G01R (electric and magnetic measurement, 19.4%) and H02J (power supply and grid systems, 17.5%) both post double-digit shares, and H04L (digital information transmission, 12.8%) is close behind — evidence that a meaningful slice of this field is instrumentation, monitoring and power-management filings adjacent to the mechanical device rather than the device itself.
Shares are the percentage of the 211 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Propeller Energy Saving Devices with Eureka
This page is one run against one query. Ask Eureka your own question about propeller energy saving devices and every answer comes back with the patent numbers behind it.
Try EurekaA representative filing and the most-cited prior art
Combined propeller cap for reducing rotational flow and hub vortex (EP3150482A1)
The filing addresses a specific manufacturing problem with the classic Propeller Boss Cap Fin: precise machining that makes it difficult and expensive to produce. Its solution couples a diffusion-type propeller cap to the end of a contraction-type propeller cap, reducing hub vortex cavitation generated behind the propeller, and adds guide fins to reduce it further.Filed by Korea Institute of Ocean Science and Technology, dated 2017-04-05.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20070228999A1 | Retrofit LED lamp for fluorescent fixtures without ballast | 464 |
| 2 | US7507001B2 | Retrofit LED lamp for fluorescent fixtures without ballast | 407 |
| 3 | US20120080949A1 | Power monitoring system | 52 |
| 4 | JP1988154494A | Propeller boss cap provided with fin | 40 |
| 5 | WO1999014113A1 | Propulsion system and method | 32 |
| 6 | EP0255136A1 | A screw propeller boss cap with fins | 29 |
| 7 | US20170363012A1 | Low-power bowed rotor prevention and monitoring system | 23 |
| 8 | US9106099B2 | Power monitoring system | 22 |
| 9 | WO2010139020A1 | Power monitoring system | 20 |
| 10 | US6678620B1 | Method for promoting energy saving in fluid machinery | 18 |
Citation counts favour older filings that have had more time to accumulate citations inside this corpus — read them as a signal of influence on the field's vocabulary, not as a ranking of current importance. The two highest-cited records here relate to LED retrofit lighting rather than propeller hardware, a reminder that citation weight in a mixed corpus can sit outside the core technology.
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Browse MCP servers →What the numbers mean for a filing decision
Three patterns stand out once the ranking, the trend and the classification split are read together.
A short list of repeat filers, then a long tail
The leading assignee alone accounts for 40 records against a fifth-place figure of 13 and a tenth-place figure of 8 — a steep drop-off. With the top ten holding 77.3% of all 211 records, most of the remaining 51 ranked companies hold only one or two filings each, typical of a field where a handful of specialist marine-engineering and research-institute filers set the pace.
Activity has eased from its 2018 high
Filing peaked at 7 records in 2018 and has not returned to that level since; the most recent complete comparison the dataset supports, 2021 to 2024, shows a 50% drop. Publication lag means 2025–2026 volumes will still rise as records are indexed, so this reads as a plateau after a mid-decade peak rather than a confirmed exit from the space.
Instrumentation and power systems are a real second axis
Beyond the 43.6% of records in core marine propulsion (B63H), sizeable shares sit in electric and magnetic measurement and in power supply and grid systems, with digital information transmission at 12.8%. That composition suggests condition-monitoring and power-management claims filed alongside or instead of pure blade-and-duct geometry.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to propeller energy saving devices, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| Mitsui O.S.K. Lines, Ltd. | Nishinippon Ryutai Giken Co., Ltd. | 10 |
| Mitsui O.S.K. Lines, Ltd. | MIKADO PROPELLER | 10 |
| Nishinippon Ryutai Giken Co., Ltd. | MIKADO PROPELLER | 10 |
| Mitsui O.S.K. Lines, Ltd. | Mitsui Engineering & Shipbuilding Akishima Research Institute | 8 |
| Mitsui O.S.K. Lines, Ltd. | Mitsui O.S.K. Techno-Trade, Ltd. | 8 |
| Mitsui Engineering & Shipbuilding Akishima Research Institute | Mitsui O.S.K. Techno-Trade, Ltd. | 8 |
| KRYLOV SHIPBUILDING RES INST | ABB Azipod Oy | 8 |
| Nagravision SA | BURCKARD ANTOINE | 1 |
The dataset records 10 co-assignee pairs, with three pairings each appearing 10 times among the same small cluster of research-institute and specialist propeller-fin filers — evidence of close, repeated collaboration rather than broad cross-industry co-filing.
The competitive set behind the ranking
Sixty-one companies appear in the assignee ranking for this scope — this is the complete list the data endpoint returns, not a top-50 or top-100 cut. Recent-year momentum for several of the more active names, including specialist propeller-fin research firms and a Korean ocean-science institute, shows zero filings in the latest year, consistent with the broader plateau seen in the trend data.
One assignee sets the pace by a wide margin
The top-ranked assignee's 40 records are roughly three times the fifth-place count of 13, marking it as the reference filer for anyone mapping prior art in this space.
A compact group of specialist filers
Between the leader and the long tail sits a small cluster of research institutes and propeller-hardware specialists, each holding single- or low-double-digit record counts — the group worth watching for freedom-to-operate checks even though none approaches the leader's volume.
Recent-year activity has gone quiet for known filers
Several assignees with meaningful historical filing counts, including a Korean ocean-science research institute and a Japanese fluid-dynamics research firm, show no filings in the latest year tracked — worth confirming against publication lag before reading it as an exit.
| Assignee | Recent year | YoY |
|---|---|---|
| Embertec Pty Ltd | 0 | — |
| Nagravision SA | 0 | — |
| Mitsui O.S.K. Lines, Ltd. | 0 | — |
| Korea Institute of Ocean Science and Technology | 0 | — |
| REDDING JOHN | 0 | — |
| Nishinippon Ryutai Giken Co., Ltd. | 0 | — |
| MIKADO PROPELLER | 0 | — |
| Mitsui Engineering & Shipbuilding Akishima Research Institute | 0 | — |
Where to take this analysis
The scope, ranking and trend above establish the shape of the field. Turning that into a filing or freedom-to-operate decision means going deeper on the specific claims and the specific gaps.
Check freedom-to-operate against the leader's portfolio
With one assignee holding 40 of 211 records, any new boss-cap or duct filing should be checked against that portfolio first, then against the fifth- and tenth-ranked filers before broader searching.
Run a claims comparison in EurekaPressure-test white space before drafting
The under-claimed sub-areas identified here — sensing integration, scale-correlation methodology, auxiliary power management — are starting points, not conclusions; each needs its own targeted search before a first claim is drafted.
Explore white space in EurekaCommon questions about propeller energy saving device patents
One assignee leads the ranked field with 40 of the 211 records in scope, well ahead of the fifth-ranked filer's 13 and the tenth-ranked filer's 8. The top five assignees combined hold 54.5% of all records, and the top ten hold 77.3%, so the field is concentrated among a small group of repeat filers even though 61 companies appear in the ranking overall. Anyone entering this space should check that leading portfolio first, since it is the most likely source of blocking prior art.
Filings peaked at 7 in 2018 and have not returned to that level since. The clearest complete-year comparison available, 2021 to 2024, shows a drop from 4 filings to 2 — a 50% decline over that span. Because publication typically lags filing by around 18 months, 2025 and 2026 figures are still incomplete and should not yet be read as confirming a continued slowdown.
A propeller boss cap fin (PBCF) is a fin structure fitted to the hub cap behind a propeller to reduce hub vortex cavitation and recover rotational energy lost in the wake, while a ducted propeller wraps a nozzle or duct around the propeller to change the flow field ahead of the blades. They solve the same efficiency problem through different mechanical routes, which is why the search scope for this landscape treats both as core device terms alongside the flow-physics language — wake field, hub vortex, cavitation risk — used to justify each design.
Beyond the 43.6% of the 211 records classified under B63H marine propulsion and steering, notable shares fall in electric and magnetic measurement (19.4%) and power supply and grid systems (17.5%), with digital information transmission at 12.8%. This spread indicates that a meaningful portion of filings in this scope cover monitoring, sensing and power-management systems built around the propeller hardware rather than the blade or duct geometry itself.
Relative to the dense core claim space around boss-cap and duct geometry, areas such as real-time cavitation-risk sensing integration, scale-correlation methodology for translating model-test results to full-scale hulls, and power-supply management for auxiliary duct thrusters show thinner filing density in this dataset. These are not guaranteed to be open — they need a dedicated search — but they sit at the edges of where the bulk of the 211 records concentrate.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.