Marine Propulsion Patents: Top Companies & Filing Trends 2026
- Filing has flattened, not grown. activity peaked at 11 families in 2018 and the 2022 midpoint sits at 5, with no sustained recovery through the most recent full year.
- Claim density concentrates in one subclass. 362 of 376 families sit in B63H (marine propulsion & steering), meaning almost every filer is competing inside the same core classification rather than spreading across adjacent engine or hull subclasses.
- The most-cited prior art is decades old. the top-cited record, a multi-speed shifting mechanism, dates to a 1997 grant — a sign that foundational propulsion mechanics were settled early and recent filings build narrowly on top of it.
What this landscape covers
This dataset tracks patent families filed or published against marine propulsion systems, drawing on titles and claims referencing marine propulsion, ship propulsion systems and podded propulsors, cross-checked against abstract and claim text mentioning cavitation, propeller efficiency, dual-fuel engines, shaft generators and emission compliance. The IPC scope is anchored on B63H5 (propulsion units for water-borne vessels), B63H21 (transmission gearing for marine propulsion) and F02B43 (dual-fuel and gas-fuelled internal combustion engines), which keeps the corpus focused on propulsion hardware rather than general shipbuilding.
376 families span 2015 through mid-2026, filed across receiving offices led by the United States, the European Patent Office and Japan. Because publication trails filing by roughly 18 months, the final year or two of this window will fill in further as pending applications publish — the flat-to-declining trend described here should be read as a lower bound on true recent activity.
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Filing trend and technology composition
Two views of the same 376-family corpus: how filing volume has moved year over year, and how those families distribute across the IPC subclasses that define the propulsion stack.
A peak in 2018, then a plateau
Annual filings ran from 1 family in 2017 up to a peak of 11 in 2018, then settled toward a midpoint of 5 by 2022. The most recent full year shows no return to peak levels, consistent with a mature core claim space rather than an expanding one.
One dominant subclass, several thin satellites
B63H (marine propulsion & steering) accounts for 362 of 376 records, dwarfing F02B internal-combustion engines (66), B63J ship auxiliaries (42), B63B vessels (36), and smaller counts in F02D engine control, F02M fuel supply, F01N exhaust treatment and F01K steam plant. The gap between B63H and everything else shows most inventive effort goes into the propulsion unit itself rather than the surrounding power or exhaust systems.
Shares are the percentage of the 376 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Marine Propulsion Systems with Eureka
This page is one run against one query. Ask Eureka your own question about marine propulsion systems and every answer comes back with the patent numbers behind it.
Try EurekaKey patents shaping the field
Marine propulsion trim tab with anti-ventilation means
The representative record discloses a lower-unit assembly combining an anti-cavitation plate, a trim tab extending aft of the propeller, and a deflector that pressurizes water ahead of the trim tab during forward travel. The construction targets ventilation and cavitation control at the propeller rather than engine or fuel-system changes.Filed by Outboard Marine Corporation, granted 1976 — illustrates how early the mechanical cavitation-control approach was staked out.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5711742A | Multi-speed marine propulsion system with automatic shifting mechanism | 90 |
| 2 | US5009621A | Torque splitting drive train mechanism for a dual counterrotating propeller marine drive system | 75 |
| 3 | US5632658A | Tractor podded propulsor for surface ships | 62 |
| 4 | US6363875B1 | Method and apparatus for trimming a dual electric motor marine propulsion system | 56 |
| 5 | US5746270A | Heat exchanger for marine engine cooling system | 54 |
| 6 | US6146223A | Marine propulsion unit with water inlets in all quadrants of the front portion of its torpedo-shape gearcase | 52 |
| 7 | US6527603B1 | Fuel delivery system for a marine propulsion device | 49 |
| 8 | US3793980A | Marine propulsion system | 47 |
| 9 | US4871334A | Marine propulsion device with improved exhaust discharge | 46 |
| 10 | US5967866A | Texture gearcase for a marine propulsion system | 43 |
Citation counts reflect influence within this searched corpus and skew toward older, foundational filings — they are not a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Reading the filing trend, IPC split and citation pattern together points to a field where the core mechanical problem was solved early and recent activity is incremental.
Growth has not resumed since the 2018 peak
Annual filings climbed from a single family in 2017 to 11 in 2018, then eased back toward a midpoint of 5 by 2022. Absent a rebound in the still-publishing recent years, this reads as a plateaued rather than expanding field.
Almost every filer competes in the same subclass
B63H marine propulsion & steering covers 96% of the corpus, far outweighing F02B engines, B63J auxiliaries and the remaining subclasses combined. New entrants are filing into an already crowded core rather than opening adjacent ground.
Foundational mechanics were claimed decades ago
The most-cited record in the corpus, a multi-speed shifting mechanism, and the next several most-cited records on counter-rotating drive trains and podded propulsors, all originate from the 1990s. Recent filings build narrowly around this base rather than replacing it.
Named leaders show no latest-year filings
Every assignee tracked for recent-year momentum, including a major volvo-affiliated filer down 100% year-on-year, shows zero filings in the latest year of the dataset. Some of this reflects publication lag, but it also signals reduced near-term appetite from the historical leaders.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to marine propulsion systems, with the prior art for and against each one.
Who holds the ground, and where it is thin
Ownership in this corpus is anchored by outboard-engine and marine-drive specialists with long filing histories; the co-assignee data shows most collaboration is between a single hull-and-engine pairing rather than a broad partner network.
One partnership dominates joint filing
Of 10 identified co-assignee pairs, the strongest links a hull builder with an engine and drivetrain partner across 9 shared families — far ahead of any other pairing in the dataset, most of which show only 2 shared filings.
US filings lead, but Europe and Japan are close behind
The United States receives more filings than any other office (137), with the EPO (49), Japan (42), WIPO/PCT (30), the UK (27) and Canada (22) forming a secondary tier. This spread suggests protection strategies that prioritise the US market first and add PCT or regional coverage selectively.
Historical leaders have gone quiet in the latest year
Assignees with long filing histories in outboard engines and marine drives, including major Japanese and European names, all show zero filings in the latest tracked year. Whether this reflects a genuine pull-back or simply publication lag will only be clear once the current filing year finishes publishing.
| Assignee | Recent year | YoY |
|---|---|---|
| Outboard Marine Corporation | 0 | — |
| Brunswick Corporation | 0 | — |
| Mitsubishi Heavy Industries, Ltd. | 0 | — |
| Yamaha Motor Co., Ltd. | 0 | — |
| Volvo Penta | 0 | -100% |
| Fuel Saver Ltd. | 0 | — |
| E P BARRUS | 0 | — |
| Siemens AG | 0 | — |
Where to take this analysis
The dataset points to a mechanically mature core and several thinner adjacent subclasses. The next steps depend on whether the goal is freedom-to-operate, white-space filing, or tracking a specific competitor.
Map claims against the B63H core
Before filing anything touching propeller or podded-propulsor mechanics, check claim scope against the dense B63H cluster and the decades-old most-cited records that still anchor it.
Explore claim charts in EurekaTest the under-claimed branches
Shaft generator integration, exhaust after-treatment and waste-heat recovery show materially lower filing density than the propulsion core and may offer more open claim space.
Run a white space search in EurekaWatch for republished activity
Zero latest-year filings across tracked leaders may partly reflect the 18-month publication lag rather than a real slowdown; recheck this cohort as later years fill in.
Set up assignee monitoring in EurekaCommon questions on marine propulsion patents
The corpus is led by a small group of long-established outboard-engine and marine-drive manufacturers, alongside major shipbuilding and heavy-industry firms. Ownership is concentrated rather than fragmented across many equal-sized filers, and several of these leading assignees show no filings in the latest tracked year, which may reflect either reduced activity or publication lag on recent applications. Anyone doing freedom-to-operate work should check the full assignee ranking rather than relying on name recognition alone, since some smaller filers hold individually influential patents.
Almost all records in this dataset touch B63H, the IPC subclass for marine propulsion and steering units, with much smaller but still meaningful activity in internal-combustion engines (F02B), ship auxiliaries (B63J), vessel hulls (B63B), and engine control, fuel supply, exhaust treatment and steam plant subclasses. This means the bulk of inventive activity is in the propulsion unit itself — propellers, pods, drivetrains — rather than in the surrounding engine or emissions systems. Filers targeting dual-fuel or emission-compliance angles are working in a comparatively thinner part of the landscape.
Filing activity peaked at 11 families in 2018 and had eased to a midpoint of 5 by 2022, with no clear return to peak levels in the years since. Because patent publication typically lags filing by about 18 months, the most recent one to two years in this dataset will look artificially low until pending applications catch up. Even accounting for that lag, the multi-year pattern points to a plateaued field rather than one in active expansion.
US3955527A claims a specific mechanical combination: an anti-cavitation plate, a trim tab extending aft of the propeller from that plate, and a deflector positioned to pressurize water ahead of the trim tab during forward travel. It does not block cavitation-control approaches that use different structural arrangements, such as electronic control of propeller pitch or blade-geometry changes rather than a trailing trim tab and deflector assembly. Anyone designing a lower-unit cavitation solution should map their structure against this specific claim combination rather than assuming all trim-tab designs are covered.
Relative to the dense B63H propulsion core, subclasses tied to exhaust after-treatment for emission compliance, steam and thermal waste-heat recovery, and shaft generator integration with dual-fuel engines show materially fewer filings. These areas sit adjacent to well-established propulsion claims but are not yet crowded, which typically means less prior art to design around when drafting a first claim. Confirming this requires a targeted search within each subclass rather than relying on the aggregate counts alone, since a handful of strong patents can still dominate a thin area.
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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.