Duramax Marine
Duramax Marine LLC manufactures water-lubricated marine bearings, heat exchangers, shaft seals, and impact protection systems for military, commercial, and recreational vessels. Its proprietary Johnson Cutless and ROMOR I bearings are installed on over 90% of U.S. Navy surface ships and submarines.
- Company typePrivate
- Founded1999
- HeadquartersHiram, United States
- Headcount51–100
- GTM typeB2B
- OfferingHardware or Manufacturing
What Duramax Marine does
Duramax Marine LLC is a privately held manufacturer of marine propulsion and vessel protection equipment headquartered in Hiram, Ohio. The company designs and produces water-lubricated bearings, heat exchange systems, shaft seals, and impact protection products for military, commercial, and recreational marine markets. Its flagship Johnson Cutless bearing is the original water-lubricated rubber bearing in the industry, and the company holds proprietary material formulations spanning nitrile rubber compounds, polymer alloys (DMX), composite materials (DuraBlue), and UHMW-PE composites. Duramax products are installed on more than 90% of U.S. Navy surface ships and submarines and are certified by ABS, Lloyd's Register, RINA, DNV, Bureau Veritas, and Vietnam Maritime Administration, with bearings meeting MIL-DTL-17901C Class II specifications.
The company operates an engineering-led, quote-based business model selling custom-engineered hardware through a combination of direct phone sales staffed by product experts, a global network of stocking distributors, and regional warehouses in Ohio and Louisiana. It maintains in-house R&D capabilities including an 800,000-gallon testing facility built in 1998 for full-scale keel cooler evaluation, an accredited laboratory, and CFD-validated product development workflows. Customers include the U.S. Navy, U.S. Coast Guard, allied navies worldwide, and commercial operators such as Maritime Partners LLC with its approximately 2,000-vessel towboat and barge fleet, as well as recreational boat owners purchasing through local distributors. In November 2024, Duramax expanded its product portfolio through an asset acquisition of Morse Rubber LLC's marine bearing, dock fender, and marine bumper business from FLSmidth Group.
Duramax sells through five core product lines: Johnson Cutless rubber sleeve and flange bearings, Advanced Bearings (ROMOR I stave, DMX Polymer Alloy, Demountable Stave, and DuraBlue Composite), DuraCooler heat exchange systems (including the patent-pending SuprStak double-stacked configuration), Shaft Seal Systems (DryMax, stuffing boxes, mechanical face seals, Ultra-X packing), and Impact Protection Systems (EPDM dock bumpers, tow knees, Linerite batterboard). The company holds 10 registered trademarks, maintains ISO 9001:2015 certification audited by Smithers Quality Assessments, and competes on the basis of proprietary materials science, regulatory certifications, and an installed base that supports long-tail service revenue including bearing relining.
Duramax Marine firmographics
Firmographics- Name
- Duramax Marine
- Legal name
- Duramax Marine LLC
- Website
- https://duramaxmarine.com
- Company type
- Private
- Founded year
- 1999
- Operating status
- Operating
- Headcount range
- 51–100 employees
- Short description
- Duramax Marine LLC manufactures water-lubricated marine bearings, heat exchangers, shaft seals, and impact protection systems for military, commercial, and recreational vessels. Its proprietary Johnson Cutless and ROMOR I bearings are installed on over 90% of U.S. Navy surface ships and submarines.
- Ownership category
- akta.pro rank
Duramax Marine industry classification
Industry- Product category
- Marine Bearings & Vessel Propulsion Components
- NAICS
- Ship Building and Repairing (336611), Synthetic Rubber Manufacturing (325212)
- SIC
- Ball & Roller Bearings (3562), Plastic Materials, Synth Resins & Nonvulcan Elastomers (2821), Miscellaneous Plastics Products (3080)
- akta.pro primary industry
- Sealants, Adhesives, Gaskets & Marine Elastomers (IMAJAKAL)
- akta.pro secondary industry
- Deck Fittings & Hardware (Bitts, Fairleads, Cleats, Anchors & Chains) (IMAJAIAK)
Keywords
Where Duramax Marine is headquartered
LocationHeadquarters
- HQ city
- Hiram
- HQ country
- United States
- HQ region
- North America
Offices3 records
Markets served
Duramax Marine business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Supply Chain, Operations, Personnel, Technology or R&D, Marketing or Sales
Revenue model
- Marine Bearing Systems: Water-lubricated bearing systems including Johnson Cutless, ROMOR I, DMX, and DuraBlue products. Revenue from sleeve bearings, flange bearings, stave bearings, rudder bushings, thrust washers, shaft sleeves, and stern tube fillers. Custom engineered to customer specifications.
- Heat Exchange Systems: Custom engineered cooling systems including DuraCooler keel coolers, SuprStak double-stacked coolers, Demountable spiral tube coolers, and BoxCooler systems. Quote-based custom design for vessel-specific cooling requirements.
- Shaft Seal Systems: DryMax shaft seals, Johnson Heavy-Duty stuffing boxes, Ultra-X compression packing, and mechanical face seals. Hardware products with various size configurations.
- Impact Protection Systems: Commercial dock bumpers, fenders, tow knees, pusher plates, and Linerite composite batterboard systems. EPDM rubber products with various profile configurations.
Go-to-market motion2 records
Distribution channels3 records
Marketing channels7 records
Duramax Marine product offering
Product offeringCore offering
Duramax Marine manufactures and sells proprietary water-lubricated marine bearings (Johnson Cutless rubber bearings, ROMOR I stave bearings, DMX polymer alloy, DuraBlue composite stern tube bearings), DuraCooler heat exchange systems (keel coolers with SuprStak variants, demountable spiral tube coolers, BoxCoolers), shaft seal systems (DryMax, stuffing boxes, mechanical face seals, Ultra-X packing), and impact protection systems (EPDM dock bumpers, fenders, tow knees, Linerite batterboard). Products are sold through an international distributor network and direct sales to military, commercial, and recreational marine customers, with custom engineering offered for heat exchangers and bearing systems.
Product overview
Duramax Marine is a manufacturer of marine propulsion and vessel protection products organized into five core product lines: (1) Water-Lubricated Bearings including Johnson Cutless rubber bearings (the original true cutlass bearing) and Advanced Bearing Systems (ROMOR I stave bearings in dovetail and radius-back configurations, DMX Polymer Alloy bearings, Johnson Demountable Stave bearings, and DuraBlue Composite stern tube bearings and rudder bushings); (2) Heat Exchange Systems including DuraCooler keel coolers (with SuprStak double-stacked patent-pending variant), Demountable spiral tube coolers, and BoxCooler in-hull systems; (3) Shaft Seal Systems including DryMax axial shaft seals, Johnson Heavy-Duty Air Seal stuffing boxes, mechanical face seals, and Ultra-X compression packing; (4) Impact Protection including EPDM dock bumpers/fenders in multiple series, tow knees/pusher plates, and Linerite composite batterboard; and (5) Industrial products for hydro power and vertical pump applications. The company also offers NCB shaft sleeves and stern tube filler as accessories. Founded over 100 years ago, Duramax Marine serves military, commercial, and recreational marine markets worldwide with ISO 9001:2015 certification.
Differentiator
Problem solved
Functional benefit
Brands
- Johnson Cutless: Water-lubricated rubber bearings and sleeve bearings product line; the original and only true Cutless bearing brand; used in more vessels worldwide than any other water-lubricated bearing.
- DuraBlue
- DuraCooler
- DryMax
- Ultra-X
- DMX
- ROMOR I
- Linerite
Products and services
- Johnson Cutless Water-Lubricated Bearings The original true cutlass bearing, using proprietary nitrile rubber polymer bonded into naval brass or non-metallic shells. Available as sleeve bearings and flanged bearings in shaft sizes from 3/4" to 6-1/2" for strut and stern tube applications. First and only bearing to meet all MIL-DTL-17901C Class II requirements. Used in more vessels worldwide than any other water-lubricated bearing; serves military, commercial, and recreational marine markets.
- Advanced Water-Lubricated Bearing Systems Custom-engineered high-performance water-lubricated bearing solutions including ROMOR I stave bearings (dovetail and radius-back configurations) with nitrile rubber bonded to UHMW-PE backing, DMX polymer alloy stave bearings for abrasive environments, Johnson Demountable Stave bearings allowing replacement without shaft or propeller removal, and DuraBlue composite stern tube bearings and rudder bushings. ABS, Lloyd's, RINA, DNV, and Bureau Veritas approved for various configurations.
- DuraCooler Heat Exchange Systems Custom-engineered marine heat exchange systems including the DuraCooler keel cooler (improves heat transfer more than 17% over traditional designs), DuraCooler SuprStak double-stacked keel cooler with TurboTunnel design that more than doubles heat transfer in half the hull space (patent pending), 90/10 cupronickel Demountable spiral tube keel coolers in 4 to 24 tube configurations, and Duramax BoxCooler in-hull cooling systems with Impressed Current Anti-Fouling (ICAF). Custom quote-based design for vessel-specific cooling requirements.
- Shaft Seal Systems Complete line of marine sealing systems including the DryMax water-lubricated axial shaft seal (uses no grease or oil; features DuraChrome mating ring and inflatable air seal for at-sea maintenance; ABS type approved), Johnson Heavy-Duty Air Seal stuffing boxes (bronze construction, repacking at sea without dry-docking, shaft sizes 2.5" to 36"), Duramax Mechanical Face Seal System (maintenance-free for shafts 3/4" to 6-3/4" in BRZ/FRP/Weld-On configurations), and Ultra-X high-performance PTFE compression packing (outlasts flax 5 to 1, 300% lower friction).
- Impact Protection Systems Commercial-grade impact protection for vessels and dock structures including EPDM rubber dock bumpers and fenders (ASTM D2000 specification, available in 100-2100 series profiles), rubber-to-metal bonded tow knees/pusher plates (single, double, pre-curved, and segmented models with steel or aluminum substrates), and Linerite composite batterboard systems combining thermoset elastomer/plastic with UHMW-PE facing as a replacement for wooden timbers. EPDM products can last 4X longer than SBR or butyl fenders per company claims.
- NCB Shaft Sleeves and Johnson Cutless Stern Tube Filler Accessories supporting bearing installations and stern tube maintenance: NCB Shaft Sleeves with Nickel-Chrome-Boron alloy hard coating (58-62 Rockwell C hardness, extending shaft and bearing wear life by 4-5 times) and Johnson Cutless Stern Tube Filler (environmentally-friendly water displacement medium for freeze damage protection during winter layup, available in 5-gallon size).
- Duramax Industrial Products (Hydro Power and Vertical Pump Bearings) Industrial extension of Duramax water-lubricated bearing technology serving hydro power generation and vertical pump applications, applying the same proprietary rubber and composite bearing technologies used in marine propulsion to non-marine industrial rotating equipment.
Quantifiable outcome
- More than 90% of U.S. Navy surface ships and submarines operate with Duramax water-lubricated bearing technology
- +9 more outcomes
Companies that use Duramax Marine
Customer profileNamed customers4 records
Segments3 records
Ideal customer profiles3 records
Duramax Marine technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature6 records
Duramax Marine partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- Morse Rubber LLC (FLSmidth Group)coreDuramax Marine acquired the assets related to the marine bearing, dock fender, and marine bumper business from Morse Rubber, a member of the FLSmidth Group of companies. The transaction includes tooling, inventory, and equipment related to the marine business, moving to Duramax Marine facilities in Ohio. Neither facilities nor employees were included in the transaction.
Scale indicators6 records
Recent moves5 records
Expansion highlights6 records
Duramax Marine competitors and assessment
Company assessmentDirect peers
- John Crane: Smiths Group division specializing in mechanical seals, shaft seals, and bearing systems for marine, oil & gas, and process industries. Closely comparable to Duramax's DryMax water-lubricated shaft seal and mechanical face seal product family.
- Thordon Bearings: Canadian manufacturer of water-lubricated propeller shaft bearings and stern tube bearings for marine and industrial markets. Direct head-to-head competitor to Duramax's Johnson Cutless, ROMOR, and DuraBlue product lines, serving the same commercial marine and naval newbuild/retrofit customers.
- GGB Bearing Technology: Manufacturer of polymer, composite, and self-lubricating plain bearings used in marine, hydropower, and industrial applications. Direct material-and-application overlap with Duramax's DMX polymer alloy, DuraBlue composite, and DuraChrome technologies.
- Trelleborg Marine & Infrastructure: Division of Trelleborg AB producing marine fenders, dock bumpers, and vessel impact-protection systems. Directly comparable to Duramax's EPDM dock bumpers, tow knees, and Linerite batterboard portfolio following the 2024 Morse Rubber asset acquisition.
- Miko Marine: Norway-based specialist in marine fenders, foam fenders, and vessel docking protection systems. Comparable to Duramax's impact protection business in product scope and customer base (shipyards, ports, towboat operators).
Broad incumbents
- SKF: Global rolling-element and plain bearing manufacturer serving marine, industrial, and aerospace end markets. Comparable in bearing category breadth to Duramax's water-lubricated bearings but at vastly greater scale and without Duramax's water-lubricated depth.
- GEA Group: German manufacturer of heat exchangers, separators, and marine process equipment. Comparable to Duramax's heat exchange systems business within a much larger industrial portfolio.
- Wärtsilä: Finnish broad marine systems integrator providing ship power, propulsion, and lifecycle services. Operates overlapping equipment (seals, bearings, heat exchangers) inside a much wider portfolio that includes engines and integrated solutions.
- Alfa Laval: Swedish manufacturer of marine heat exchangers, separators, and fluid handling equipment. Direct overlap with Duramax's DuraCooler keel cooler and heat exchange product line as part of a broader marine equipment portfolio.
- Trelleborg Sealing Solutions: Trelleborg division producing precision polymer and elastomer rotary seals, O-rings, and custom-molded elastomer components. Comparable to Duramax's shaft seal and Ultra-X compression packing product family in elastomer sealing science.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks5 records
Key highlights6 records
Customer concentration
Duramax Marine social profiles
Digital presenceDuramax Marine compliance and trust
Trust signalCompliance21 records
Duramax Marine financial estimates
Financial estimateRevenue estimate
Valuation estimate
Duramax Marine leadership team
Management profileNumber of profiles
Profiles1 record
Duramax Marine funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Duramax Marine M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Duramax Marine
What does Duramax Marine do?
Duramax Marine manufactures and sells proprietary water-lubricated marine bearings (Johnson Cutless rubber bearings, ROMOR I stave bearings, DMX polymer alloy, DuraBlue composite stern tube bearings), DuraCooler heat exchange systems (keel coolers with SuprStak variants, demountable spiral tube coolers, BoxCoolers), shaft seal systems (DryMax, stuffing boxes, mechanical face seals, Ultra-X packing), and impact protection systems (EPDM dock bumpers, fenders, tow knees, Linerite batterboard). Products are sold through an international distributor network and direct sales to military, commercial, and recreational marine customers, with custom engineering offered for heat exchangers and bearing systems.
Is Duramax Marine a public or private company?
Duramax Marine is a private company. It is classified as unknown and is currently operating.
When was Duramax Marine founded?
Duramax Marine was founded in 1999. It employs 51 to 100 people.
Where is Duramax Marine based?
Duramax Marine is headquartered in Hiram, United States, in the North America region.
How does Duramax Marine make money?
Four revenue lines are on record. Marine Bearing Systems are the primary driver. The others are heat Exchange Systems, shaft Seal Systems and impact Protection Systems.
Who are Duramax Marine's main competitors?
Direct peers on record are John Crane, Thordon Bearings, GGB Bearing Technology, Trelleborg Marine & Infrastructure and Miko Marine. Broad incumbents are SKF, GEA Group, Wärtsilä, Alfa Laval and Trelleborg Sealing Solutions.
Does Duramax Marine have an API?
No public API is recorded for Duramax Marine.
What industry is Duramax Marine in?
Duramax Marine's product category is Marine Bearings & Vessel Propulsion Components. Its primary akta.pro industry code is IMAJAKAL, Sealants, Adhesives, Gaskets & Marine Elastomers, with a secondary code of IMAJAIAK, Deck Fittings & Hardware (Bitts, Fairleads, Cleats, Anchors & Chains). Its NAICS code is 336611 and its SIC code is 3562.