Mainstay Marine Solutions

What Mainstay Marine Solutions does

Mainstay Marine Solutions Ltd is a specialist marine engineering and bespoke vessel builder operating from a 4.6-hectare deep-water site at the historic Pembroke Dock in South Wales, United Kingdom. The firm designs, fabricates, and delivers commercial vessels including pilot boats (16-22m), workboats, wind farm support vessels, patrol vessels, RIBs, floating bridges and chain ferries, alongside marine energy devices (wave and tidal energy converters) and defence components such as integrated communications masts for the Royal Navy's Type 26 City Class frigates and components for the Royal Australian Navy's Hunter Class programme. Operations are anchored by a 160t marine hoist, four slipways, a wet basin, ro-ro slipway, and 4000m² of covered workshop, supported by an in-house naval architecture team and a comprehensive welding, fabrication, mechanical/electrical engineering, and marine coatings capability. The firm is ISO 9001:2015, 14001:2015, and 45001:2018 certified, with 10% of the direct workforce maintained as apprentices to preserve skills continuity.

The business operates a project-based, contract-driven revenue model with bespoke vessels sold through direct sales, competitive tendering, and industry exhibitions (e.g., Seawork International). Customers span four primary verticals: offshore wind (Seacat Services, Turbine Transfers, Siemens Gamesa-adjacent operators), government maritime (Port of Milford Haven, Welsh Government, Environment Agency/Defra), defence (Royal Navy/STS Defence, Royal Australian Navy), and marine renewable energy developers (Bombora Wave Power, AMOG Consulting, QED Naval, Wave-tricity). Revenue streams include one-time vessel new builds, ongoing marine engineering/refit services, marine energy device fabrication, and defence component manufacturing. A 2024 partnership with Siemens Financial Services introduced a CTV financing channel with prices starting at £4.5 million per vessel.

Originally established as Mustang Marine (with operational heritage stretching back 40+ years), the company underwent ownership change in 2014, rebranded as Mainstay Marine Solutions in June 2015, and has since grown from 27 employees to over 80, with turnover rising from under £4m to over £5m by 2017. The trajectory has been reinforced by a new leadership team in early 2025, the RIBWORKER 2.0 product launch (June 2025), the Hunter Class Frigate contract (2025), and £1.2 million of matched OWGP funding (February 2026) earmarked to expand offshore wind manufacturing capacity.

Name

Mainstay Marine Solutions

Legal name

Mainstay Marine Solutions Ltd

Website

https://mainstaymarine.co.uk

Company type

Private

Founded year

2014

Operating status

Operating

Headcount range

11–50 employees

Ownership category

akta.pro rank

Product category

Marine vessel construction

NAICS

Ship Building and Repairing (336611), Ship and Boat Building (33661)

SIC

Ship & Boat Building & Repairing (3730)

akta.pro primary industry

Landing Craft & Amphibious Workboats (LCM/LCT-style, Beaching Craft) (IMAJADAK)

akta.pro secondary industries

Naval & Government Vessel Maintenance & Modernization (TLAKAKAB), Project Management & Owner’s Engineering / Technical Consultancy (Spec Writing, Bid Support, Site Support) (IMAJAGAO)

Keywords

• Marine vessel construction
• Workboat design and build
• Marine engineering services
• Offshore wind vessels
• Naval component fabrication

Headquarters

HQ city

South Wales

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Supply Chain, Infrastructure, Technology or R&D

Revenue model

1. Vessel New Build: Design, construction and delivery of bespoke commercial vessels including pilot boats, workboats, patrol vessels, crew transfer vessels, and passenger vessels. Revenue is generated through project-based contracts with delivery milestones.
2. Marine Engineering Services: Maintenance, repair, refit and servicing of vessels using facilities including slipways, wet basin, and 160t boat hoist. Provides ongoing revenue from existing vessel operators.
3. Marine Energy Device Fabrication: Fabrication and assembly of wave energy converters, tidal energy devices, and marine renewable energy infrastructure for developers and research institutions.
4. Component Manufacturing: Manufacturing and assembly of components for major programmes such as frigate masts and defence equipment, often through prime contractors.

Pricing tiers

Go-to-market motion2 records

Distribution channels2 records

Marketing channels4 records

Core offering

Mainstay Marine Solutions designs, builds and refits bespoke commercial vessels — including pilot boats, workboats, wind farm support vessels, patrol craft, RIBs, floating bridges and crew transfer vessels — from its deep-water Pembroke Dock shipyard. The company also fabricates marine renewable energy devices such as wave and tidal energy converters, and manufactures defence components (e.g. communications masts for the Royal Navy's Type 26 frigates and components for the Royal Australian Navy's Hunter Class frigates). Marine engineering services cover vessel maintenance, repair and refit using on-site slipways, a wet basin and a 160-tonne boat hoist.

Product overview

Mainstay Marine Solutions is a specialist marine engineering firm offering a comprehensive portfolio of vessel design, build, and fabrication services from their Pembroke Dock facility in South Wales. Their product portfolio centers on bespoke commercial craft including the RIBWORKER 2.0 aluminum RIB range, pilot boats (16m-22m), workboats, wind farm support vessels, patrol vessels, passenger vessels, and floating bridges/chain ferries. They have expanded into marine energy device fabrication, having completed multiple wave and tidal energy converter projects including Bombora's mWave, AMOG's WEC, and QED Naval's SubHub platform. The company also offers defense manufacturing capabilities producing components for programs like the Hunter Class Frigate and Type 26 frigate communications masts. In 2024-2025, they launched a UK-built Crew Transfer Vessel initiative in partnership with Siemens Financial Services. Their services encompass the full project lifecycle from in-house naval architecture and design through welding, fabrication, marine coatings, electrical/mechanical engineering, and project management.

Differentiator

Problem solved

Functional benefit

Brands

• RIBWORKER 2.0: Cutting-edge aluminium RIB range launched in June 2025, building on legacy of 1980s Ocean Dynamics RIBWORKER vessels. Fully compliant with Workboat Code 3 rulings, designed for defence, security, offshore patrol, search and rescue, and commercial applications.

Products and services

• RIBWORKER 2.0 Range A revamped aluminium RIB (Rigid Inflatable Boat) range engineered for performance over decades of demanding use. Fully compliant with Workboat Code 3 rulings and configurable for defence, patrol, search and rescue, USV support, salvage, dive support, crew transfer, scientific survey and commercial passenger applications. Customers include defence operators, search-and-rescue organisations and commercial passenger operators.
• UK-Built Crew Transfer Vessel (CTV) Initiative A pioneering UK-built Crew Transfer Vessel solution for offshore wind operators, offered in partnership with Siemens Financial Services for competitive marine finance. Cash price starts from £4.5m per vessel and the design is based on the Chartwell Ambitious Class compliant 25.2m aluminium catamaran with optimised hull form for fuel efficiency, stability and manoeuvrability in harsh conditions.
• Pilot Boats Expertly designed and built pilot boats ranging from 16m to 22m in length, delivered worldwide. Known for building quality vessels capable of withstanding exceptional weather conditions such as the three 19m pilot boats delivered to the Port of Milford Haven (rated for operation in heavy weather up to 5m swells).
• Workboats Commercially focused workboats delivered as bespoke vessels fit-for-purpose rather than off-the-shelf models. Covers multi-purpose vessels, tugs and dredgers, with experience spanning new builds and refits for commercial workboat operators.
• Wind Farm Support Vessels (WFSV) Specially designed vessels to serve the arduous demands of the offshore wind energy industry for transferring personnel, equipment, fuel or consumables. Delivered with focus on speed, durability and comfort to offshore wind operators including Seacat Services and Turbine Transfers.
• Patrol Vessels Robust patrol craft designed for territorial waters operations, available in varying national classifications including BV, MCA, DNV and Lloyd's Register. Includes fisheries patrol vessels for government customers and military/security craft. Customers include UK government fisheries protection and similar authorities.
• RIB (Rigid Inflatable Boats) Light-weight, high-performance and versatile aluminium RIBs available in multiple classes (C, D, E and O). Configurable for offshore/inshore patrol, search and rescue, or commercial passenger trips. The RIBWORKER 2.0 sub-range is fully Workboat Code 3 compliant and is positioned for defence, security, offshore patrol, SAR and commercial applications.
• Floating Bridge / Chain Ferry 37m Chain Ferry and Floating Bridge vessels for coastal transportation and harbour infrastructure applications. Designed for councils and harbour operators providing chain ferry services; can be tailored to site-specific operating conditions.
• Marine Energy Device Fabrication Specialised marine engineering services for marine energy device fabrication including design optimisation, welding and fabrication, mechanical and electrical engineering, marine coatings and blasting, drive train alignment, and project management. Customers include wave and tidal energy technology developers and research institutions (e.g. Bombora Wave Power Europe, AMOG Consulting, Wave-tricity, QED Naval).
• Marine Engineering Services (Maintenance, Repair, Refit) Vessel maintenance, repair and refit services delivered from the Pembroke Dock facility using its slipways, wet basin and 160-tonne boat hoist. Serves existing vessel operators across commercial, defence and offshore wind segments and provides ongoing service revenue.

Quantifiable outcome

• Delivered 20m wind farm support vessel on time and on budget with quality workmanship
• +2 more outcomes

Named customers14 records

Segments5 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature3 records

Partnerships

Seven partnerships are on record, tiered core and minor.

• Seacat ServicescoreStrategic or Co-development PartnerOngoing partnership to build offshore energy support vessels including Seacat's 20th vessel and fifth Chartwell Ambitious design. Seacat has invested more than £65 million in UK newbuilds over the last decade, with Mainstay as key UK shipbuilder.
• Bombora Wave Power EuropecoreStrategic or Co-development PartnerMainstay fabricated and assembled Bombora's 1.5MW mWave wave energy converting device. Bombora established European headquarters in Pembroke Dock in 2017 and awarded Mainstay its largest single contract for the device fabrication.
• AMOG ConsultingcoreStrategic or Co-development PartnerMainstay constructed AMOG's Wave Energy Converter (WEC) technology demonstrator device, deployed for testing at FaBTest. This was Mainstay's fourth marine energy fabrication project.
• QED NavalminorStrategic or Co-development PartnerMainstay undertook refit and fabrication works for QED Naval's SubHub platform for wave and tidal turbine support. QED Naval established operational base at Mainstay as part of long-term strategy to develop tidal farms in Wales.
• STS DefencecoreStrategic or Co-development PartnerMainstay awarded contract to build, fabricate and outfit integrated communications masts for Royal Navy's first three Type 26 City Class frigates over a five-year programme, representing national importance.
• Targe TowingminorChannel Partner/ Reseller/ DistributorMainstay delivered crew transfer vessel to Scottish tug operator Targe Towing for operations at BP's Hound Point Marine terminal. Targe Towing selected Mainstay over Turkish and Dutch yards for quality and health and safety standards.
• ORE CatapultminorStrategic or Co-development PartnerMainstay completed repairs and upgrades to test buoy for MEECE (Marine Energy Engineering Centre of Excellence) part of ORE Catapult, providing test and demonstration facilities within META (Marine Energy Test Area).

Scale indicators6 records

Recent moves7 records

Expansion highlights4 records

Direct peers

• Diverse Marine: Northern Ireland-based small workboat builder producing CTVs, wind farm support vessels, pilot boats and patrol craft directly competing with Mainstay in the UK and Ireland offshore wind and government markets.
• Manor Marine: UK-based boatbuilder in Poole producing fast offshore workboats, wind farm support vessels and pilot craft; comparable in size and customer base to Mainstay's workboat new-build line.
• South Boats Special Projects: UK fabricator of aluminium workboats, fast patrol craft and wind farm support vessels; structurally similar SME competitor to Mainstay in offshore wind and defence workboat segments.
• Strategic Marine (UK): Builder of aluminium workboats, CTVs and crew transfer vessels with a UK heritage (now Singapore-listed); competes head-to-head with Mainstay for wind farm support vessel orders, including bids for Seacat-class work.
• Wight Shipyard Co: Isle of Wight-based small shipyard building aluminium wind farm support vessels and passenger ferries; competes for similar UK and Channel Islands CTV and small ferry contracts as Mainstay.

Broad incumbents

• BAE Systems Maritime: Global defence shipbuilder whose Type 26 programme supplies the comms mast work Mainstay fabricates; indirect overlap as a prime contractor that both competes for and sources from smaller UK yards like Mainstay.
• Babcock International (Marine): Large UK defence and marine services group with shipbuilding, naval support and offshore capabilities; competes with Mainstay for naval architecture and engineering services and provides both overlap and infrastructure adjacency.
• Harland & Wolff: Belfast-based heavy shipbuilder with shiprepair and fabrication capabilities including offshore wind structures; a much larger UK incumbent that competes with Mainstay for Houlder-class fabrication work and defence orders.

Emerging players

• Chartwell Marine: UK-based offshore vessel design house whose Chartwell Ambitious CTV design Mainstay builds under licence; a strategic partner in Mainstay's CTV initiative and a partial-overlap peer in windfarm vessel design and consultancy.

Regional players

• Ferguson Shipbuilders: Publicly-owned Scottish shipyard at Port Glasgow building ferries and small commercial vessels; comparable scope in steel/aluminium workboat and ferry construction but primarily focused on Scottish government contracts.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/mainstay_marine
• Facebookfacebook.com/MainstayMarineSolutions
• LinkedInlinkedin.com/company/2315105

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles8 records

Funding overview

Funding rounds2 records

Investors2 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Mainstay Marine Solutions