Authorised Cummins Marine Engine and Onan Generator Specialists
Engineering-led installation, service, parts supply and long term support for commercial and leisure vessels.
Authorised Mercury Marine Platinum Dealer
Outboard supply, installation, servicing, engineering and parts support.
Cummins Power Generation Sales & Support
Authorised Halyard Dealer
Marine and industrial exhaust, sound insulation and onboard system supply, installation and support.
About
Southampton-based Marine, power generation and Industrial engineering
Vasi Southern Ltd is a Southampton-based engineering company providing specialist support across marine propulsion, industrial systems, and engine-driven power generation.
The business is built on decades of hands-on experience within the marine and power sectors, delivering integrated mechanical, electrical, and electronic solutions for engines, generators, and associated equipment. Alongside engineering services, we provide specialist parts supply and technical support, forming a core part of our day-to-day operations.
Our team brings over two decades of specialist experience supporting leading engine and power generation manufacturers, combining practical engineering knowledge with deep, system-level parts expertise.
Parts are supplied as a technical service, not a transaction — ensuring correct identification, specification, and compatibility first time. We operate as an authorized and approved partner for leading manufacturers, allowing us to supply parts, equipment, and complete systems in accordance with manufacturer standards and best practice, while helping clients avoid unnecessary downtime, repeat intervention, and long-term reliability issues.
Sectors
Commercial Marine
Engineering support for working vessels and commercial operators.
Propulsion, onboard power, generators, and technical systems where reliability and uptime are critical.
Industrial & Power Generation
Industrial & Power Generation
Engine-driven power system support for industrial and commercial applications.
Generators, control systems, and technical support delivered with an engineering-led approach.
Superyacht
Discreet, manufacturer-approved engineering support for professionally managed yachts.
Engines, generators, onboard systems, and technical support delivered to exacting standards.
Leisure Marine
Trusted engineering and technical support for private and owner-operated vessels.
Outboard and inboard propulsion, generators, servicing, and specialist parts supply.
Our Approach
Engineering-led decision making
Every job starts with correct diagnosis and specification. We prioritise reliability, compliance, and long-term performance over short-term fixes or unnecessary replacement.
Parts supplied as a technical service
Parts supply is treated as a critical engineering function. Correct identification, compatibility checking, and manufacturer-aligned selection help prevent downtime, repeat visits, and costly errors.
Manufacturer-aligned standards
Where authorised, we work to OEM procedures and best practice. Where alternative brands or systems are assessed, work is undertaken on a case-by-case basis with the same technical discipline.
Clear communication and accountability
We provide realistic scopes, clear advice and expectations — with support that continues beyond installation, service, or repair.
Services
Marine
Inboard and outboard propulsion support, including engine supply, installation, servicing, fault diagnosis, and long-term technical support for commercial and leisure vessels.
→ Marine Propulsion
Generators and industrial systems
Marine and industrial generator systems, including Onan and Cummins-based installations, servicing, maintenance, and technical support for engine-driven power applications.
→ Generators & Power Systems
Service, maintenance & overhaul
Planned maintenance, fault diagnosis, corrective repair, and major overhaul work delivered with an engineering-led, right-first-time approach.
→ Service, Maintenance & Overhaul
Electrical & electronic integration
Integration and support of onboard electrical and electronic systems, including controls, monitoring, charging systems, and associated power management equipment.
→ Electrical & Electronic Integration
Parts & Technical Support
Specialist parts supply backed by deep technical knowledge. Correct identification, specification, and manufacturer-aligned support for Cummins, Mercury, Halyard, and associated systems.
→ Parts & Technical Support
Main Dealer Southampton UK
Authorised
Authorised
Authorised
Authorised
Testimonials
Proudly Rated 5 Stars
They supplied, configured and installed new Cummins engines to my faithful Princess 435. As thoe old engines were Volvos this required a great deal of primary engineering and exhaust design. They were meticulous and professional throughout and the results have been a spectacular success. Not only an excellent result but such a great ream to work with. Strongly recommend!
Andrew Gay
