Principal Mechanical Design Engineer

Location: Barrow-in-Furness. Enjoy the flexibility of hybrid and flexible working arrangements—let's discuss the options that work best for you!

Salary: Circa £55,000

As a Principal Mechanical Design Engineer, you will:

• Lead the end-to-end development of complex fluid systems, crafting designs that meet rigorous performance and environmental standards.
• Create and review high-value engineering deliverables, from schematics and P&IDs to calculations, system descriptions, and 3D models.
• Drive advanced system analyses , including flow, pressure, thermal, and transient modelling to validate performance under challenging conditions.
• Select and assess critical equipment (pumps, compressors, valves, heat exchangers, filters, tanks) to ensure they thrive in tough submarine environments.
• Champion technology integrity by reviewing supplier documentation, ensuring compliance with shock, vibration, atmosphere, temperature, maintainability, and access constraints.
• Influence design quality and safety through contributions to reviews, hazard studies, verification activities, and resolving technical issues.

Essential:

• Degree-level education, with Chartered Engineer status highly desirable.
• A solid background in mechanical, marine, process, or fluid systems engineering within a complex or highly regulated environment.
• Strong knowledge of fluid dynamics, thermodynamics, pressure-drop behaviour, transient analysis, and system performance modelling.
• Demonstrated technical expertise in the design, analysis, and integration of both compressible and incompressible fluid systems.

Desirable:

• Experience with industry-standard modelling and analysis tools such as FloMASTER, FluidFlow, MATLAB, CFD packages, ANSYS, or similar.

We offer a competitive pension scheme, employee share plans, and a wide range of flexible, discounted health, wellbeing, and lifestyle benefits. This includes a green car scheme, private health plans, and shopping discounts. You may also be eligible for an annual incentive!

This is an exciting opportunity to join the SSN AUKUS Platform Mechanical Integrated Delivery Team as a Principal Mechanical Design Engineer. You’ll be a technical specialist for some of the submarine’s most critical fluid systems. In this role, you’ll take ownership of high-integrity mechanical designs that must perform flawlessly in one of the most demanding engineering environments. You’ll shape complex system solutions, influence platform-level decisions, and ensure designs meet the rigorous performance, safety, and environmental requirements unique to submarine engineering. This is your chance to work at the forefront of next-generation naval capability, tackling challenging technical problems and contributing directly to one of the UK’s most advanced defence programmes. Relocation support is available for eligible candidates across all Submarine roles.

At BAE Systems, you’ll make a real difference in an inclusive culture that values diversity of thought and rewards integrity and merit. We empower you to fulfill your potential and welcome people from all backgrounds. If you have a disability or health condition that may affect your performance in certain assessments, please discuss potential reasonable adjustments with your recruiter.

Important Note: Many roles at BAE Systems are subject to security and export control restrictions. Factors such as nationality, previous nationalities, and place of birth may affect your eligibility for certain roles. All applicants must meet the Baseline Personnel Security Standard, with many roles requiring higher levels of National Security Vetting, typically necessitating 5 to 10 years of continuous residency in the UK.

Closing Date: 19th December 2025

We reserve the right to close this vacancy early if we receive sufficient applications. If you’re interested, please submit your application as soon as possible!

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