Job Title: Principal Mechanical Engineer Location: Barrow-in-Furness. We offer a range of hybrid and flexible working arrangements - please speak to your recruiter about the options for this particular role. Salary: Circa £55k What you''ll be doing: Design of multiple platform systems, sub-systems and equipment for the next generation Royal Navy submarines Undertake functional design activities, modelling and analysis Produce design documentation, Verification and Validation evidence and safety justifications Support specification qualification and procurement of components, working collaboratively with suppliers Engaging with stakeholders across the cross-functional project team Driving engineering governance through peer reviews and design reviews Your skills and experiences: Essential: Proven capability in system lifecycle delivery - from concept through to commissioning Demonstrated leadership - either through technical direction, mentoring, or project ownership Degree Level Qualification or Chartered engineer or working towards professional accreditation. Mechanical Engineering background in Rotator Machinery, Components or Fluid Dynamics. Desirable: Knowledge of platform-level constraints such as noise, shock, or survivability Previous experience integrating purification systems with submarine life-support, HVAC, and emergency protocols Experience in the design of gas scrubbing, filtration, and environmental control systems (e.g. CO removal, O generation, trace