Since 2008 Babcock Canada has provided complete lifecycle engineering support for Canada’s fleet of Victoria-Class submarines. This includes platform design, integration, configuration, management services, and maintenance and waterfront support. Babcock Canada is currently completing an Extended Docking Work Period (EDWP) on HMCS Victoria where extensive surveys, repairs and upgrades will be undertaken across the entire platform. During the survey of the submarines aft end structure, encompassing ballast tanks and free flood spaces, extensive wastage was identified across the shell plating. Given the scope of shell plate repairs required and the alignment sensitivity of the propulsion and maneuvering operating gear and shafting this engineering work was classified as “high-risk professional activities or work” under Engineers and Geo-scientists British Columbia (EGBC) guidelines. Babcock Canada undertook Finite Element Analysis (FEA) to mitigate technical risk and provide significant schedule savings with the sequencing of the repair and to help identify the maximum extent of shell plate removals technically required at each stage of the repair.  Furthermore, the projects tactical operational planning approach, focused on a streamlined execution methodology in collaboration with key stakeholders, in order to deliver the desired outcome for this highly technical phase of work. Part of this was carrying out an extensive risk analysis with mitigation strategies implemented, dynamic scheduling and change/configuration control. This presentation will demonstrate the survey and technical sentencing process, repair options considered, the engineering governance associated with high-risk professional activities or work and how the complex technical risk was balanced against the enterprise cost and schedule objectives to achieve success.