Ship refit projects require ongoing plan management to adapt to arising work and disruptions. Planners must sequence work activities in the best order possible to complete the project in the shortest time or within a defined period while minimizing overtime costs. Activity scheduling must consider milestones, resource availability constraints, and precedence relations. We propose a constraint programming approach for detailed ship refit planning at two granularity levels, daily and hourly schedule. The problem was modeled using the cumulative global constraint, and the Solution-Based Phase Saving heuristic was used to speedup the search, thus achieving the industrialization goals. Based on the evaluation of seven realistic instances over three objectives, the heuristic strategy proved to be significantly faster to find better solutions than using a baseline search strategy. The method was integrated into Refit Optimizer, a cloud-based prototype solution that can import projects from Primavera P6 and optimize plans.