It has been argued that human and organizational factors are critical for accident analysis and safety management. The maritime domain represents a safety-critical system that has complex and temporary human collaborations. The level of collaboration includes not only human collaboration within a single ship, but also between ship-to-ship or ship-to-shore. From the safety-II perspective, these collaborations play a significant role in managing safety. Thus, this study suggests a framework to consider informal and temporary human collaborations using a functional resonance analysis method (FRAM) under the safety-II perspective. The framework is based on FRAM analysis and contributes by analyzing the level of human collaboration through establishing classifications of human collaborative relationships including the specified or unspecified relationships. Further, it supports organizing findings from the analysis and the derivation of strategy using templates and rules. The analyzed findings and derived strategy ultimately aim to help human's decision-making to adjust variable and uncertain situations by enhancing human collaboration. In particular, this framework is applied to maritime accidents analysis and safety strategy derivation. The authors believe that FRAM has the potential to be employed to other safety-critical systems and to be combined with safety analysis and management methodologies related to human collaboration.