In an emerging “blue economy,” the use of large multi-purpose floating platforms in the open ocean is being considered. Such platforms could possibly support a diversified range of commercial activities including energy generation, aquaculture, seabed mining, transport, tourism, and sea-based laboratories. A Markov decision process (MDP) framework is proposed to deal with operations and maintenance (O&M) issues that are inevitable; challenges arise from the complex stochastic weather conditions that need to be accounted for. Using data as well as contrasting synthetic simulations of relevant weather variables, we demonstrate the robustness/versatility of the MDP model. Two case studies—one involving constant and another involving time-dependent downtime costs—are conducted to demonstrate how the proposed MDP framework incorporates weather patterns from available data and can offer optimal policies for distinct metocean conditions (i.e., temporal variations in the weather). A realistic example that illustrates the implementation of the proposed framework for multiple O&M issues involving salmon net pens and wave energy converters demonstrates how our optimal policies can minimize O&M costs and maximize crew safety almost as if the true future were known for scheduling.