Offshore wind plays a crucial role in the green transition, with floating offshore wind (FOW) allowing access to deeper waters and expanding installation potential. However, further research is required to make FOW cost-competitive in these environments. This thesis addresses key challenges in mooring systems for FOW, utilizing the IEA 15 MW reference turbine on the UMaine VolturnUS semisubmersible platform [1] to match industry trends. The first chapter provides an overview of mooring systems and the research design process used throughout this thesis, including configurations, system components, modeling methodologies, design considerations, and evaluation methods. It also presents examples of mooring systems for existing FOW platforms. The second chapter investigates the impact of marine growth on mooring line behavior to inform structural health monitoring methods. Line tensions and positions are found to be sensitive to marine growth, with these sensitivities varying by mooring system type (catenary or taut) and environmental conditions. Dynamic simulations reveal variations in fairlead tension, node depths, and node velocities, suggesting a multi-parameter monitoring methodology tailored to each mooring system. Subsequent chapters focus on shared anchor systems. Chapter 4 characterizes cyclic loading for 3-line shared anchors, examining factors affecting cyclic capacity. Wave-driven cycles vary by site, providing insights for multiline anchor design. Chapter 5 compares modeling methodologies for farms with shared anchors, evaluating an uncoupled approach versus a coupled farm-level simulation tool. General agreement is observed between the methodologies, with differences noted due to wave coherence and wake effects. Chapter 6 compares 3-line and 6-line shared anchor layouts in deep waters, involving a comprehensive loads analysis, suction caisson design, and farm-level mooring cost assessment. While the 6-line system experiences higher loads, it exhibits lower inclinations and less variability, leading to similar suction caisson designs as the 3-line system. Shared anchor farms demonstrate cost reductions compared to baseline designs, with marginal differences between 3- and 6-line layouts. Wake modeling indicates varying impacts on anchor loads, with the baseline design showing the largest reductions in mean anchor loads due to wake effects.