Offshore wind energy can play a key role in the energy transition. Reducing installation costs for offshore wind installation projects helps to be cost-competitive with other renewable energy technologies. Installation costs can increase when the installation project planning is delayed. Literature shows that offshore wind installation projects are delayed by weather conditions exceeding operational limits and downtime caused by vessels and equipment. However, the magnitude and causes of downtime due to equipment breakdown are unclear. Additionally, no method is found in the literature to reduce downtime due to equipment breakdown in offshore wind installation. Data-analysis of observed failure data shows that equipment breakdown causes downtime during pinpile installation during the spring and summer seasons. Root-cause analysis indicates that scheduled preventive maintenance is often postponed on the critical path when weather conditions are favourable for installation. These decisions are made based on knowledge of oil and gas projects, but that knowledge is not applicable anymore. In this study a new method is proposed, which includes equipment characteristics and preventive maintenance on the critical path of an installation schedule, using discrete-event simulation (DES). In the DES model, four designs are simulated to gain insight into the effect of decision-making on the critical path on key performance indicators. The designs are based on the planned maintenance pillar of the Total Productive Maintenance framework. Implementing equipment breakdown and preventive maintenance in the installation schedule gives insight into the effects of decision-making before project execution. The results of this study indicate that the downtime due to breakdown and preventive maintenance of the hammer can be reduced by 10% if preventive maintenance is prioritized on the critical path.