Abstract: This study presents the design, development, scheme and field validation of an early-alert ocean wave system. It is designed to automate, improve, analyse, design and manage the daily construction activities of any harbour at construction stage. The objective is threefold: a) maximise construction safety, with regards to well-known hazards which occur during construction, especially breakwaters that interact with high-energy sea states, b) optimise the transport, by means of specialised vessels, of the refill material, and c) to minimise the construction delay and disruption on a daily basis, thanks to short-term construction forecasting (96 h). The system, known as PATO, offers short-term sea states characteristics, at any point near harbour structures, and relevant wave-structure interaction parameters at any harbour construction stage. The system is able to assist harbour project managers by providing accurate ocean wave data through a user-friendly interface.