Aids to navigation are established to assist vessels in the navigation with special importance in narrow channels, rivers, or areas with special dangers to navigation. Whether the design of the aids to navigation (AtoN) system is optimum depends on ship positioning, which is affected by several factors: waterway geometry, metocean conditions, design ship, pilotage, and the AtoN themselves, being a crucial part of the design of a waterway.Optimizing the type of signals and the distance between them allows, not only for safer navigation, but to expand the limits of the waterway by assisting larger vessels to move safely along the waterway, as well as to minimize dredging costs and dredging area by optimizing simultaneously the design of both: the waterway and the Aids to Navigation. An equilibrium is required between the investment and maintenance costs, and therefore, this combined assessment and optimization allows to finally get both, technically and economically feasible projects without detriments on the safety of the waterway.The use of fast time manoeuvring models and Real Time Simulations allows to check and verify the optimization and improvements in the waterway and in the aids to navigation system. Real Time Simulators and manoeuvring sessions are the perfect place for all stakeholders (Port Authorities, Pilots, Harbour Masters, waterway designers, shipowners, …) to interact, discuss, evaluate, and agree on the best option for the improvement of navigation conditions while preserving the safety of the operations, as it allows to verify the effectiveness of the improvements before implementing them in the reality.

In inland ports, where access is done navigating along an estuary, river or artificial canal, the operation may be strongly conditioned by the tide (in case it has enough wide run) or the water level in the river. The variations in water level imply restrictions on the draft of the vessels that can access such ports.Siport21 has been working for several years in ports of these characteristics, where there is no possibility to dredge the inland waterway. The alternative is to develop synchronization analysis tools, which allow identifying the “operational windows” and maximizing the draft of the vessels in transit operations. The result takes advantage of the tidal run by means of adequate planning, so that there is always enough underkeel clearance safety margin.Grounding risk estimation is elaborated applying Monte Carlo method. A failure (grounding) function is defined, considering the propagation of the tidal wave (water level and current), ship speed along the waterway, wind conditions, squat, and other variables. Probability distributions of all variables involved are considered, so that thousands of random navigation conditions can be simulated. This allows to estimate the failure probability.This methodology is applied to a practical case of a port that is carrying out actions to improve and optimize its operations. To do this, AIS data and tide data along the entire waterway, obtained from measurement sensors and a calibrated numerical prediction model, have been used.