Easing of Under-Keel Clearance in Inland Waterway Transport

Prefectura Naval Argentina (PNA) is the Argentine Maritime Authority appointed by law; therefore, it is the relevant body entitled to enforce measures which guarantee navigation safety.

By virtue of Resolution 4/2018, PNA demands that vessels navigating Argentine rivers respect a minimum distance between the deepest point of the vessel and the bottom in still water, considering the height of tide at a specific place and moment. This minimum distance is called “Under-Keel Clearance (UKC)”.

According to the vessel’s draught and the area to be navigated, the required UKC may range from 60 cm or more to a 10 % of the maximum draught in the most difficult cases.

Instead of determining maximum draughts, the regulation includes in the UKC equation the height of tide so that the shipowner can use it as a reference and make optimal use of the vessel’s capacity, by loading it until it reaches the maximum draught which would allow the vessel to navigate safely and without risks of grounding.

The usual challenges are related to the chronology of cargo operations at cereal ports. Since the information of height of tide in the Río Paraná is updated once a day during the morning, the vessels finish loading the cargo hold with the values of the day when the operation starts, but at the moment of setting sail, the height of tide is different and the vessels are forced to change the UKC. If the UKC is lower than the one provided by the Resolution 4/2018, the vessel shall not be able to navigate and shall anchor until the height of tide increases.

For this reason and in view of minimizing or avoiding delays, Prefectura Naval Argentina issued directives (also approved by the Ministry of Transport) to ease the tolerance of UKC by allowing a decrease of up to 6 centimetres in case of unforeseen hydrological variations which would prevent the regulatory compliance.

Supplementary rules have been in force since November last year for the area from Timbúes to San Pedro, and then, in March, this area was extended to cover the navigation in the Río de la Plata.

This measure not only contributes with the optimization of the inland waterway transport, but it also reduces operating costs and improves the traffic flow in the river. Besides, it should be considered a supplementary rule for specific cases which does not contradict the limits of UKC provided by the Resolution 4/2018.