Improving the safety of passenger ships with the MARIN Ferry

Free running manoeuvring tests to evaluate the maximum heel angles when turning.

In 2018 MARIN participated in the investigation directed by the Sewol Investigation Commission on the sinking of the Korean ferry M/V Sewol. The ship capsized after experiencing extreme heel angles during a sharp turn and sank on 16 April, 2016 with 304 casualties. The results of this investigation highlighted the dramatic consequences of large heel angles and this accident triggered MARIN to raise awareness about this issue and to make sure that the international rules are adequate.

To this end, MARIN has conducted a series of dedicated model tests and calculations with an in-house model designed specifically to investigate this topic – a generic 190 m ferry called ‘MARIN Ferry’ whose hull lines are representative of contemporary ferries.

The first study was a free running manoeuvring test campaign, the main purpose of which was to evaluate the maximum heel angles when turning. Several important factors such as the length of the skeg, transverse stability and ship speed were varied. The heel angles were measured with pinpoint precision and quality checks indicated that the uncertainty of the heel measurements was very small. The results were compared to the current international rule concerning heeling in turn of passenger ships and it was concluded that this rule needed to be revised, because it systematically underpredicts the heel angles.

In a second test campaign, the MARIN Ferry was successively used in captive model tests, measuring hydrodynamic forces and moments in both upright and heeled conditions, for a wide range of drift angles and rotation rates. These tests provided insight into how the heel angles influence both the hull and steering forces, which enables improved modelling and the prediction of the heeling motions by means of manoeuvring simulations.

MARIN continues to research this topic, disseminating the knowledge gained and putting this subject forward within the IMO, with the ultimate goal of ensuring the required level of passenger safety.

Anton Kisjes | Victor Ferrari |