A Computational Analysis of the Capsize of the S/V Concordia

Open Access
Author:
Erdman, Matthew D
Area of Honors:
Mechanical Engineering (Behrend)
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • William Lasher, Thesis Supervisor
  • Amir Khalilollahi, Honors Advisor
Keywords:
  • Concordia
  • Heeling
  • Capsize
Abstract:
On February 17th, 2010, the Sail Training Yacht Concordia capsized off the coast of Brazil. The Transportation Safety Board (TSB) of Canada issued a Marine Investigation report (M10F0003) investigating the causes of the knockdown. One of the possibilities discussed was the occurrence of a downward component to the wind due to a microburst. In a draft of the report they concluded that there was insufficient evidence of a microburst to support that possibility, and suggested that the knockdown could be possible without the presence of a vertical component of wind. The captain of the Concordia at the time of the incident issued a response challenging this conclusion. In his response, the captain outlined supposed deficiencies in the report, insisting that the ship could not have capsized without a vertical component to the wind. The purpose of the present work was to investigate whether the Concordia could have capsized without a vertical wind component. It was initially hypothesized that the topsails, which were at an angle of attack to the horizontal wind and thus created a downward force similar to that of an airfoil, could have contributed to an additional heeling moment that caused knockdown. A CFD analysis showed that the sail force model used in the TSB report is inaccurate and the forces decreased with heel angle at a much faster rate than predicted. It is hypothesized that this was due to the hull “shielding” the sails from incoming wind, drastically decreasing the heeling moment as the heel angle approached 90°. It was concluded that the horizontal wind present in the squall was incapable of knocking down the ship, and thus at least some vertical component of the wind was present in the knockdown of the Concordia. It is recommended that agencies investigate the dangerous role that vertical wind can play in the capsize of sailing vessels.