BEIJING, Dec. 30 -- A six-month investigation into a cruise ship disaster on the Yangtze River in June, killing 442 people, has uncovered problems in the shipping company's daily management and local regulators' supervision.

Although the State Council investigation team concluded that heavy storms caused the Eastern Star to capsize, it also found management issues in the running of the shipping company and local authorities, and suggested that 43 people be punished accordingly.

The Eastern Star, with 403 tourists, 46 crew members and five travel agency staff aboard, was on an 11-day trip along the Yangtze River when it capsized on June 1. Only 12 people survived.

The incident was "an extraordinarily serious disaster" caused by strong winds and heavy rain resulting from a squall line accompanied by a downburst, according to the official report.

The owner of the Eastern Star, Chongqing Eastern Shipping Corp., had taken the liberty to modify the ballast tanks without requesting an official inspection afterward, according to the official report.

The firm also failed to give proper training to its crew on how to respond to inclement weather conditions, the report said.

The investigation team said Captain Zhang Shunwen and his chief mates had "insufficient knowledge" about extreme weather and possible dangers, and had "responded inadequately."

The report proposed that the captain's certification be revoked and that the judiciary decide whether he had committed a crime.

Other flaws by the firm included insufficient checks on cabin facilities and lax monitoring over the ship's condition.

Local authorities, including ports and maritime safety administrations, have been accused of inadequate ship examination and lax water transport permit issuance, according to the report.