On November 15, 2022, about 1835 Argentina time, the 413-foot-long passenger vessel World Explorer was anchored off Elephant Island, Antarctica, when one of the vessel’s zodiac small boats, carrying two guides and six passengers, capsized. The passengers and guides were washed ashore, where guides from other zodiacs provided medical attention. Two of the six passengers were pronounced dead at the scene (both US citizens).

The United States has been invited to participate in the investigation as a Substantially Interested State (SIS). When a flag State and/or investigating State designates the United States an SIS, the US Coast Guard represents the US Administration. ​​The NTSB may join the Coast Guard in their role as an SIS under the International Maritime Organization Code of International Standards and Recommended Practices for a Safety Investigation into a Marine Casualty or Marine Incident. 

​Under the International Maritime Organization’s (IMO) Casualty Investigation Code, the Office of Marine Safety participates with the US Coast Guard as a Substantially Interested State in investigations of serious marine casualties involving foreign-flagged vessels in international waters. For example, the NTSB often participates in investigations that involve foreign-flagged cruise ships with US citizens on board. Given the international nature of the marine industry and the number of foreign registered cruise and cargo ships operating from US ports, the investigation of casualties involving both domestic and foreign registered vessels promotes marine safety worldwide. The NTSB was invited to participate in the investigation as an SIS. We have produced an investigation close-out memorandum, which can be found in our docket.​