A rescue mission off the coast of Lady Musgrave Island on the Great Barrier Reef in Queensland saved 46 people onboard a ship that caught fire and started sinking into the shark infested waters. The boat fire was caused by an explosion in the engine room around 4 p.m. on Wednesday.

The passengers of the 23 metre-long catamaran fled the sinking ship in life rafts. They are now being treated by paramedics, but there has been no case of serious injuries.

The smoke rising from the boat fire could be seen from the nearby town of 1770 as passengers, mostly Chinese tourists, and four crew members attempted to escape in life rafts at around 4:30 p.m. The ship was at a distance of 20 kilometres from the Musgrave Island on the Great Barrier Reef when it started sinking.

The Volunteer Marine Rescue and Gladstone Water Police arrived shortly after to conduct a rescue operation with the help of the local boat owners of 1770. The rescue operation lasted for more than five hours, with an Australian Maritime Safety Authority aircraft and helicopter offering an aerial view of the scene, News.com.au reported.

The Gladstone Observer reported that the onlookers described the fire as “very awful” and that it was the “the biggest thing they had ever seen.” The rescue crews, police boats, and helicopters could be seen from the shore.

Mail Online reported that it was not the first time that a Spirit of 1770 ended up in trouble. In January 2015, the boat smashed to the shore after being hit by a “freak wave.” The passengers were ferried back from Lady Musgrave Island.

Lady Musgrave Island is a popular tourist spot that allows a limited number of campers to stay on the island. There are also sightseeing cruises to the island. The island is the second in a trail of islands on the Great Barrier Reef.