FILE - Duck boats sit idle in the parking lot of Ride the Ducks in Branson, Mo., July 21, 2018.
FILE - Duck boats sit idle in the parking lot of Ride the Ducks in Branson, Mo., July 21, 2018.

The Coast Guard on Monday raised the Ride the Ducks tour boat that sank on a Missouri lake last week, killing 17 passengers.

Cranes lifted the four-ton boat from 24 meters of water, drained it and lowered it onto a truck. Experts from the National Transportation Safety Board will investigate.

The Coast Guard said the probe will likely focus on whether the boat should have been operating in the first place with severe thunderstorms rolling in.

Winds close to hurricane strength may have caused the vessel to capsize and sink.

Witnesses said the weather was calm when the boat tour started. However, a Coast Guard official said investigators will want to know if operators were monitoring weather reports and knew a storm was approaching.

Thirty-one people were on the boat when it sank Thursday in Table Rock Lake near Branson, Missouri.

Seventeen people drowned, including nine members of the same family. One surviving member of the family said the boat's captain told passengers there was no need to put on life jackets. The captain was one of the survivors.

Duck boats were first used by the military in World War II. They have six wheels and can travel on both land and water.