What is the largest ship in the world?

The biggest ship in the world by gross tonnage is the crane vessel Pioneering Spirit at a staggering 403,342 GT. The ship was launched in 2013 and is used in the installation of oil platforms at sea. The largest ship in the world by length is the oil tanker Seawise Giant at 1,504 feet.

Does this ship has lounge or swimming pool?

There are no records to show if the ship has a pool or lounge. Though as the largest, assume that it has because even some cargo ships has a pool.