The present invention relates to a
moon pool and to a drillship comprising same. The
moon pool is formed in the drillship, and comprises a first space penetrating through an upper
deck from the bottom surface of the drillship to enable drilling, and a second space which is formed at the side portion of the first space in the lengthwise direction of the drillship, and which has a bottom surface opened toward the lower side of the drillship. As the second space of the
moon pool is formed at the side portion of the first space of the moon
pool in the lengthwise direction of the drillship, the moon
pool has an elongate
effective length, to thereby vary the vertical movement of the
seawater in the moon
pool and reduce resistance of the drillship during sailing. Further, a separation wall is arranged such that a top surface thereof is located at a predetermined height between the first space and the second space, to reduce the amplitude of sloshing movement of the
seawater in the moon pool, and reduce resistance caused by the sloshing movement. Further, the opening opened toward the lower side of the first space keeps the transverse width thereof at a constant level in the direction of the
stern of the drillship, and then is gradually tapered, thereby relatively reducing the amount of
seawater flowing into the first space and reducing resistance of the drillship.