TidesandCurrent
SASEBO
TIDES AND CURRENTS
The Mean High Water (MHW) interval at Sasebo Ko is 8 hours 21 minutes. Spring tides rise 9.5 ft (2.9 m) and neap tides rise 6.6 ft (2 m).
Currents within the Inner and Outer Harbors vary widely with the tidal flow. Those within 2 nmi of the Inner Harbor generally are less than 0.3 kt regardless of the stage of the tide.
The flood tidal current off Iorizaki (33° 07'N 129° 43'E) sets towards the head of the Harbor, and the ebb tidal current sets towards the entrance. The flow begins from 1 to 2 hours after HW or LW, and the rate does not exceed 0.5 kt. Off Kuchiki Zaki, a southeast current flows from 2 to 3 hours after LW, to 2 to 3 hours after HW, and a northwest current flows from 2 to 3 hours after HW, to 2 to 3 hours after LW. The rate of the southeast current seldom exceeds 0.5 kt, but the northwest current sometimes attains a rate of more than 1 kt.
At low tide, velocities approach 2 kt in the area 4 to 4.5 nmi south of the Inner Harbor (east of the main anchorage area near Ebisu Wan), and over 1 kt near the western entrance to the Outer Harbor. However, currents are generally not so strong as to hinder navigation. There is no record of a tsunami affecting the harbor.
A tidal gauge is located at Hizukushi-cho (33° 09.5)'N 129° 43.7'E) and is the property of the Japan Meteorological Agency.
Source: http://www.nrlmry.navy.mil/port_studies/thh-nc/japan/sasebo/text/sect6.htm
