Theoretical solution of impact force by VLCC moored to dolphins in irregular waves are obtained. Also observation are carried out at the presently operating berth. Computed values are comfirmed to agree with observed values.
　On the other hand, obsearved values are analyzed in order to obtain the relations between deflections of fenders and dolphins and the affection of wind and waves. And the followings are cleared.
(1) Deflection of mooring facilities by impact force of VLCC moored to dolphins are affected by waves than wind when wind velocity is less than 10 m/s. And even if wind velocity is in the range from 10～20 m/s, it does not affect so much when the wind direction is not laterally to ship's hull.
(2) Moored VLCC moves in the period coinsides to the natural period of the mooring systems.
(3) Histgrams of deflection of mooring facilities agree with Rayleigh's distribution. Relation between maximum values and significant valnes expressed as ymax=(1.5～1.6)y1/3.
(4) Virtual mass coefficient in sway motion of moored VLCC moored to dolphins are assumed as 1.7～2.0.