In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.

서 론
재료 및 방법
결과 및 고찰
    A 지점에서의 투묘
    B 지점에서의 투묘
    C 지점에서의 투묘
결 론
사 사
References

• 김병엽(제주대학교 해양산업경찰학과 교수) | Byung-Yeob KIM (Professor, College of Ocean Sciences, Jeju National University, Jeju 63243, Korea)
• 김광일(제주대학교 해양산업경찰학과 교수) | Kwang-il KIM (Professor, College of Ocean Sciences, Jeju National University, Jeju 63243, Korea)
• 김민선(군산대학교 해양생산시스템전공 교수) | Min-son KIM (Professor, Marine Production System Major, Kunsan National University, Jeonbuk 54150, Korea)
• Kimura Nobuo(북해도대학교 수산학부 교수)
• 이창헌(제주대학교 해양산업경찰학과 교수) | Chang-Heon LEE (Professor, College of Ocean Sciences, Jeju National University, Jeju 63243, Korea) Corresponding author