Annular anchor installing instrument and annular anchor installing method

An annular anchor installing instrument configured to cooperatively install an annular anchor (1) opened at its upper and lower ends, comprising

• an installation tube (2), one end of which is provided with a cover body (3), and an other end of which is configured to be an open end for cooperating with the top of the annular anchor (1);
• a pump body assembly (4) arranged on said cover body (3), and used to vacuum the interior of said installation tube (2);
• a lifting portion(S) arranged on said cover body (3), and used to connect with a hoist;
• and
• installation portions (6) which are removably arranged on said cover body (3), and used to connect with the hoist and the anchor chain (7) of the annular anchor (1), respectively, so that the annular anchor (1) is coaxially fixed to the open end of said installation tube (2) by connecting with the anchor chain (7) of the annular anchor (1);
• wherein the hoist includes a first hoist (14) and a second hoist (15), the lifting portion(S) on the cover body (3) is connected with the first hoist (14), and the lifting plate (12) of the installation portion (6) is connected with the second hoist (15);
• after the installation portions (6) is detached from the cover body (3) by a underwater robot, the second hoist (15) places the installation portion (6) and the anchor chain (7) onto a surface of surrounding seabed.