Pinpoint and Safe Installation of a Standalone Seafloor Observatory

Environmental impact assessment on the site of ocean resource exploration and exploitation is required to be conducted under regulatory guidelines to protect and preserve ecosystems and biodiversity. Thus, observatories that can achieve long-term monitoring are needed for such a purpose. In connection with this, we have developed a long-term ecosystem monitoring lander, called “LEMON lander,” and an equipment for its pinpoint and safe installation, called “pilot frame.” LEMON lander is attached at the pilot frame on deck and goes down to the seafloor by using an onboard winch. After the pilot frame landed on the seafloor, LEMON lander is released from the pilot frame. The falling distance from the pilot frame is less than 30cm and the safety during falling and landing is assured; moreover, the pilot frame is more than 330kgf in water and this allows to deploy at a target position even under a bit strong current. We have succeeded to deploy two LEMON landers by using the pilot frame for an actual mission. This paper focuses on the installation method using the pilot frame and reports the installation operation for the actual mission, together with brief introduction of LEMON lander.