Design and installation of ocean nutrient enhancer, 'TAKUMI'

Marino-Forum 21 (MF21, an incorporated association), installed a floating ocean nutrient enhancer, 'TAKUMI', 25 km off Hitratsuka City in Sagami Bay opening to the Pacific Ocean in a new attempt to develop a fishing ground in May 2003. The enhancer is an offshore structure which measures 213 m in height and 16.8 m in maximum width, and has a displacement of approximately 1,700 t. Construction was especially remarkable for towing a long and large structure in the sea, installing mooring cables in 1,000 m deep water, adopting an upending method to facilitate installation of a long riser pipe with a large diameter, This report describes the designing and installing procedures for 'TAKUMI', focusing on the three major points.