Ocean Nutrient Enhancer "TAKUMI" is a SPAR type floating structure with a riser pipe with a diameter of 1m, and a length of 175m. By pumping up the Deep Ocean Water containing rich nutrient salt, and sprinkling near the sea surface, plankton is made to increase and it aims at forming a good fishing ground. "TAKUMI" was installed in the Sagami Bay in May 2003 and is also working now. Previous to set up, two kinds of model tests were carried out in the deep-sea basin of a National Maritime Research Institute for the performance check. One is the enforced oscillation test of a riser model and the other is a test that investigates the response of the whole floating structure in regular waves, irregular waves and current. In this paper, the results of both tests are shown. With the frequency of oscillation, a riser pipe exercises at circular motion or for the form of the figure of 8. Although both results show good coincidence, the position of a node of the enforced oscillation test moves upper a little. About a hull motion and the occurrence frequency of strain, comparison between the result in the actual floating structure and model test was performed.
In generally, the upwelling and diffusing of Deep Ocean Water (DOW) that contain with nutrient salt can make the good fishing ground. Ocean Nutrient Enhancer "TAKUMI" is an artificially system of the upwelling and diffusing of DOW, and it was located at central of Sagami bay in May 2003. "TAKUMI" is a SPAR type floating structure with a riser pipe in its bottom side. A riser pipe is 175m in length and 1.0m in diameter. Mooring system is one line catenary mooring system consists of chain, wire and concrete sinker.
