Developing methodology for model tests of floating platforms in low-depth towing tank

The paper presents two different methods of physical modeling of semi-submersible platform mooring system for research in low depth towing tank. The tested model was made in the scale of 1:100 resembling the “Thunder Horse” platform moored in the Gulf of Mexico at a depth of 1920 m. Its mooring system consisted of 16 semi-taut mooring lines (chain-wire-chain) spaced star-shape and attached at the bottom to suction piles. The tests were performed in the towing tank of the Gdansk University of Technology (GUT). The tank depth is 1.5 m and which is about 13.5 times less than that required for typical model tests. This required the development and use of non-standard methods of mooring for the model, which was adapted to the technical conditions existing in the laboratory and material possibilities. Numerical calculations and characteristics of static displacement of the model as a function of the external horizontal load were carried out for both anchoring systems. These characteristics were scaled to the natural conditions and compared with the calculated characteristics of the reference platform. The second method of modeling proved to be much more accurate.