Research On The Design Of T-Foil For Trimaran

Nowadays, with the continuous development of the vessels`type, the high-performanceships，like multi-hull vessels，with the unique appearance, excellent performance andmulti-tasking ability have aroused extensively interests in the industry of internationalshipping. Trimaran is a typical representative of the multi-hull vessels which owns manyadvantages, such as little resistance at a high speed and the spacious deck. Trimaran possessesexcellent seakeeping, especially it could avoid the phenomena of "twist shake" and "radicalshake" compared with catamaran. Trimaran can perform varied missions and meet thedemands of contemporary navigation, thus it attracts much attention around the world.However, due to its structural features, the bow of trimaran might be sunk down at a highspeed; as a result, its resistance would be increased. Meanwhile, in rough sea conditions, itstill has severe heave and pitch motions which would reduce the seakeeping performanceseriously. T-foil, as a device which can improve the ship’s seakeeping effectively, has beenwidely utilized internationally nowadays. In response to these issues, this paper will carry outthe research of T-foil to improve the seakeeping performance of Trimaran from three aspects：the method of T-foil design，the influence of installation location and the resistance influenceof T-foil. Eventually, this paper will form a complete design and analytical method of T-foilfor Trimaran.Firstly, based on the advanced panel method, the performance model of T-foil wasestablished. With the model, the preliminary design of T-foil is carried out, which includes thewing profile selection, shape design and pillar design. Then, the influences of free surface andhull to the hydrofoil were calculated and according to the results, the initial installation planswere determined. Secondly, this paper established the motions (heave and pitch) model oftrimaran, and based on the theory, the hydrodynamic coefficients in the equation were solvedtheoretically. With the model the antirolling effects in different installation location werecalculated. Then based on the ITTC double parameters spectrum, the antirolling effects inirregular wave were calculated, and the installation location was determined according to theresults. Finally, based on the Noblesse new slender-body theory, this paper established wavemaking resistance model of Trimaran, and the wave making resistance of target ship waspredicated. And the viscous drag of the ship was predicated with ITTC-57formula. Then，the total resistance of the ship with different length of pillar were calculated. According to theresults, the influence of T-foil was analysis and the length of pillar was determinedAccording to the results above, this paper form a complete method of T-foil design andanalysis for Trimaran and successfully designed a T-foil for the target trimaran and obtainsthe best installation scheme.