Hutauruk, Ronald MangasiJamaluddinMurdijantoDJONI, I Made AryaUtama, Ikap2014-02-042014-02-042014-02-041412-2332wahyu sari yenihttps://repository.unri.ac.id/handle/123456789/5473Catamaran consists of two demihulls which are separated at certain distance. Both of demihulls induce interaction that generates viscous interference. Due to separation to length ratio between demihulls, interference effect occurs significantly over viscous resistance. These interference effects will be investigated by doing experimental test in the wind tunnel to analyze the pressure distribution and velocity profile on the catamaran. Catamaran model is designed without transition strip (turbulent stimulator). The models will be tested at various velocities, commenced from 10; 12; 14 dan 15.5 m/s in speed and separation to length ratio (S/L) 0.2, 0.3 and 0.4. Experimental results define that body separation effects both pressure distribution and velocity profile. Increasing of body separation will increase pressure distribution values. However, its increasing will decrease velocity profile values.enPressureflow velocitywind tunnelinterferenceUR-Scientific Work Lecturer