The interest in autonomous marine vessels has been continuously growing in the recent years. Most platforms of the autonomous surface watercraft involve traditional mono- or multi-hulls. Advanced marine vehicle concepts, such as hydrofoils, can provide high-speed and high seakeeping capabilities. In this study, a modeling effort is initiated for a small autonomous hydrofoil boat intended for intercepting operations. A 3-DOF model, including surge, sway and yaw, is applied for simulating maneuvering motions of the boat in the foilborne state. Forces generated by the propulsor, rudder and struts are accounted for in the simulations of the horizontal-plane boat dynamics. Two scenarios of a hydrofoil boat pursuing a moving target are investigated. In the pure pursuit, the interceptor always attempts to aim at the target and uses full thrust to quickly reach the target at a high speed. In the constant-bearing scenario, the interceptor approaches the target with diminishing speed trying to achieve a rendezvous. The presented models and results can help engineers to design more effective control methods for fast boats intended for intercepting operations.