An underwater pelletizer is presented having an electromagnetic clamp that includes an electromagnetic ring body having a series of electromagnets disposed along a contact surface of the electromagnetic ring body. A clamping ring body has a series of mild steel inserts disposed along a contact surface of the clamping ring body, where each mild steel insert is disposed in a position complementary to at least one of the series of electromagnets. The electromagnetic clamp ring has a contact face with a series of electromagnets disposed therein and providing a clamping ring having a contact face with a series of mild steel inserts disposed therein, where the contact face of the clamping ring is configured to engage the contact face of the electromagnetic ring to form a seal and the mild steel inserts are positioned such that each one of the series of electromagnets is adjacent to one of the mild steel inserts when the contact faces of the electromagnetic and clamping rings are engaged. The method involves disposing the electromagnetic ring and the clamping ring between the water chamber and a die face, activating the series of electromagnets to clamp the electromagnetic ring to the clamping ring, and deactivating the series of electromagnets to gain access to the water chamber.