Film Date: Master and Commander

I watched the film Master and Commander in Portsmouth (convenient location for a sea film) last weekend. Although fairly long, the film is packed with action and put together well, as if the viewer is a crew-member watching the story unfold. Cinematography is sensory and detailed and characterization is excellent. A good story and enjoying film. As it ended abruptly, I wonder if there is a sequel in the making. Why do many recent films seem to be made in preparation for a sequel?