The submarine in the water is a murky gray in color, with a conning tower on top. It looks intimidating, yet sleek and glides through the water seamlessly. It is possible to imagine the submarine descending below the surface, searching for its quarry. To bring this scene to life, use a dark, deep blue for the water and a deep shade of navy to give the submarine a realistic feel. For added effect, the conning tower could be painted a pencil-shading gray to give it a sense of stealth. Incorporate air bubbles or waves for a seamless effect. Use lighter blues for the water surrounding the submarine for a subtle contrast. This will make the submarine stand out and give it an air of mystery as it descends further beneath the surface.