Fill a large kettle no more than three-quarters full of seawater or salted water. Add 2 Tablespoons of salt for each quart of water. A good rule of thumb is to allow 2½ quarts of water for each lobster. Bring the water to a boil. Put in the live lobsters, one at a time, and let the water boil again. Lower the heat, cover the kettle, and simmer about 15 minutes for a 1- to 1¼-pound hard-shell lobster and 20 minutes for a 1½-pound hard-shell lobster. If the lobster has a soft shell, reduce the cooking time by 3 minutes.
Par-boil your lobsters in a large pot of boiling water for 5 minutes. Remove the lobsters and plunge into a large bowl of cold water to stop the cooking. Drain the lobsters and store in a refrigerator if you do not plan to grill them right away.
Place a lobster on its back on a cutting board. Using a large sharp knife split the lobster down the middle. Remove the black vein from the tail, the tomalley from the body and the sand sac located near the head. Repeat with the remaining lobsters. Baste the lobster meat with some oil or butter.
Grill the lobsters flesh side down for 5 to 6 minutes, or until the flesh is just beginning to look opaque. Turn the lobsters over, baste with more oil and continue to cook for 4 to 5 minutes longer, or until the lobsters are cooked through.
Instructions provided by Maine Lobster Promotion Council