Trim fat from roast. If necessary, cut roast to fit into crock pot. In a skillet brown roast on all sides in hot oil. In a bowl combine tomato juice, vinegar, worcestershire sauce, sugar, salt, basil, thyme, pepper, and garlic. In 6 qt. crockpot, place carrots and onion. Sprinkle tapioca over vegetables. Place roast atop vegetables. Pour tomato mixture over roast. Cover; cook on low-heat setting for 10-12 hours or high-heat for 5-6 hours. Transfer meat and vegetables to a platter. Skim fat from gravy. Serve gravy with mashed potatoes.