In a small bowl add the vinegar, oil, ketchup, soy sauce, Worcestershire sauce, rosemary, garlic, mustard and salt. Whisk to mix thoroughly and pour over meat. Cover and marinate for at least 1 hour or refrigerate overnight (best).
Stove Top: Remove meat from marinade. Add tablespoon of olive oil to a deep skillet or Dutch oven over high heat and sear meat on both sides. Pour marinade over and cover tightly with a lid. Bring just to a simmer on the stovetop over medium-high heat. Simmer on low for 2 hours. Add carrots, celery, onion and potatoes. Pour enough beef broth just to cover. Cook an additional 1 1/2 hours covered (2 hours for a 4 lb roast) or until the roast and potatoes are fork-tender. Remove meat to platter and carve. Skim fat from sauce and spoon over meat and vegetables.
Slow Cooker: Remove beef from marinade and reserve marinade. Add tablespoon of olive oil to a deep skillet or Dutch oven over high heat and sear meat on both sides. Spray inside of slow cooker with cooking spray. Add pan seared beef and reserved marinade, carrots, celery, onion and potatoes. Pour enough beef broth just to cover. Cook for 4 hours on High or 6 hours on Low. Remove meat to platter and carve. Skim fat from sauce and spoon over meat and vegetables.