Combine the ketchup, vinegar, hot sauce, onion, garlic and Worcestershire
sauce in a mixing bowl and stir until blended. Pour half of the sauce into
a glass baking dish large enough to hold the ribs in a single layer. Place
the ribs meaty side down in the sauce. Pour remaining sauce over; cover and
refrigerate for 12 to 24 hours.

Heat a charcoal grill until the coals are thickly coated with ash. If you
are using a gas grill, preheat on low for 5 minutes with the lid closed.

Place the ribs on a rack set at least 6 inches from the fire. Grill
slowly, for 15 minutes. Turn and baste with sauce. Ribs should have
browned slightly. If they still look raw, stoke the fire. If they have
browned a great deal or scorched in spots, move ribs to a cooler part of
the fire. Cook for 15 minutes, baste, and turn again. Grill for 30 to 45
minutes longer, turning and basting, every 5 minutes. Watch the fire
carefully, keeping flames away from the ribs.

To serve, slice the rack into individual ribs and pile on a heated platter.

Serves 4.