For sauce, melt butter in a 2 quart saucepan. Add ketchup, pineapple juice, brown sugar, onion, molasses, paprika and garlic powder. Boil for 5 minutes. Transfer to a large bowl and cover. Set aside.
Place ribs in a large stockpot. Cover with water. Bring to a boil. Reduce heat and simmer for 20 minutes or until cooked through and no longer pink.
While ribs are simmering, prepare a charcoal grill. When coals are hot, push them to one side of the grill.
Drain ribs. Using tongs, dunk ribs in sauce to coat. Place on grill. DO NOT PLACE THE MEAT DIRECTLY OVER THE HOT COALS. Cover grill and cook for 10 minutes. Using tongs, dunk each rib in sauce again and grill covered for an additional 10 minutes.