Bring water, beer, OLD BAY and salt to boil in 12-quart stockpot on high heat. Add potatoes and onions. Cook 8 minutes. Add smoked sausage. Cook 5 minutes. Add corn. Cook 7 minutes.
Stir in shrimp. Cook 4 minutes or just until shrimp turn pink.
Drain cooking liquid. Pour contents of pot into large serving bowl or platter or mound on paper-covered table. Sprinkle with additional OLD BAY Seasoning if desired.