Trim the excess fat off of the short ribs with a knife and set aside.
Put a large 6 quart stock pot over a high flame add the water and short ribs and bring to a boil.
Skim any foam that floats to the surface with a spoon and discard. Once boiling add in the potatoes, carrots, onions, celery, potatoes, oil, salt and the bay leaves. Turn the flame down to medium and cook stirring occasionally until the meat is tender and begins to separate from the bone, about 1 hour and 30 minutes.
When the soup has about 20 minutes to go, bring pasta water to a boil. Break the spaghetti by hand into 2 inch pieces and drop them into salted boiling water. Cook until al dente.
Drain the pasta and add it to a bowl. Ladle the broth on top. Serve with lots of grated parmigiano reggiano cheese.