Here is something that we have searched for for a very long time but have not found - complete fleet listings of the most famous shipping lines. If you want to see how long a certain ship served its company, here is the place to look.
   The ships names are the ones they had in the current shipping line's service, and the order in which the ships appear are consequent to the ship's maiden voyage - in the current shipping line's service or not. At the bottom of each document, you will find a listing of the company's ten largest ships.
 

French Line

White Star Line