Silversea Cruises has sliced their massive Silversea ship in half so that they can inset a 15 meter (50 feet) extension and increase the ship's capacity by 15 percent. While this kind of thing is commonly done to convert regular automobiles into stretch limos, the company describes this undertaking as a "rarely performed feat of maritime architecture." From CNN:
The elaborate engineering feat, underway at the Fincantieri Shipyard in Palermo, Italy, requires over 500 skilled workers and will take up approximately 450,000 man hours.
A prebuilt 15-meter extension (almost 50 feet) has already been inserted with "military precision" to stretch Silver Spirit from 195.8 to 210.7 meters.
(Thanks, Kelly Sparks!)