Andrea Doria and Stockholm Collide

SS Andrea Doria was an ocean liner for the Italian Line home ported in Genoa, Italy, most famous for her sinking in 1956, when 52 people were killed (51 from immediate impact).

Named after the 16th-century Genoese admiral Andrea Doria, the ship had a gross register tonnage of 29,100 and a capacity of about 1,200 passengers and 500 crew. For a country attempting to rebuild its economy and reputation after World War II, Andrea Doria was an icon of Italian national pride. Of all Italy's ships at the time, Andrea Doria was the largest, fastest, and supposedly safest. Launched on June 16, 1951, the ship undertook its maiden voyage on January 14, 1953.

On July 25, 1956, while Andrea Doria was approaching the coast of Nantucket, Massachusetts, bound for New York City, the eastbound MS Stockholm of the Swedish American Line collided with it in what became one of history's most infamous maritime disasters. Struck in the side, the top-heavy Andrea Doria immediately started to list severely to starboard, which left half of its lifeboats unusable. The consequent shortage of lifeboats might have resulted in significant loss of life, but the efficiency of the ship's technical design allowed it to stay afloat for over 11 hours after the ramming.  The good behavior of the crew, improvements in communications, and the rapid response of other ships averted a disaster similar in scale to that of Titanic in 1912. While 1,660 passengers and crew were rescued and survived, 46 people died with the ship as a consequence of the collision. The evacuated luxury liner capsized and sank the following morning. This accident remains the worst maritime disaster to occur in United States waters since the sinking of the SS Eastland in 1915.

The incident and its aftermath were heavily covered by the news media. While the rescue efforts were both successful and commendable, the cause of the collision with Stockholm and the loss of Andrea Doria generated much interest in the media and many lawsuits. Largely because of an out-of-court settlement agreement between the two shipping companies during hearings immediately after the disaster, no determination of the cause(s) was ever formally published. Although greater blame appeared initially to fall on the Italian liner, more recent discoveries have indicated that a misreading of radar on the Swedish ship initiated the collision course, leading to errors on both ships. 

                                                    SS  Andrea Doria at home in Italy

While heavy fog would be the main reason given as the cause of the accident, and it is not disputed that intermittent and heavy fog are both frequent and challenging conditions for mariners in that part of the ocean, these other factors have been cited:

1. Andrea Doria 's officers had not followed proper radar procedures or used the plotting equipment available in the chartroom adjacent to the bridge of their ship to calculate the position and speed of the other (approaching) ship. Thus, they failed to realize the Stockholm 's size, speed, and course.
2. Andrea Doria had not followed the proper "rules of the road" in which a ship should turn to right (to starboard) in case of a possible head-on crossing at sea. As Stockholm turned right, Andrea Doria turned left (to port), closing the circle instead of opening it. Beyond a certain point, it became impossible to avoid a collision.
3. Captain Calamai of Andrea Doria was deliberately speeding in heavy fog, an admittedly common practice on passenger liners. The navigation rules required speed to be reduced during periods of limited visibility to a stopping distance within half the distance of visibility. As a practical matter, this would have meant reducing the speed of the ship to virtually zero in the dense fog.
4. Stockholm and Andrea Doria were experiencing different weather conditions immediately prior to the collision. The collision occurred in an area of the northern Atlantic Ocean off the coast of Massachusetts, where heavy and intermittent fog is common. Although Andrea Doria had been engulfed in the fog for several hours, Stockholm had only recently entered the bank and was still acclimating to atmospheric conditions. The officer in charge of Stockholm incorrectly assumed that his inability to see the other vessel was due to conditions other than fog, such as the other ship being a very small fishing vessel or a 'blacked-out' warship on maneuvers. He testified that he had no idea it was another passenger liner speeding through fog.
5. Andrea Doria 's fuel tanks were half empty and not pumped with seawater ballast to stabilize the ship, in accordance with the Italian Line's procedures. This contributed to the pronounced list following the collision, the inability of the crew to pump water into the port fuel tanks to right the ship, and the inability to use the port lifeboats for the evacuation.
6. Also, a watertight door may have been "missing" between bulkheads near the engine room, which was thought to have contributed to Andrea Doria’s problems.
7. The Stockholm 's navigating officer misread his radar thinking he was on a 15-mile setting when in reality the radar was set for 5 miles. Thus, he thought he was farther from the Andrea Doria than was so. He also failed to consult his captain as was required by regulation.

Both lines had an incentive to limit the public discussion of Andrea Doria's structural and stability problems. Stockholm 's owners had another new ship, the Gripsholm, under construction at Ansaldo Shipyard in Italy. Andrea Doria 's designers and engineers had been scheduled to testify, but the hearings were abruptly concluded before their testimony could be heard due to the settlement agreement.

https://en.wikipedia.org/wiki/SS_Andrea_Doria