An Objective Analysis of the 1956 Colllision Between Stockholm and Andrea Doria
Until now, a truly detailed and objective analysis of the collision between those two ships was never presented. Even though some works on this subject have started out that way, when all was said and done, they tend to take one side or the other and claim one ship was more to blame than the other. In my work on this subject, I was able to prove that the stories given by both sides in pretrial hearings that took place after the event simply do not hold up. It is not a question of one side being right and the other side being wrong. They both were inaccurate in what they claimed took place that night, including the details about distance and direction to the other vessel when visual contact was first established.
An interesting theory have been offered that the radar on the Stockholm was set on the wrong range scale. This was first put forth by John Carrothers in a paper he wrote back in 1971. It was picked up by Capt. Robert Meurn of the US Merchant Marine Academy as well as by the late David Bright. This theory, despite strong denials by the Stockholm's third officer, who was officer on watch at the time when the accident happened, also shows up in Pierette Domenica Simpson's relatively recent book, Alive on the Andrea Doria, and on the www.andreadoria.org website of the late Anthony Grillo. I tend to believe that such a misreading error was very unlikely. If the range was set to the 5 mile scale instead of the 15 mile scale, as the theory claims, the officer would not have failed to notice a closure speed that corresponded to something like 120 knots between ships. Something moving toward you at that high a relative speed is very hard to miss. Thus, in my opinion, there was no scale error. One look at the course recorder graph shows clearly why the bearings reported by the Stockholm’s helmsman at the time could not be reliable. Bad input data gives bad output data leading to wrong conclusions and bad decisions. Likewise, on the Andria Doria, those responsible never bothered to plot what was unfolding right in front of them,. They never had a clear picture of what was happening.
We do know what each party had claimed happened. From this I was able to create radar plots that not only show what was claimed to have been seen on their respective radars, but also such things as direction and distance to the closest point of approach predicted by the reported radar data, as well as the other ship's course heading calculated from radar vector triangles to compare against what was claimed. I was also able to analyze what was shown in the course recorder data of each ship, and work out the actual paths of both vessels relative to the collision point in a spreadsheet in 1/2 minute increments. In addition, the relative bearings and ranges of one vessel as seen from the other up until the collision itself was also worked out from the recorder data. I also was able to calculate the energies before and after impact, and the immediate movements of each ship from just moments before to moments just after impact which I was able to put into an animated sequence to recreate the collision itself. This is shown below.
Detailed Analysis Report