Finding HMAS Sydney Chapter 6 - Selection and Integration of Constraints
HMAS Sydney II: P2 4-inch gun at aft end of gun deck port side. Copyright: Australian War Memorial. Selection and Integration of Source Arguments 6
The first set of figures depict a simple form of triangulation Assume that three observers are near the coast at Cape Cuvier, Cape Inscription and the Zuitdorp Cliffs. Assume that each one of the observers saw a column of flame at 2400 on November 19 th , 1941, and that they each took a bearing on that column. Assume that the three bearings were 235° (from Cape Cuvier), 272 ° from Cape Inscription and 290° from the Zuytdorp Cliffs. The figure depicts the three bearings. The bearings produce a triangle or so-called “cocked hat” around the location of the flame. The obvious assumption is that the explosion was from inside or near to the triangle. The general procedure has been in use for nearly 400 years. Triangulation: An illustration
The figures includes the so-called “cocked hat” and one of the three bearings, from Cape Cuvier www.aboutaustralia.com / .../cape-cuvier-coast/ Bearing of Flame from Cape Cuvier: 235°
The figures includes the triangle and one of the three bearings, from Cape Inscription. Bearing of flame from Cape Inscription: 272° www.lighthouse.net.au/lights/WA/Cape%20Inscri
The figures includes the triangle or “cocked hat”and the third of the three bearings, from Zuitdorp Cliffs Bearing of Flame from Zuitdorp Cliffs: 295° www.sharkbay.org/default.aspx?WebPageID=134
Bearing of Flame from Zuitdorp Cliffs: 295° Bearing of Flame from Cape Inscription: 295° Bearing of Flame from Cape Cuvier: 235° Success: Source is from inside the “cocked hat”
This section describes the procedure actually used by Kirsner and Dunn (2004) to define the location of Kormoran. The procedure unfolded in two stages. Stage 1 involved selection of nine constraints based on cognitive and other criteria. Stage 2 involved a form of nautical triangulation involving mathematical integration to define Confidence Contours for the position of the wreck of Kormoran The central position in the Confidence Contour Map was 26° 04’ South 111° 02’ East, just 2.7 nautical miles from the position of the wreck of Kormoran (Kirsner & Dunn, 2004, Finding Sydney Foundation, 2005, 2007). Selection of Constraints
Each disc reflects one report Constraint 1: 26° South or 111° East: 18 Reports that referred to 26° South and 111° East. These reports were mostly from crew in a position to know. The category also included a number singletons that referred to 26° South or 111° East. These were rejected The first constraint involves a specific position
Constraint 2 Two reports that one life-boat sailed ≈ 150 nm NE from Kormoran to a known position on the coast The second constraint involves a specific position; the point of origin for the two lifeboats
Constraint 3 Three reports that referred to 120 nm from land were included but 3 other reports involving 150 nm and 60 nm from the land were discarded The third constraint involved a contour, reflecting distance from the coast
Constraint 4 One report that battle occurred “160 nm SW of NW Cape” was accepted although Cape Cuvier was substituted for NW Cape The fourth constraint involved a specific position
Constraint 5 Reports that battle occurred “130 nm South-West of Shark Bay” The fifth constraint involved a position
Constraint 6 The majority of the Interrogation reports from Detmers referred to 26°34’ S 111° E, 26° 32’S 111° E, 26° 31’ S 111° E as the position of the battle The sixth constraint involved a specific position
Constraint 7 Report that QQ signal from Kormoran referred to ≈ 26° S 111° 15 E Longitude was included in the analysis, and alternative latitudes were tested to determine the best fit with the balance of the sources. The seventh constraint involved a line of longitude
Constraint 8 Report by Detmers that Kormoran would (have been) off Shark Bay four hours after contact with Sydney (from estimated position of Kormoran at 1600) The eighth constraint involved a position, and an assumption about Kormoran’s movement after that
Constraint 9 Circle of Equal Distance for two life-rafts reported by Dunn and Kirsner (2001) The analysis was originally implemented to test the claims advanced by Warren Whittaker, Glenys McDonald, David McDonald and others - that the action took place off the Abrolhos Islands. The analysis was mathematical and involved no assumptions about wind or current. Given equal velocity for 84 and 107 hours for two life-rafts, the circle defined the range of positions from which the two liferafts could could have originated. The circle passed within 1.5 nm of the wreck of Kormoran The ninth constraint involved a circle.
The summary figure constituted overwhelming evidence that Kormoran was near 26° South 111° East. The only other option involved the assumption adopted by Whittaker, and assume that all of the Germans were lying.
<ul><li>Assumptions </li></ul><ul><li>Critical information was distributed among the crew for survival reasons. We assumed therefore that the most accurate analysis would reflect the opinions of a number of sources, the crucial assumption being that they held reliable information for reasons of survival </li></ul><ul><li>Many of the individual reports were incorrect or ambiguous, but the errors tended to cancel each other out, as one would expect with a large database </li></ul><ul><li>Mearns </li></ul><ul><li>Mearns was provided with the above analyses and recommendations during 2004 – 2005. Mearns rejected the arguments specific to Kirsner and Dunn (2004) and the Finding Sydney Foundation (2005) </li></ul><ul><li>Mearns did not produce a search box that included Kormoran until 2008,ignored the search definition work by the Finding Sydney Foundation in his book, and claimed that his history of the search was the “whole” history of the history of the search (see dust jacket) </li></ul>
<ul><li>Comment </li></ul><ul><li>The approach outlined above does not have any obvious precedents in the wreck-hunting literature. Importantly, it worked. </li></ul><ul><li>The model included seven constraints that involved cognitive analysis. One relied on Signal Information received on the coast. The ninth involved a mathematical model concerning the movement of the lifeboats recovered by Aquitania and Trocas. </li></ul><ul><li>The extent to which our approach would generalize to wreck-hunts that include information less dependent on cognitive analysis is unclear. </li></ul>
NSK Kormoran: Stbd concealed underwater torpedo tube. Copyright: Australian War Memorial. Integration of constraints based on Human Judgement (Kirsner & Dunn, 1998)
Context Between 1993 and 2005, the search agenda was dominated by map dowsing, navigation and oral history claims, and the searches implemented by the RAN , the RAAF and private companies concentrated near the Abrolhos Islands, 200 nm from the wrecks. Prior to 2005, three groups supported a search in the vicinity of the wrecks, near 26° South 111° East; the HMAS Sydney Foundation Trust between 1996 and 2001; the Finding Sydney Foundation (2001-2010) , and Olson, Hore, Goldsmith and Vickridge (2001).
Kirsner & Dunn (1998) was submitted by the Ed Punchard-led HMAS Sydney Foundation Trust to the Parliamentary Inquiry in 1998. According to Kirsner and Dunn (1998), “Kormoran sank a few miles to the north of 26 ° 15’ South 111° East”. Assuming that “few” means 3-5, the magnitude of the error was 7-10 nm.
Kirsner and Dunn (1998) Kirsner and Dunn (1998) Predicted Position given as, “ Kormoran sank a few miles to the north of “ 26 °15’ South 111° East. Error = Distance between Predicted and Observed positions ≈ 7 - 10 nm FSF / Mearns (2008) Observed position of Kormoran
NSK Kormoran: Stbd concealed underwater torpedo tube Mearns’ decision to omit reference to the fact that the Finding Sydney Foundation provided him with the precise positions of both wrecks, accurate and efficient search boxes for each wreck, and a powerful and scientific rationale for their work has not been explained. The authors put the question to HarperCollins in 2009.
Kirsner (1997) Example of ‘integration’ or ‘triangulation’
HMAS Sydney II: Starboard UK1 12-foot rangefinder Barbette for Director Control Tower. Copyright: Australian War Memorial. Integration based on Mathematical Decision Model (Kirsner and Dunn, 2004)
Kirsner & Dunn (2004): Confidence Contours used to define position of Kormoran Confidence contours over regional map. Contours based on mathematical integration of nine constrains or ‘Source Arguments’ The approach is comparable to triangulation, the backbone of navigation for centuries
Finding Sydney Foundation (2005): Search box for Kormoran Kirsner and Dunn (2004): Predicted position of Kormoran: 26° 04’ South 111° 02’ East Finding Sydney Foundation (2008): Observed position of Kormoran 26° 06’ South 111° 04’ East
Comment By early 2005 the FSF had solved the search definition problem. The predicted position for Kormoran, the recommended search box for Kormoran, and the scientific rationale for these conclusions were provided to Mearns gratis in 2004-2005. In 2004 the Royal Australian Navy advised the FSF that it would endorse a search by the FSF provided that it hired Mearns. Between 2003 and 2007 Mearns advocated eight alternative positions between 17 – 45 nm to the West, South-West and South of the wreck before accepting the weight of evidence that pointed to the area identified by Mearns’ client, the Finding Sydney Foundation in 2004-2005.