It is now two years since the wreck of Endurance was found and Deep Ocean Search take this opportunity to make clear the process by which the area to be searched was defined.
The Falkland Heritage Trust engaged DOS to produce a search box and this work was led by Peter Cope with the input of Frank Reed. This study was designed to determine any corrections which should be applied to navigator Frank Worsley‘s, published sinking position.
The largest correction was made to allow for ice drift, continuing to the South and then slowing and turning northwards during the period 19 – 21 October when no sights could be taken.
The other principal uncertainty involved the effect of chronometer error.
Worsley’s recoded workings to establish chronometer error by occultation were examined by Frank Reed, a noted authority on 19th century navigational practice, consulted by DOS for an overall view of the accuracy of Worsley’s observations and in particular for the specific purpose of establishing the required correction to Longitude due to chronometer error. Having taken into account the effect on the timing of occultation from the variations in the profile of the lunar limb, Frank was able to recommend a correction to Longitude of the sinking position by 1.8nm to the East: this proved to be accurate in relation to the actual located position of the wreck, and DOS would like top record their appreciation of Frank Reed’s contribution to the success of the project. Caption: Frank Worsley
Corrections were suggested by the re-navigation team and were applied to produce a preliminary search box.
On review, the senior management of DOS made a few changes in orientation and size to produce the final search area, which was published internally for the use of the search team, led by Nicolas Vincent. On arrival at the Endurance site, the team deployed the AUV to run survey lines through this defined search box. The wreck of Endurance was found within this area. The Endurance wreck was found 5.6nm to the South East of Worsley’s last known position. The post-discovery study by Dr Marc De Vos et al. has shown that the chronometer error had in fact less impact than the effect of ice drift.
It should be noted that at no time was advice received from third parties regarding the location of the area to be searched, nor were any changes made to DOS management’s final search box.
DOS would like to thank all those who were involved in the definition of the search area, and also those who worked so hard to locate the wreck on site; an excellent team effort and an excellent result.
