Deep Wreck Site WA1003

Introduction

Side Scan of Sub Wreck (81m x 5m x 2m)Side Scan of Sub Wreck (81m x 5m x 2m) Wreck site WA1003 is described by the UKHO as being intact, possibly with two masts, at a charted depth of 46m with the surrounding seafloor being 55m deep. The wreck was located using the sidescan sonar and found to be approximately 10m due east of its recorded position.
 

Detailed Results

Sidescan Sonar and Magnetometer Data

Side Scan of Whole SiteSide Scan of Whole Site The sidescan sonar data consisted of 11 lines, each approximately 500m long and orientated E-W with a 75m range setting. The survey covered an area of approximately 500m x 350m. A further 19 lines orientated N-S were surveyed along the length of the wreck. Seven sidescan sonar anomalies were identified.
 
Magnetometer survey lines were also surveyed over the wreck, with lines orientated N-S. A single magnetic anomaly was identified.
 
The two sidescan sonar and the magnetic anomalies were compared in the GIS and grouped into two sites, both of which ascribed a level of Archaeological Potential:
 
Archaeological PotentialNumber within Study Area
High1
Medium0
Low1
Very Low0
Archaeological Potential Rating of geophysical anomalies within the WA1003 Study Area
 
The wreck is sitting upright on the seafloor in one piece (WA6300). The sidescan surveys show it to be approximately 81m x 5m, standing up to 2m above the seafloor. While it is difficult to determine which end is the bow, it is thought likely that it lies to the north.
 
Magnetometer ResultsMagnetometer Results The acoustic shadow produced by the sidescan sonar shows that a significant amount of structure is still present on the deck of the vessel. However, it is not clear exactly what those structures are.
 
This site (WA6300) has a magnetic anomaly of 2869nT, confirming that this vessel is metallic. The size of the magnetic anomaly produced by this wreck obscures any other smaller magnetic anomalies that may lie nearby.
 
Although the wreck appears to be intact, one site (WA6301) that lies just 5m away is interpreted as a small piece of associated debris.
 

Multibeam Data

The main wreck site (WA6300) was located within the multibeam data only a few metres from the position as determined using the sidescan sonar data. The multibeam data shows that the wreck is approximately 58m x 5m x 3m.
 
Multibeam ResultsMultibeam Results The width and height measurements are very similar to the sidescan sonar measurements but there is a difference between the length measurements. The length of the wreck as measured from the sidescan sonar data ranged from 70m to 87m, all greater than the multibeam measurement of 58m, which is likely to be more accurate.
 
The differences between the length measurements are due to the different angles at which the wreck has been imaged and the resulting image distortions. The sidescan surveyed it at an oblique angle from different directions while the multibeam surveyed it from above.
 
Multibeam results presented as pointsMultibeam results presented as points The multibeam survey covered an area of approximately 650m x 450m. The depth of the seafloor ranged from 52m to 58m. The Reson 8125 used for this project has a beamwidth of 0.5° and therefore the footprint of the beams over this site was approximately 0.7m.
 
Viewing the multibeam data as points rather than as a gridded surface does not provide any more detail on the structures present on the deck of the vessel. It does, though, show that the highest point on the vessel, presumably the bridge, is 45m from the bow.
 
For information on the ROV survey of this site click here.