west cape york marine park – multibeam survey · bathymetry data, to apply sbet files and for...

Australian Institute of Marine Science

West Cape York APM – Multibeam Mapping Field report Issue Rev 1 April 2020

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West Cape York Marine Park – Multibeam Survey

Simon Harries, Mark Case, Jamie Colquhoun

A document prepared for Parks Australia

APRIL 2020


West Cape York APM – Multibeam Mapping Field report Issue Rev 1 April 2020

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PMB No 3

Townsville MC QLD 4810

PO Box 41775

Casuarina NT 0811

Indian Ocean Marine Research Centre

University of Western Australia, M096

Crawley WA 6009

This report should be cited as:

Harries, S., Case, M. & Colquhoun, J., (2020). West Cape York Marine Park – Multibeam Survey

Report Rev 1 April 2020. Report to Parks Australia. pp. 14 incl. appendices.

© Copyright: Australian Institute of Marine Science (AIMS) [2020]

All rights are reserved and no part of this document may be reproduced, stored or copied in any

form or by any means whatsoever except with the prior written permission of AIMS

ACKNOWLEDGEMENTS

The master and crew of the RV Solander who were invaluable in completing the survey safely and

efficiently. Joshua Biggs for his assistance in acquiring the multibeam data.

DISCLAIMER

While reasonable efforts have been made to ensure that the contents of this document are factually

correct, AIMS does not make any representation or give any warranty regarding the accuracy,

completeness, currency or suitability for any particular purpose of the information or statements

contained in this document. To the extent permitted by law AIMS shall not be liable for any loss,

damage, cost or expense that may be occasioned directly or indirectly through the use of or reliance

on the contents of this document.

Revision History: Name Date

Issue

Rev 1

Prepared by Mark Case 30/4/2020

Issue

Rev 0

Prepared by: Simon Harries and Mark Case

5/03/2020

Reviewed by: Karen Miller 30/03/2020

Approved by: Karen Miller

7/04/2020

Revised by: Parks Australia April 2020

Cover photo: Solander in Gove Harbour. Image: AIMS


West Cape York Marine Park – Multibeam Survey Report Issue Rev 1 April 2020

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CONTENTS

1 Introduction .................................................................................................................................... 1

2 Methodology ................................................................................................................................... 2

2.1 Multibeam bathymetry and backscatter ................................................................................ 2

2.1.1 Survey areas and assessment. ........................................................................................ 2

2.1.2 Line spacing and planning ............................................................................................... 2

2.1.3 Multibeam acquisition systems and settings .................................................................. 3

2.1.4 Sound Velocity ................................................................................................................ 4

2.1.5 Multibeam Processing ..................................................................................................... 4

2.2 Safety ...................................................................................................................................... 4

3 Results and conclusions .................................................................................................................. 5

3.1 Bathymetry ............................................................................................................................. 5

3.1.1 Carpentaria Shoal ............................................................................................................ 5

3.1.2 Additional Multibeam Transects ..................................................................................... 7

3.2 Benthic Habitats ...................................................................................................................... 7

3.3 Sound Velocity ........................................................................................................................ 9

3.4 Conclusions ........................................................................................................................... 10

4 References .................................................................................................................................... 11

5 Appendices .................................................................................................................................... 13

5.1 MBES acquisition log ............................................................................................................. 13



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TABLE OF FIGURES

Figure 1: Location of the survey. ............................................................................................................ 1

Figure 2: R2Sonic 2026 mounted to the (raised) moonpool carriage of RV Solander. .......................... 3

Figure 3: Multibeam bathymetry (gridded at 1m) for Carpentaria Shoal.............................................. 5

Figure 4: 2D profile across Carpentaria shoal, diagonally across the widest extents from Southwest

to Northeast. Depths are below approximate mean sea level (based on AusGeoid09). ....................... 6

Figure 5: 3D representation of Carpentaria Shoal. ................................................................................ 7

Figure 6: Additional Multibeam Transects south of Carpentaria Shoal. ................................................ 7

Figure 7: Carpentaria Shoal plateau benthos - 50 m diver transect. Photographer: Graham Edgar

(RLS) ........................................................................................................................................................ 8

Figure 8: Carpentaria Shoal plateau. Typical hard corals, filter feeders and invertebrates of the

plateau. Photographers: Graham Edgar & Andrew Green (RLS) ............................................................ 9

Figure 9: Sound Velocity Profiles collected during the survey. ............................................................ 10



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1 INTRODUCTION

The Australian Institute of Marine Science (AIMS) was contracted by Parks Australia to undertake

opportunistic multibeam bathymetry mapping of West Cape York Marine Park during a transit voyage

of the Research Vessel Solander from Thursday Island to Darwin, planned for January-February 2019.

Due to extreme weather conditions it was not feasible to survey within the West Cape York Marine

Park, and instead an area within the more sheltered southern region of the Wessel Marine Park was

surveyed (Case, et al., 2019). Another opportunity presented in November 2019 to map a portion of

the West Cape York Marine Park on another transit to Thursday Island on Solander Trip 7294, this time

during fine weather.

The primary objective of the survey was to undertake approximately 24hrs of Multibeam Echo

Sounder (MBES) surveying to quantitatively map parts of the seafloor within the West Cape York

Marine Park to build knowledge of the values of the park and to provide data that can inform future,

targeted bathymetric and biological surveys. In this survey we comprehensively mapped Carpentaria

Shoal, as well as the sparsely surveyed grounds to the south (Figure 1).

This report details the operational aspects of the survey and provides a summary of the MBES data

that was acquired and processed.

Figure 1: Location of the survey.



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2 METHODOLOGY

2.1 Multibeam bathymetry and backscatter

2.1.1 Survey areas and assessment.

Survey planning for the West Cape York Marine Park was undertaken in consultation with Parks

Australia to optimise value of new data relative to marine park zones, habitats and depth gradients,

existing multibeam data, and to prevent surveying where MBES data already existed.

The following websites and data portals were queried about multibeam and bathymetry data and its

availability and quality;

AusSeabed Marine Data Discovery - Bathymetry and Backscatter Data Access

https://marine.ga.gov.au/#/

CSIRO - Data Access Portal

https://data.csiro.au/dap/search?kw=Bathymetry/Seafloor%20Topography

Australian Hydrographic Office http://www.hydro.gov.au/business-

publications/hydroscheme.htm

Several layers of information were download and assessed. Transit data from the CSIRO – Data Access

Portal was of a poor quality and didn’t affect planning. The RAN had recently completed multibeam

surveys in the Northern region of the West Cape York Marine Park and data should be available late

June 2020. Based on coverage of existing data and potential areas of biological interest, it was decided

to survey in the central area of the marine park focusing on Carpentaria Shoal and the poorly surveyed

area 15km south of Carpentaria Shoal.

2.1.2 Line spacing and planning

The bathymetric MBES survey of Carpentaria Shoal was planned for an average speed of 6 knots, with

minimum overlap of 25% between survey lines. To cover the survey area a total of 21 lines of

approximately 4km in length at a spacing of 100m were completed over the shoal and the surrounding

area (Figure 1), one additional crossline traversing the entire area diagonally was also surveyed for QC

in processing. The Carpentaria shoal survey box covers an area of approximately 10.5km2.

For the remainder of the survey, targeting an area south of Carpentaria Shoal, four lines of

approximately 29km in length were completed at a spacing of 1km. The coarse spacing was chosen in

order to cover as large an area as possible given the time available, and to maximise the possibility of

finding features of interest. MBES data was also acquired during the transit from Carpentaria Shoal to

the southern survey area, and on the transit out after completing the 24hr survey. An additional six

shorter lines were also conducted at 150m line spacing over the reported position of a wreck in the

SW of the southern survey area to map this area of interest in higher detail.



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2.1.3 Multibeam acquisition systems and settings

The MBES survey was conducted using the AIMS R2Sonic 2026 multibeam echo sounder (MBES),

mobilised from the carriage within the moon pool of AIMS research vessel RV Solander. The 2026 is a

high-end broadband multibeam system which operates on user-selectable frequencies ranging from

90 to 450 kHz, with up to 1024 equidistant- or equiangular-spaced beams across a variable swath (10°

to 160°).

For both survey locations the MBES system was operated in ultra-high-density mode at a frequency

of 450 kHz. The MBES sector was set at between 130° and 160° (depth dependant) for the duration of

the survey. Vessel speed during the survey was variable between 5-7 knots (nominally 6 knots)

depending on sea state.

Figure 2: R2Sonic 2026 mounted to the (raised) moonpool carriage of RV Solander.

All installation offsets for the multibeam system as well as operational parameters used on a line by

line basis are provided in the acquisition log (MBES acquisition log, Appendix 5). Multibeam operations

were conducted for 24 hours commencing at 0240 on 18/11/2019 (UTC) .

Position and orientation data were acquired by an Applanix PosMV OceanMaster with satellite aiding

via Fugro Marinestar G4+, which provides high accuracy real-time position (of better than 15cm

vertical and 10cm horizontal in real-time) and orientation at 200 Hz. This position and orientation

information was used in real-time by the multibeam for time-stamping and pitch and roll

compensation, in the acquisition software for navigation and real-time generation of digital terrain

models as well as being logged using Applanix POSView software, for post-processing after the

completion of the survey.



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Raw multibeam data (including bathymetry and backscatter) from the MBES was acquired in QINSy

(QPS, Netherlands, version 8.18.2), as well as time, position and attitude data from the POSMV. Raw

multibeam data was logged in QPS database (.db) file format. Raw multibeam data was referenced to

the ITRF Ellipsoid by the POSMV, this method of sounding reduction does not require the

measurement of the vessel draft or squat and water level (including tides) therefore these parameters

were not recorded during this survey.

2.1.4 Sound Velocity

During MBES surveys, sound velocity profiles (SVPs) are required to account for refraction as the speed

of sound changes through the water column. For this survey a total of seven SVPs were collected

during the 24hr period using an AML Minos X sound velocity profiler and applied immediately. Sound

velocities at the MBES head were collected continuously with an AML Micro-X sound velocity sensor

and logged in the MBES acquisition software.

2.1.5 Multibeam Processing

POSPac MMS (Applanix, Canada, version 8.4 SP1 Hotfix) was used to post-process the navigation data

from the POSMV, to generate smoothed best estimate of trajectory files (SBET) and for final vertical

datum reduction. Qimera (QPS, Netherlands, version 1.7.6) was used for processing the multibeam

bathymetry data, to apply SBET files and for cleaning. A weak spline was applied to remove data spikes,

data was filtered by intensity and noisy data was manually cleaned where necessary, finally a

Combined Uncertainty and Bathymetric Estimator (CUBE) was used in Qimera for calculation of total

propagated uncertainty and the creation of a final surface. Final gridded data products were generated

with optimal resolution varying by the water depth (and resultant sounding density) of the individual

survey areas. Final soundings were reduced to approximate mean sea level using the AUSGeoid 2009

model (Brown, Featherstone et al. 2011) in POSPac via a 14-point transformation.

Multibeam backscatter was processed from R2Sonic Snippets™ data acquired simultaneously to the

bathymetry (and therefore using the same settings – see (MBES acquisition log, Appendix 5.1).

Backscatter processing was completed in QPS FM Geocoder Toolbox (FMGT - QPS, Netherlands,

version 7.8.10) using default settings.

2.2 Safety

In accordance to AIMS safety procedures, Simon Harries as cruise leader completed a task risk

assessment for the survey. While in the field, AIMS staff followed the AIMS’s field safety guidelines

and fitness for work policies, including the identification and reporting of any safety issues. No

incidents or problems were encountered during the course of the fieldwork.



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3 RESULTS AND CONCLUSIONS

3.1 Bathymetry

3.1.1 Carpentaria Shoal

The multibeam survey details the morphology of Carpentaria Shoal and surrounds providing precise

depths of shoal features. Carpentaria Shoal covers 2.2km2 down to 30m depth and the flat plateau on

top of the shoal covers 1km2 in depths between 15m and 18m. Across the shallow region on top of

the plateau there is a complex arrangement of low relief ridges and small bommies. The seabed

around the shoal has a steep transition from the plateau rim down slope to a generally flat area

between 28m to 35m in depth, apart from a slightly more rugose area in the south western region of

the survey. Carpentaria Shoal appears to be consistent with patch reef geomorphology that is found

in the southern region of the Gulf of Carpentaria (Harris et al., 2004).

Figure 3: Multibeam bathymetry (gridded at 1m) for Carpentaria Shoal.



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Figure 4: 2D profile across Carpentaria shoal, diagonally across the widest extents from Southwest to Northeast.

Depths are below approximate mean sea level (based on AusGeoid09).



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Figure 5: 3D representation of Carpentaria Shoal.

3.1.2 Additional Multibeam Transects

Multibeam transect lines were collected approximately 15km to the south of Carpentaria Shoal. The

east-west transects were planned and conducted at 1km spacing with the option of infill lines for areas

of interest. All transects revealed a generally flat homogeneous area with a gentle slope deepening

from east to west, so no addition infill lines were collected. Additional shorter lines were conducted

at 150m line spacing over a reported position of a wreck (Aus. Chart 700) in the south west of the

survey area, mapping this area of interest in higher detail. No evidence of a wreck was found.

Figure 6: Additional Multibeam Transects south of Carpentaria Shoal.

3.2 Benthic Habitats

Carpentaria Shoal supports light-dependent benthic communities across the shallow region of the

shoal plateau. Multibeam data suggests a distribution of fine-scale rugosity across the top of the

plateau and appears similar to mesophotic shoals in the northern region of Australia.



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In 2015 Reef Life Survey (RLS) conducted a dive survey of the shallow plateau which included 2 x 50m

benthic transects with photo‐quadrats taken every 2.5m. Digital photo‐quadrats were taken vertically‐

downward from a height equating to a surface area of approximately 0.3 m x 0.3 m. The transects

were surveyed on the plateau of the shoal in 17m and 17.5m depths. 22 downward facing photos and

one panoramic photo were collected from the transect at 17m depth and 20 downward facing photos

were collected from the transect at 17.5m depth.

Figure 7: Carpentaria Shoal plateau benthos - 50 m diver transect. Photographer: Graham Edgar (RLS)

The hard substrate of the shallow plateau of Carpentaria Shoal typically supports carbonate

sediments, hard corals and moderate densities of mixed filter feeding organisms (soft corals &

sponges), ascidians, crustose coralline algae (encrusting & branching), a diverse fleshy algal

assemblage, urchins, polychaeta worms and other invertebrates were also present.

Each downward photo from the RLS benthic transects was examined and benthos identified where

possible. The benthic habitat in the limited number of benthic photos from a small area of the plateau

was dominated by five main Scleractinia hard corals from the genus Turbinaria, Favia, Goniastrea,

Montipora and Alveopora. Other less abundant hard corals encountered were from the genus

Seriatopora, Euphyllia, Porites, Acropora, Lobophyllia, Psammocora, Cynarina and Favites.



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Figure 8: Carpentaria Shoal plateau. Typical hard corals, filter feeders and invertebrates of the plateau.

Photographers: Graham Edgar & Andrew Green (RLS)

Filter feeders were common with a soft coral from the Family Xeniidae being the most common

benthos occurring in 32 of the 42 photos analysed. Soft corals from the family Alcyoniidae were the

second most common benthos and soft coral. Other soft corals encountered on the survey were from

the family’s Gorgoniidae, Ellisellidae, Plexauridae and Tubiporidae. Xestospongia and Callyspongia

sponges were common however there were many other encrusting, simple erect and branching

sponges visible.

There was a diverse algal assemblage of red, green and brown algae with the genus Padina most

recognizable. Other invertebrates present to a lesser extent were ascidians, urchins from the genus

Diadema, polychaete worms and corallimorphs.

3.3 Sound Velocity

Sound velocities for the entire area, and in particular, over Carpentaria Shoal were highly variable,

which was counteracted by collecting a greater than usual number of Sound Velocity Profiles. This

should be considered for future surveys, and alternative techniques for sound velocity collection (such

as a Moving Vessel Profiler) should be considered. Sound Velocity profiles collected over both survey

areas are shown in Figure 9.



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Figure 9: Sound Velocity Profiles collected during the survey.

3.4 Conclusions

This survey has produced detailed bathymetry of Carpentaria Shoal and other areas of the West Cape

York Marine Park, which will be important data to inform future surveys as well as Marine Park

management into the future. Interestingly the survey was unable to locate a chartered wreck in the

marine park, highlighting the lack of knowledge of the park generally.

We have characterised some interesting seabed features associated with Carpentaria Shoal, although

to understand their biological and ecological significance will require additional data. We were able to

incorporate Reef Life Survey imagery to provide some detail on the benthic communities associated

with shallow areas of Carpentaria Shoal and this revealed diverse coral-dominated ecosystems.

However, further research is required to properly characterise the benthic communities in the

northern half of the Gulf of Carpentaria. On Carpentaria shoal a series of 1500m video transects

producing high resolution digital still images should be conducted across the shallow plateau and

down the slope to at least the 50m contour or beyond, allowing the transitional biological

communities to be characterized. This would enable us to characterise the different benthic habitats

associated with the differing depth and light regimes, from the shallowest flat plateau habitats over



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the crest and down the slope capturing all the habitats associated with Carpentaria Shoal. Similarly,

imagery of the seemingly featureless areas in the southern study area would also provide information

about the nature of the seabed and associated biological communities.

Other shoals and areas of diversity within West Cape York Marine Park and adjacent to the marine

park need to be surveyed to provide a more statistically robust and comparative evaluation of the

benthic communities that are present. Planning to determine appropriate survey areas in the northern

half of the Gulf of Carpentaria in the future would need to be completed. Further seabed habitat

surveys should include additional multi-beam sonar and a combination of diver visual census, towed

video with high resolution digital still imagery, and Baited Remote Underwater Videos (BRUVS)

depending on habitat type and depth. This would allow a more thorough understanding of the

communities that make-up these remote areas.

Very little is known about these remote mesophotic benthic communities within the West Cape York

Marine Park and adjacent areas, which is reflected in the lack of science literature associated with the

areas. Here we have shown a diversity of habitats exist within the marine park, which likely support

important marine communities. In order to make more informed management decisions further

surveys are required to fill in the knowledge gaps.

4 REFERENCES

Brown, N.J., Featherstone, W.E., Hu, G. & Johnston, G.M., 2011. AUSGeoid09: a more direct and

more accurate model for converting ellipsoidal heights to AHD heights. Journal of Spatial

Science, 56(1): 27-37.

Case, M., Harries, S. and Miller, K. (2019) Wessel Marine Park Multibeam Survey. Report to Parks

Australia. 13 pp

Edgar, G., 2015. Carpentaria Shoal (quadrat survey images). [ONLINE]

http://rls.tpac.org.au/pg/912345834/zip/ Reef Life Survey Foundation. [Accessed 24 February

2020]

Green, A. & Giosio, C., 2015. Carpentaria Shoal (quadrat survey images). [ONLINE]

http://rls.tpac.org.au/pg/912345835/zip/ Reef Life Survey Foundation. [Accessed 24 February

2020]

Harris, P.T., Heap, A.D., Wassenberg, T. & Passlow, V., 2004b. Submerged coral reefs discovered in

the Gulf of Carpentaria, Australia. Marine Geology, 207, 185-191.

Heap, A., Daniell, J., Mazen, D., Harries, P., Sbaffi, L., Fellows, M. & Passlow, V., 2004200.

Geomorphology and Sedimentology of the Northern Marine Planning Area of Australia: review

http://rls.tpac.org.au/pg/912345834/zip/

http://rls.tpac.org.au/pg/912345835/zip/



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and synthesis of relevant literature in support of regional Marine Planning. Record 2004/11.

Geoscience Australia, Canberra.

Picard, K., Austine, K., Bergersen, N., Cullen, R., Dando, N., Donohue, D., Edwards, S., Ingleton, T.,

Jordan, A., Lucieer, V., Parnum, I., Siwabessy, J., Spinoccia, M., Talbot-Smith, R., Waterson, C.,

2018. Australian Multibeam Guidelines. Record 2018/19. Geoscience Australia, Canberra.

Pitcher, C.R., Haywood, M., Hooper, J., Coles, R., Bartlett, C., Browne, M., Cannard, T., Carini, G., Carter, A., Cheers, S., Chetwynd, D., Colefax, A., Cook, S., Davie, P., Ellis, N., Fellegara, I., Forcey, K., Furey, M., Gledhill, D., Hendriks, P., Jacobsen, I., Johnson, J., Jones, M., Last, P., Marks, S., McLeod, I., Sheils, J., Sheppard, J., Smith, G., Strickland, C., Van der Geest, C., Venables, W.,Wassenberg, T., Yearsley, G. (2007). Mapping and Characterisation of Key Biotic & Physical Attributes of the Torres Strait Ecosystem. CSIRO/QM/QDPI CRC Torres Strait Task Final Report.145 pp.



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5 APPENDICES

5.1 MBES acquisition log

Date (UTC) Time (UTC) Line Name / Event Frequency Sector Speed (kn) Pulse Width

Power Gain Abs Spreading

18/11/2019 240 SVP

252 Shoal_Crossline_0004 450 140-145 6.5 100 206-209 5 180 25

321 SVP

329 Shoal_005 450 140-145 6.5 100 206-209 5 180 25

331 Shoal_006 451 140-146 6.5 100 206-210 5 180 25

355 Shoal_1_007 450 140-145 6.5 100 206-209 5 180 25

418 Shoal_2_008 450 130-140 6.5 100 206-209 5 180 25

441 Shoal_3_009 450 130-160 6.5 100 206-209 5 180 25

504 Shoal_4_010 450 130-140 6.5 100 206-209 5 180 25

525 Shoal_5_011 450 130-140 6.5 100 206-209 5 180 25

547 Shoal_6_012 450 130-140 6.5 100 206-209 5 180 25

610 Shoal_7_013 450 130-140 6.5 100 206 5 180 25

632 Shoal_8_014 450 140-155 6.5 100 206 5 180 25

657 Shoal_9_015 450 140-155 6.5 100 206 5 180 25

719 Shoal_10_016 450 140-160 6.5 100 206 5 180 25

742 Shoal_11_0017 450 140-155 6.5 100 206-209 5 180 25

806 SVP

818 Shoal_12_019 450 140-155 6.5 100 206-209 5 180 25

840 Shoal_13_020 450 140-155 6.5 100 206-209 5 180 25

902 Shoal_14_021 450 130-140 6.5 100 206-209 5 180 25

924 Shoal_15_022 450 130-135 6.5 100 206 5 180 25

946 Shoal_16_023 450 130-135 6.5 100 206 5 180 25

1008 Shoal_17_024 450 130-135 6.5 100 206 5 180 25



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1031 Shoal_18_025 450 125-130 6.5 100 206 5 180 25

1053 Shoal_19_026 450 130 6.5 100 206 5 180 25

1117 Shoal_20_027 450 130 6.5 100 206 5 180 25

1141 Shoal_21_028 450 130-135 6.5 100 206 5 180 25

1205 Shoal_22_029 450 130 6.5 100 206 5 180 25

1227 Shoal_23_030 450 130 6.5 100 206 5 180 25

1251 Shoal_24_031 450 130 6.5 100 206 5 180 25

1316 Shoal_25_032 450 130-135 6.5 100 206 5 180 25

Carpentaria Shoal

Complete

1401

WCY_South_Crossline_033 450 130 10.5 / 6.5 100 209 5 186 25

1506 SVP

1521 WCY_South_0034 450 135-140 6.5 100 209 5 186 25

1755 WCY_South_1_0035 450 135-140 6.5 100 209 5 186 25

2036 SVP

2047 WCY_South_2_0036 450 135-143 6.5 100 209 5 186 25

2320 SVP

2327 WCY_South_3_0037 450 133-143 6.5 100 209 5 186 25

19/11/2019 207 WCY_Search_7 450 133-143 6.5 100 209 5 186 25

219 WCY_Search_1_B 450 133-143 6.5 100 209 5 186 25

228 WCY_Search_2_B 450 133-143 6.5 100 209 5 186 25

237 WCY_Search_8 450 133-143 6.5 100 209 5 186 25

246 WCY_Search_1_A 450 133-143 6.5 100 209 5 186 25

254 WCY_Search_2_A 450 133-143 6.5 100 209 5 186 25

300 WCY_South_5 450 133-143 6.5 100 209 5 186 25

318 Survey End

318 Transit 320 130 10.5 100 203 5 145 25

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