An enthusiastic public attended the Codevintec's Workshop held in Rome in October 2014. Edgetech introduced its systems for Marine surveys: Side Scan Sonar, SubBottom Profilers, integrated instruments of the latest technology. The applications are several: Harbour floor survey, dams and embankments, structure monitoring, disaster management, wreck location, archeology, geology, shallow gas detection... Very interesting!

1. An Introduction to
EdgeTech Sonar systems
Nick Lawrence
EdgeTech
Codevintec Workshop
9th October 2014

2. Introduction to EdgeTech
• Industry leader in Underwater Acoustics
• EdgeTech (formerly EG&G Marine Instruments)
– Started in 1966 by Doc Edgerton
• ORE Offshore
– Formed in 1963
Common Technologies
Underwater Acoustics
Digital Signal Processing
• Facilities in Massachusetts and Florida

3. Who uses Sonars ?
Offshore Oil and Gas industry
Regional surveys,
Drill site surveys,
Pipeline Inspections
Side Scan Sonars
Bathymetric systems
Sub-Bottom Profilers
USBL Systems
Military
MCM
Rapid Environmental Assessments
Side Scan Sonars
Bathymetric systems
AUV mounted systems
Port Authorities & Dredging Industry
Wreck location
Pre- and post- dredge surveys
Aggregate extraction surveys
Side Scan Sonars
Bathymetric systems
Sub-Bottom Profilers
Scientific Community
Habitat Mapping
Geological Surveys
Side Scan Sonars
Bathymetric systems
AUV mounted systems
Emergency Services
Search and Recovery Side Scan Sonars

4. Introduction to Side Scan Sonar
– Sideways looking ; 2 sides
– Wide vertical beam
– Narrow horizontal beam
– Towed body

5. EdgeTech Side Scan Frequencies
The selection of the best side scan
sonar frequency for any
application is a compromise
between range and
resolution. Lower frequency
systems provide longer range
(allowing a larger area to be
covered in each pass), whilst
higher frequency systems provide
a higher definition image
Chirp Centre
Frequency
Nominal
Frequency*
Range
120 kHz 100 kHz 250 to 500m
230 kHz 300 kHz 150 to 300m
410 kHz 400 kHz 130 to >200m
540 kHz 600 kHz 100 to 150m
850 kHz 900 kHz 50 to 75m
1600 kHz 1600 kHz 20 to 35m
You will sometimes see the ‘nominal’ frequency quoted
in specifications and marketing material.

6. 4125: Shallow water side scan

7. Applications : Dams and Embankments
?

8. Applications : Dams and Embankments
An excavator moves a 5 to 8 ton
armour rock into position on March
27, the first day of breakwater
repairs on the Sakonnet Point
Breakwater, damaged by hurricanes
Irene in August of 2011, and Sandy
in October of 2012.
EastBay Newpapers

9. Applications : Harbour Floor survey
400 kHz
Data
Data out
to 150m

10. Applications : Structure Monitoring
Cooling
water intakes

11. Side scan sonar in disaster response
• Side scan sonar in Disaster Response
 Wreck location
 Wreck Monitoring
 Body location

12. Applications : Air France AF447
The wreckage of Air France Flight 447 has been found by AUV some 3,900 metres, or
nearly 2.5 miles below the surface of the Atlantic Ocean. A search team led by the
Woods Hole Oceanographic Institution (WHOI, USA) located the downed plane off
Brazil’s northeastern coast.
…They were equipped with Edgetech 120kHz side-scan sonar.
PRESS RELEASE from
Woods Hole
Oceanographic Institution
(WHOI, USA)

13. Applications : Wreck Location

14. Applications : Wreck Location

15. Applications : Wreck monitoring
Wreck of the Yankee
1600 kHz data
from a 4125
600/1600 System.

16. Applications : Wreckage Location

17. Applications : Body Location

18. Towed Sub-Bottom Profiler Systems
3100-P
Portable system
for smaller boats
with a choice of
two different
towfish:
216 2 – 16 kHz
424 4 – 24 kHz
3200-XS
Rack mount
system with a
choice of three
different towfish:
512 500 Hz – 12 KHz
216 2 – 16 kHz
424 4 – 24 kHz

19. Sub-Bottom Profiler Towfish
SB-0512i SB-216S SB-424
Frequency Range 500 Hz – 12 kHz 2 – 16 kHz 4 – 24 kHz
Pulse Type Frequency Modulated
Vertical Resolution
(depends on Pulse selected)
8 – 20 cm 6 – 10 cm 4 – 8 cm
Penetration (typical)
In coarse calcareous sand
In clay
20 m
200 m
6 m
80 m
2 m
40 m
Beam Width
(depends on centre frequency)
16° - 32° 17° - 24° 16° - 23°
Size (cms) 160 x 124 x 47 105 x 67 x 40 77 x 50 x 34
Weight 190 kg 76 kg 45 kg
Cable requirements 3 shielded twisted pairs (5 conductors used)
Maximum Operating Depth 300 m
Tow Speed 3 – 4 knots optimal, 7 knots max. safe operation

20. Applications : Geological Survey
Analysis of the Four Brothers
Slump,
Lake Champlain
Ghosh, Supriti J., 2012.
Unpublished Senior Thesis,
Middlebury College, Middlebury,
VT

21. Applications : Shallow Gas detection
Shallow Gas
“masks”
Acoustic data

22. Bathymetry Applications
• Bathymetric measurements
 Enhanced data for Wreck
location and Wreck Monitoring
 Routine Dredging Monitoring
 Pre- and post- crisis checks to
determine the extent of
changes caused and any impact
on navigable channels

23. Applications : Swath Bathymetry
Sunken overturned
barges
Vertical surfaces
properly imaged

24. Bathymetry and Side Scan Data
• Co-registered SS with Bathymetry
• Longer Arrays for Higher Resolution Imagery
• 1 to 3cm Range Resolution

25. Swath Bathymetry : Dredge Monitoring
Dredge Monitoring of a channel in
Florida, USA
Sand waves can be seen building up in
the dredged channel

26. Swath Bathymetry : Dredge Monitoring
Markings from Dredge
Cutter
Quay wall
Entrance to side
channel

27. Summary
• Sonar Systems allow you to image what is under the water
• Applications
– Side scan sonar for clearance surveys
– Inspection of underwater assets such as pipelines, and embankments
– Side scan sonar in disaster response
– Sub-bottom profiler survey for site suitability
– Sub-bottom profiler inspection of sediment build up behind dams
– Bathymetry and Sub-bottom profiling for Dredging monitoring
– Bathymetric measurements to monitor navigable channels