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UnderwaySV

Sound speed profiling from a moving vessel

Avoid survey downtime collecting stationary SV profiles

Near real-time availability of SV profiles to surveyor

UnderwaySV 400 shallow water option 15-400m water

depth

UnderwaySV 700 for deeper profiling

Compact and portable to fit any survey vessel

The Oceanscience UnderwaySV offers vertical sound velocity (SV) profiles in minutes, without ever having

to stop the survey vessel. The latest Valeport Ltd digital time-of-flight sound velocity measurement

technology is combined with the innovative Oceanscience underway sensor deployment system developed

for the UnderwayCTD. The result is a revolutionary tool for hydrographic surveying. Easy to use, portable,

compact, and affordable, the Underway SV saves survey time and promotes a better understanding of

sound speed variability for optimum survey results. State of the art wireless communication allows profiles to

be downloaded to the survey computer automatically as soon as the probe emerges from the water behind

the ship, with no operator involvement required.

UnderwaySV Near Real-Time Profiling

The UnderwaySV probe transmits data to the survey computer automatically after each profile is completed,

through a dedicated wireless link. When the probe emerges from the water, the onboard Bluetooth antenna is

activated and establishes a link to the survey computer up to 50m away. The SV profile is extracted from the

probe and saved on the computer ready for use in the survey software package. In the default profiling mode,

only the valid downcast data are stored on the probe and then downloaded to the computer; this mode allows

SV profiles to be loaded into the survey system with the minimum of subsequent processing.

The probe is shipped with the proprietary Valeport RapidSVLog software and dedicated Bluetooth antenna

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module. Use of a "smart" Bluetooth module means that the probe and remote computer wireless link never

requires resetting or reconfiguration once the first contact with the probe has been established. Wireless

connectivity headaches are eliminated.

UnderwaySV 400 in Action

Using the UnderwaySV 400 in shallow water - real time profiling

Deployment of the UnderwaySV 400 in shallow water. The fully automated

wireless data management system means time saved getting the profile into the

survey system.

UnderwaySV Data Examples

The UnderwaySV minimizes data processing time. Sound velocity profiles are obtained that require no further

editing or processing often required to remove "junk data" at the start or end of the profile. Only the downcast

is typically recorded, with logging activated at a designated pressure (e.g. 1dbar); the profiles are ready to be

used immediately. Examples of UnderwaySV sound speed profiles are shown below, exactly as they are

downloaded from the probe to the survey computer. The shallow profiles on the right were collected at 2 minut

intervals using the UnderwaySV 400 at 12kts.

UnderwaySV Profiler Specifications

The UnderwaySV includes a custom freefall sound velocity probe manufactured by industry leader Valeport

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Ltd. The probe includes a state-of-the art digital time of flight sound velocity sensor, strain gauge pressure

transducer, and optional PRT temperature sensor. An extremely strong titanium housing and aluminum/bronze

nose piece protects the sensors from damage during underway deployment and recovery. The efficient probe

shape results in a very fast drop rate, leading to an exceptionally deep profiling capability with a short

turnaround between casts.

Sound

Velocity (m/s)

Temperature

(C)

Depth

(bar)

Resolution 0.001 0.001 0.001%

Accuracy - Raw Data 0.02 0.01 0.05%

Range 1375 - 1900 -5 - 35 200 bar

Sampling

Rate

SV+P SVP+T Depth

Resolution

Sound velocity only 16Hz x 40cm

Sound velocity +

temperature

32Hz x x 20cm

Visit the Valeport Ltd web site to learn about the UnderwaySV probe system

UnderwaySV 400 Configuration and Operation

The UnderwaySV 400 allows continuous profiling to 400m depth without having to recover the probe onboard

between casts. The freefall probe is dropped from the winch arm and pulls tether line off the UnderwaySV winc

as it falls. The low friction winch system presents very little resistance for the falling probe to overcome and lin

is easily pulled off. When the required profile depth is attained, the winch is reversed and the probe is

recovered. After recovery, when the probe is at the surface just behind the ship, the profile is automatically

downloaded to the survey computer. If only a single cast is required, the probe may be stowed in the probe

holder, otherwise the procedure may be repeated. As the probe descent rate is largely independent of the

vessel speed and is well known, the probe depth can be accurately estimated simply by measuring the elapse

duration of the cast. Typical maximum profiling depths for the UnderwaySV 400 are shown below.

Profile Depth (m)

Speed

(kts)

300 400 500 600 700 800

0

2

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46

8

10

12

UnderwaySV 700 Configuration and Operation

The UnderwaySV 700 shares basic components with the UnderwaySV 400 but the tail spool reloader is added

The tail spool reloader is used to load tether line from the main winch onto the tail spool of the probe. Upon

deployment, the tightly wound line on the probe tail spool pays out as the probe falls. At the same time, tether

line is paid out from the main winch. This deployment method eliminates all drag on the probe from the tether

line, as the line is almost stationary in the water as the probe drops. A fast and constant drop rate of 5.5m/s is

achieved throughout the cast duration. As the probe drops at a constant rate, drop timing can be used to

accurately estimate the probe depth independent of vessel speed. The overall deployment procedure differsfrom the UnderwaySV 400 in that the probe is brought on board for line to be loaded onto the probe tail spool

after each cast. Typical maximum profiling depths for the UnderwaySV 700 are shown below.

Profile Depth (m)

Speed

(kts)

300 400 500 600 700 800 900 1000

0

2

4

6

8

10

12

Click here to learn more about how the Oceanscience Underway profilers work

UnderwaySV 700 in Action

Deep sound velocity profiling using the UnderwaySV 700

Using the tail-spool reloader included in the UnderwaySV 700, profiling down to

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over 700m is possible at survey speeds.

UnderwaySV Deployment in Shallow Water

For deployment in 15-100m water depth, the "Slow-Fall" UnderwaySV profiler option can be chosen. Properly

selected buoyancy modules are simply installed on the probe tail spool to slow the probe descent rate from

5.5m/s to 1m/s.

Watch the UnderwaySV 400 video above to see the "Slow-Fall" modified profiler in action.

Frequently Asked Questions

Have a question about the UnderwaySV? If frequently asked, the answer will be in

the FAQ!

Click here for the FAQ Page

Download

PRODUCT INFORMATION SHEET - UnderwaySV

PRODUCT INFORMATION SHEET - UnderwaySV Configuration Options

PRODUCT INFORMATION SHEET - Valeport RapidSV Probe

APPLICATION NOTE - C & C Technologie s Alaska 2011

APPLICATION NOTE - Norwegian Hydrographic Serv ice 2011

USER GUIDE - UnderwaySV

USER GUIDE - Valeport RapidSV and RapidSVlog

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