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.

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 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.

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.

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 minute intervals using the UnderwaySV 400 at 12kts.




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

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 winch as it falls. The low friction winch system presents very little resistance for the falling probe to overcome and line 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 elapsed 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
4
6
8
10
12

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 differs from 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

Deep sound velocity profiling using the UnderwaySV 700 Using the tail-spool reloader included in the UnderwaySV 700, profiling down to over 700m is possible at survey speeds.

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.

Have a question about the UnderwaySV? If frequently asked, the answer will be in the FAQ! Click here for the FAQ Page

	PRODUCT INFORMATION SHEET - UnderwaySV
	PRODUCT INFORMATION SHEET - UnderwaySV Configuration Options
	PRODUCT INFORMATION SHEET - Valeport RapidSV Probe
	APPLICATION NOTE - C & C Technologies Alaska 2011
	APPLICATION NOTE - Norwegian Hydrographic Service 2011
	USER GUIDE - UnderwaySV
	USER GUIDE - Valeport RapidSV and RapidSVlog