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RT 6-3000

Acoustic release transponder

Engineered for: Seabed, Structure

Deep water instrument mooring or structure installation; RT 6-3000 takes the hard work out of your deploying ocean sensors and heavy lifting. It features an impressive battery life of over 32 months and a depth rating of 3,000 m.

At a glance

Tested, loaded, deployed and released with Deck Topside

Also works Sonardyne Ranger 2 USBL to deploy, track and command

Highly reliable release mechanism design; thousands in service globally

Working Load Limit 1,275 kg (4:1)

Depth rated to 3,000 m

External battery disconnect to maximise battery life; no need to open unit

Deploy, track, moor and recover your equipment

Want to know more?

Benefits of RT 6-3000 for your operations

Choice of topsides

You can use our rugged Deck Topside or if you've got access to a Ranger 2 USBL system on your survey or research vessel, then you have everything you need to control your RT 6-3000.


RT 6-3000 is more than just an acoustic release. It can be tracked with our Ranger 2 USBL making relocating and recovering it fast and simple.

High WLL

Use it with our Heavy-Duty Release Frames and significantly increase your Working Load Limit when deploying seabed structures.


Acoustic release transponders are a vital pieces of ocean equipment; relied upon by energy, defence and science users to moor valuable equipment strings for years at a time, and when commanded to do so, reliably return equipment and logged data to the surface.

Transponders need to be tough, reliable and easy to work with. RT 6-3000 meets these requirements.

Part of our new range of acoustic releases, RT 6-3000 combines the extensive mechanical design track record of our renowned ORTs and DORTs with the flexibility of our 6G platform, resulting in enhanced battery life and perhaps most significantly, compatibility with our Ranger 2 USBL family.

With RT 6-3000,  you can your Ranger 2 USBL to deploy, track, locate and command the instrument – removing the need for a separate topside unit. If you don’t have access to a Ranger 2 USBL,  our rugged and lightweight Deck Topside with an over-the-side dunker is all you need to both configure and command RT 6-3000s.

RT 6-3000s are most commonly used to anchor oceanographic moorings to the seabed. However, their compact size and compatibility with Ranger 2 makes them ideal for incorporation into instrument frames or lowered platforms to enable deployment of sub-system packages.

Depth rated to 3,000 m, the maximum slant range for operation is dependent on the noise environment and topside used, but ranges to 4,500 m should normally be achievable.

Standard features include a Working Load Limit of 1,275 kg (at 4:1) and a spring-assisted release mechanism. RT 6-3000 is compatible with our standard tandem and high-load release frames for scenarios requiring a higher WLL. Speak to us about your requirements as custom frames are also an option.

A battery disconnect fob is located on the transducer and uses an internal magnetic switch to electronically disconnect the battery when not in use. This means you do not have to open the unit to manually disconnect the battery, saving time and reducing the risk of incorrect re-assembly.

RT 6-3000s use the same trusted spring-assisted release mechanism that has been in service for many years and used on thousands of Sonardyne transponders globally.

Why invest


  • Medium Frequency (19-34kHz) band, Wideband 2

  • Omni-directional transducer. Track it all the way to the surface

  • Sonardyne Wideband 2 signal architecture supporting over 300 unique addresses

  • Compatible with any Ranger 2 USBL system and Deck Topside


  • 700 x 142 mm, 15 kg weight in water

  • Aluminium bronze, duplex stainless steel construction. ROHS compliant

  • Configured with iWand hand-held acoustic transponder test and configuration device

  • Compatible with our standard tandem and high-load release frame


  • 3,000 m depth rated

  • 4,500 m working range

  • >32 months battery life; alkaline battery

  • 1,275 kg Working Load Limit

  • Secure and robust two-way acoustic Communications. Only release what you want to release


  • What’s in the box: RT 6-3000, shackles, manual on USB

  • Warranty: 1 year return to Sonardyne service centre

  • ITAR Controlled: No

  • UK Export License: Not required


Feature Type 8320-3411
Depth Rating 3,000 m*
Maximum Slant Range 4,500 m
Operating Frequency MF (20–34 kHz)
Transducer Beam Shape Hemispherical
Transmit Source Level (dB re 1 µPa @ 1 m) 186 dB
Tone Equivalent Energy (TEE) 192 dB
Receive Threshold (dB re 1 µPa) <90 dB
Working Load Limit (4:1) 1,275 kg
Proof Load 2,550 kg
Breaking Load 5,100 kg
Maximum Safe Release Load 1,700 kg
Battery Life (Alkaline) >32 months active
Inclinometer Accuracy ±5°
Surface Unit Deck Topside, Ranger 2 USBL
Mechanical Construction Aluminium bronze and duplex stainless steel
Operating Temperature -5 to 40°C
Storage Temperature -20 to 55°C
Dimensions (Length x Diameter) 700 x 142 mm (27.5 x 5.6”)
Weight in Air/Water 20/15 kg
Standards CE Marked to EN-60945, EN-61010
Options Shallow Water Deck Kit (Deck Topside) – 602-0175
Mid Water Deck Kit (Deck Topside) – 602-0179
Heavy Duty Release Frames (7.5 T, 15 T and 25 T)
*RT 6-3000 is pressure rated to 4,000 m; however, due to operating range constraints of MF, its use at depths greater than 3,000 m is not recommended.

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Deploy, track, moor and recover your equipment