The Sonardyne RT 6 family provides reliable acoustic release, tracking and recovery for oceanographic instruments, seabed equipment, moorings and subsea structures.
Each RT 6 combines a remotely commanded mechanical release with a Sonardyne 6G acoustic transponder. This allows operators to deploy valuable equipment, acoustically locate and monitor it during the deployment, then command the release when the equipment is ready to be recovered.
The family covers applications ranging from continental-shelf environmental monitoring through to full-ocean-depth moorings, heavy subsea structures, salvage and deepwater construction.
The four available products are:
RT 6-1000: compact, cost-effective release for instruments and equipment deployed to depths of 1,000 m.
RT 6-3000: medium-frequency release for deepwater moorings and subsea structures to 3,000 m.
RT 6-6000: low-medium-frequency release for long-duration deployments to 6,000 m.
RT 6-HD: heavy-duty, 7,000 m-rated release with a 2,500 kg Working Load Limit.
Deploy, Track, Locate and Recover
Acoustic releases are commonly installed between an anchor or ballast weight and the equipment that must eventually be recovered. During recovery, a coded acoustic command is transmitted from the vessel to the release transponder.
Once a valid release command is received, the mechanical release separates the equipment or mooring from its anchor. Positive buoyancy then returns the recoverable section to the surface.
Unlike a basic acoustic release, each RT 6 also functions as a navigation transponder. When used with a compatible Ranger 2 USBL system, the vessel can track and position the release throughout deployment, monitoring and recovery.
This integrated functionality can reduce the need for separate release and tracking transponders on the same equipment frame.
Typical Applications
| Application | Use of an RT 6 Acoustic Release |
|---|---|
| Oceanographic moorings | Secures instrument strings and flotation packages to the seabed until an acoustic recovery command is transmitted. |
| Environmental monitoring | Supports long-term deployment of current meters, hydrophones, CTDs, sediment instruments and other monitoring equipment. |
| Seabed landers and instrument frames | Provides release and USBL tracking for lowered packages and autonomous seabed platforms. |
| Subsea construction | Allows lifting lines, deployment rigging and installed structures to be released without direct intervention. |
| Telecommunications cable work | Supports deepwater cable repair, installation and recovery activities requiring a high-load acoustic release. |
| Salvage and recovery | Can release buoyant recovery packages, marker buoys or lifting lines attached to subsea equipment. |
| Defence and security | Provides secure two-way acoustic control and tracking for remotely deployed subsea assets. |
| Marine scientific research | Enables unattended instrument deployments lasting months or years before recovery. |
Choosing the Right RT 6 Release
| Product | Depth Rating | Working Load Limit | Battery Life | Typical Selection |
|---|---|---|---|---|
| RT 6-1000 | 1,000 m | 150 kg | More than 13 months | Compact instrument packages, coastal monitoring and continental-shelf deployments. |
| RT 6-3000 | 3,000 m | 1,275 kg | More than 32 months | Deepwater oceanographic moorings, instrument frames and subsea structures. |
| RT 6-6000 | 6,000 m | 1,275 kg | More than 32 months | Abyssal monitoring, deep-ocean research and long-duration full-depth moorings. |
| RT 6-HD | 7,000 m | 2,500 kg | More than 32 months | Heavy subsea structures, deepwater construction, cable work and salvage. |
The Working Load Limit is not the same as the maximum safe release load, proof load or breaking load. The complete deployment arrangement, including shackles, bridles, frames, ropes and lifting components, must be assessed as an integrated system.
Compatible Control and Tracking Systems
Depending on the RT 6 model and acoustic frequency, releases can be configured, tested, tracked and commanded using compatible Sonardyne equipment.
- Ranger 2 USBL: enables compatible releases to be tracked, positioned and commanded using an existing vessel USBL system.
- Deck Topside: rugged portable command-and-control system with an over-the-side dunking transducer.
- RT 6 Android application: used with the RT 6-1000 for NFC configuration and supported control workflows.
- iWand: handheld acoustic transponder test and configuration tool used with the deeper RT 6 models.
The correct topside and transducer frequency must be selected for the intended RT 6 model. Medium Frequency and Low Medium Frequency products are not interchangeable with every topside configuration.
RT 6 Family Specification Summary
| Specification | RT 6-1000 | RT 6-3000 | RT 6-6000 | RT 6-HD |
|---|---|---|---|---|
| Depth rating | 1,000 m | 3,000 m operational | 6,000 m | 7,000 m |
| Frequency band | MF | MF | LMF | LMF |
| Working Load Limit | 150 kg | 1,275 kg | 1,275 kg | 2,500 kg |
| Maximum safe release load | 150 kg | 1,700 kg | 1,700 kg | Not separately published on the current product page |
| Battery life | More than 13 months | More than 32 months | More than 32 months | More than 32 months |
| Weight in water | 0.5 kg | 15 kg | 15 kg | 20 kg |
| Primary role | Compact coastal and shelf-water equipment recovery | Deepwater moorings and structures | Full-depth oceanographic moorings | Heavy-load deepwater deployment and recovery |
RT 6-1000
RT 6-1000 is a compact acoustic release transponder for coastal, continental-shelf and general-purpose subsea deployments to depths of 1,000 m.
With a 150 kg Working Load Limit and alkaline battery endurance exceeding 13 months, it is suited to environmental sensors, instrument packages, small moorings and seabed equipment that must remain deployed for a season or a full annual survey cycle.
The unit can be configured and commanded using compatible Deck Topside equipment, the RT 6 Android application or a Ranger 2 USBL system. Its Medium Frequency Wideband 2 signals support more than 300 unique acoustic addresses, helping operators manage multiple nearby deployments.
RT 6-3000
RT 6-3000 is a deepwater acoustic release transponder for instrument moorings, seabed frames and subsea structures deployed to operational depths of 3,000 m.
Its 1,275 kg Working Load Limit supports considerably heavier equipment than the RT 6-1000, while alkaline battery endurance exceeding 32 months makes it suitable for sustained oceanographic and environmental monitoring programs.
The Medium Frequency unit can be commanded and tracked using compatible Ranger 2 USBL systems or operated using Deck Topside with an appropriate dunking transducer.
RT 6-6000
RT 6-6000 is a full-ocean-depth acoustic release transponder for deepwater moorings, seabed equipment and sustained observation programs to depths of 6,000 m.
It provides the same 1,275 kg Working Load Limit as the RT 6-3000 but uses a Low Medium Frequency acoustic system suited to greater slant ranges and deeper deployments.
Battery endurance exceeding 32 months supports multi-year scientific and environmental monitoring, while Ranger 2 compatibility allows the transponder to be located, tracked and commanded from an appropriately equipped vessel.
RT 6-HD
RT 6-HD is Sonardyne’s highest-load and deepest-rated standard acoustic release transponder, providing a 2,500 kg Working Load Limit and operation to 7,000 m.
It is intended for demanding applications including subsea structure installation, heavy equipment recovery, telecommunications cable work, salvage and deepwater sensor monitoring.
The LMF transponder can be tracked and commanded using compatible Ranger 2 USBL systems or operated using a suitably configured Deck Topside system.
