Mapping the future for seagrass beds in Plymouth Sound

Seagrass beds are incredibly important ecosystems that offer a range of ecological benefits. Not only do they provide crucial habitats for a diverse array of marine wildlife, especially in coastal areas like Plymouth Sound, they can also store carbon, helping to mitigate the effects of climate change. These underwater meadows serve as nurseries for many species of fish in the early stages of their life, offering them protection and abundant food sources. Additionally, seagrass beds help to stabilise the seabed with their root systems, preventing coastal erosion and maintaining water quality by trapping sediments and nutrients.

However, despite their importance, locating and monitoring seagrass beds using traditional methods, such as survey boats, presents significant challenges. Seagrass typically grows in shallow waters, which can make it difficult for boats to navigate close enough to the shore to obtain accurate data. Traditional survey boats are often large and cumbersome, making them hard to manoeuvre in shallow or rocky areas. This limitation can result in incomplete or inaccurate assessments of seagrass distribution and health.

Furthermore, the process of using boats for surveying can be time-consuming and labour-intensive. It often requires multiple trips and extensive manual labour to map out the seagrass beds accurately. The visibility in shallow waters can also be poor due to water turbidity, further complicating the survey efforts and leading to potential underestimation of seagrass coverage.

Finding a solution…

This is where Sonardyne and Wavefront Systems come in. The solution, which combines Sonardyne and Wavefront technology, is a survey boat carrying Solstice MAS™ (Multi-Aperture Sonar) as well as a SPRINT-Nav Mini mounted to a pole, deployed over the side of the boat; this maps the chosen area in 200 m wide strips. Once this survey has been completed, the sonar data that has been captured is then processed to create a map of the seagrass in a GIS. A Remotely Operated Vehicle (ROV) is then sent to the same area to ground truth features on the seabed to check that they are how they have been interpreted by Solstice MAS. The ROV is fitted with SPRINT-Nav Mini, allowing us to track its position underwater and guide it, using the map, to the features identified by Solstice; the ROV is also fitted with a camera and the recorded video can be used to create 3D models of the seabed.

Wavefront Systems’ Solstice MAS uses sound signals to produce high-quality images of the seabed, capable of creating images 200 metres wide at high resolution even in shallow water environments, all while consuming very little power. The Solstice family of sonars are built on unique MAS technology and are designed to fill the gap between standard side scan sonars, which are typically simple in design but give low image resolution, and Synthetic Aperture Sonars (SAS), which are expensive, more susceptible to complete data loss due to platform movement and also produce vast amounts of data. In order to execute more detailed mapping, Solstice MAS requires a high quality navigation sensor, which in this case is SPRINT-Nav Mini.

SPRINT-Nav Mini is an all-in-one vehicle guidance and navigation instrument, which combines AHRS data, Doppler Velocity Logger (DVL), Inertial Navigation System (INS) and depth sensor into a single housing. Having SPRINT-Nav Mini fitted onto the ROV provides positioning input, as well as attitude and heading data.

Adopting these technologies on such small versatile platforms opens the possibility of high-grade survey data in shallow waters. As a result of the cross Covelya Group collaboration between Sonardyne and Wavefront Systems, a high-definition map of seagrass beds can be created with a greater degree of accuracy than was previously possible with more traditional methods.

A seagrass restoration project conducted by the Ocean Conservation Trust (OCT) in Plymouth Sound, which involves monitoring, conserving and expanding the existing seagrass beds can be enhanced with the use of an ROV which has SPRINT-Nav Mini fitted to it. To help grow the existing seagrass beds, the OCT are placing seagrass mats on the seabed in Plymouth Sound. A survey boat fitted with Solstice and SPRINT-Nav Mini followed by an ROV fitted with SPRINT-Nav Mini can then be used to monitor and create a map of where these mats have been placed so that they have a better understanding of the success of the restoration and expansion project.

Repeatable, configurable, long-term surveillance

The Autonomous Monitoring Transponder (AMT) is a long-endurance transponder engineered for your long term subsea survey tasks and is capable of autonomously acquiring acoustic ranges and sensor data without surface control.

AMTs can detect subtle movement often not picked up by traditional ROV surveys so it’s ideal for monitoring slow movements, like creeping or buckling pipelines. Using structure and seafloor transponder buckets, they can be ROV-deployed, removed and re-installed to provide insight over time. Your AMTs can be configured to take measurements at specific intervals and be adjusted on-demand by you as your campaign progresses. Data can even be collected in real time using a USV should your operation need it.

As it’s collected, data is time-stamped and logged internally for recovery via the integrated high-speed acoustic telemetry modem. This autonomy allows measurements to be made over a long period of time without requiring a surface vessel or ROV to command the process. This enables new applications that save vessel and survey time so reducing cost and risk.

At a glance

• Recommended for long endurance site surveys
• Leave it deployed for six years or more
• Extensive choice of monitoring sensors
• Depth rated to 3,000 m
• Harvest data using a ship, buoy, AUV or USV

AMT has many of the same acoustic functions as Compatt 6, our most popular navigation transponder. It operates in the Medium Frequency (MF) band and is fully Sonardyne Wideband 2 compatible.

Precision pressure, temperature, sound velocity and dual-axis inclinometer sensors are integrated and are intelligently powered up at the requested time and sampling period, providing an ultra-low power platform for up to three years deployment. Sampling regimes can be re-programmed, and recovery of all data can be achieved via the acoustic modem.

The instrument is available with a range of omni and directional transducers, depth ratings and pressure housings dependent on deployment duration and application. Additional external sensors can be easily integrated via the power and communications port.

What's possible

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

Part of our range of acoustic releases, RT 6-3000 combines our extensive mechanical design track record and many years of subsea mooring experience with the flexibility of our 6G platform. The result is an enhanced battery life and, perhaps most significantly, compatibility with our Ranger 2 USBL family.

Deploy. Track. Locate. Recover.

With RT 6-3000, you can use 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 configure and command your RT 6-3000s.

RT 6-3000s are 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 are achievable.

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 don’t have to open the unit to manually disconnect the battery, saving time and reducing the risk of incorrect re-assembly.

Standard features include a Working Load Limit (WLL) of 1,275 kg (at 4:1) and the same trusted spring-assisted release mechanism used on thousands of Sonardyne transponders globally for many years. 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.

Entry level – next level

What's possible

The RT 6-1000 is the versatile acoustic release transponder for your subsea operations. It can be commanded from multiple sources, including the Deck Topside, an Android app, or any Ranger 2 USBL system. This flexibility allows you to easily deploy, track, locate and retrieve your seabed equipment and ocean sensors.

One of the key advantages of the RT 6-1000 is its depth rating of 1,000 metres and weight load limit of 150 kg. This depth and payload capacity make it an ideal choice for scientists, surveyors, and military personnel who require a reliable and enduring solution for their underwater applications.

The RT 6-1000 is compatible with Sonardyne’s Ranger 2 USBL tracking systems, which are widely used on survey vessels around the world. This integration allows for seamless deployment, tracking, and retrieval of your equipment. No access to Ranger 2? No problem, the RT 6-1000’s NFC capability enables setup and control via its Android app or a dedicated Deck Topside unit.

Deploy. Track. Locate. Recover

At a glance

• The reliable choice to deploy, leave and recover seafloor equipment and sensors
• 1,000 metre depth rating; twice that of similar low-cost acoustic release transponders
• Tested, loaded, commanded and released using Deck Topside
• Also works with any Ranger 2 USBL to track it and activate it
• >13-month battery life means less time servicing it and more time using it
• 150 kg Working Load Limit to support your sensors and instruments
• Optional rope canister for heavy lifting

The RT 6-1000 offers impressive endurance, with a battery life of up to 13 months, making it well-suited for long-term deployments and year-long surveys. Its screw-off release mechanism ensures reliable recovery of the transponder and your equipment.

An optional rope canister attachment allows you to quickly and easily raise items left on the seabed, such as tools, cables and salvage. The canister deploys a high-strength rope as the transponder ascends, providing a convenient means of retrieval.

Unlocking subsea secrets with PIES

Imagine the possibilities

Boost your operations: Make informed decisions with a deeper understanding of ocean currents and seismic activity.

Save time and money: Deploy PIES for up to five years, reduce personnel costs and environmental impact through unmanned data retrieval.

Uncover hidden insights: Combine PIES data with other geophysical measurements for a comprehensive view of the ocean floor.

How PIES works for you

PIES is designed to seamlessly integrate into your system:

• Easy to use: Simple setup and configuration, with flexible ping rates to match your needs.
• Reliable data: Consistent, accurate measurements for months or even years.
• Versatile retrieval: Access data when you want it, remotely, mid-operation, via unmanned vehicles or by traditional end of mission retrieval methods.
• Comprehensive insights: Developed for marine seismic and ocean science applications.

Why invest in PIES

• Suitable for environmental surveys / ocean currents monitoring / site survey and characterisation
• Harvest data using ROV, AUV, USV or surface vessel
• Integrated acoustic release for easy recovery
• Depth ratings to 6,000 m
• Choice of form factor to suit your operations

Overview

Acoustic release transponders are a vital piece 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 6-6000 meets these requirements.

Part of our new range of acoustic releases, RT 6-6000 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 6-6000, you can use your vessel’s 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 6-6000s.

At a glance

• Tested, loaded, deployed and released using Deck Topside
• Also works with Sonardyne Ranger 2 USBL to deploy, track and command in very deep water
• Highly reliable release mechanism design and thousands are in service globally
• Working Load Limit 1,275 kg (4:1)
• Depth rated to 6,000 m
• External battery disconnect to maximise battery life with no need to open unit
• Compact and rugged design

RT 6-6000s 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.

Standard features include a Working Load Limit of 1,275 kg (at 4:1) and a spring-assisted release mechanism. RT 6-6000 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 6-6000s use the same trusted spring-assisted release mechanism that has been in service for many years and used on thousands of Sonardyne transponders globally.

Overview

The instrument is a turn-key solution comprised of carefully selected high grade and highly reliable inertial sensors integrated into in-house designed inertial measurement unit (IMU).

The selected inertial sensors are the standard for commercial aviation with a proven 20+ year track record. These sensors have a highly desirable characteristic being insensitive to vibration, temperature changes and having very limited initial errors. The result is a system which is highly suitable for the marine environment where performance, robustness and data integrity need to be available from initialisation, even during the harshest conditions.

Lodestar requires no external aiding and settles robustly in dynamic conditions in less than five minutes. On-board data storage and backup battery functionality ensures continued operation and eliminates the risk of data loss even if communications or external power are lost. Power-pass through to external aiding sensors is supported to ease integration requiring only a single cable for comms and power.

If a full INS solution is required, Lodestar can easily be field upgraded to a SPRINT system (apart from Lodestar 200). This makes the Lodestar a flexible and future-proof solution for both ROV guidance and survey applications.

Lodestar has a proven track record spanning more than 10 years in the field in diverse applications from ROV guidance and autopilot to demanding survey applications. The instrument is available in 4,000 and 6,000 metre depth ratings with a variety of connector options and configurations.

At a glance

• Designed to aid subsea vehicle guidance: AUVs, ROVs and UUVs
• Uses high quality Honeywell gyro and accelerometers
• Sensors available in three performance levels: 200, 300 and 500
• Fast settling time so you can get straight to work
• Integrated DVL option available; Lodestar-Nav
• Factory upgradeable to SPRINT INS

Lodestar-Nav 200
Lodestar-Nav 200 provides all-in-one navigation solution for subsea vehicles by combining a Lodestar 200 AHRS with our Syrinx Doppler Velocity Log (DVL) and a high accuracy pressure sensor in a single housing.  This saves cost, payload space and the complexity of integrating and operating separate sensors from different vendors.

Lodestar-Nav is pre-calibrated providing the ROV pilots with a robust and reliable solution, even in the most challenging operational scenarios, without needing to worry about sensor offsets.

Syrinx DVL inside that provides a large altitude range and high precision at all altitudes; this combines the best of 300 and 1200 kHz DVLs. Each DVL transducer is fitted with a full depth rated water block to ensure protection of the internal components and easy replacement if damaged.

Lodestar-Nav can be interfaced via a single connection and/or the DVL can be interfaced separately depending on requirements. Continuous on-board data storage supports post-mission diagnostics and post-processing.