In focus: The Royal Navy’s Echo-class survey vessels

HMS Echo and HMS Enterprise are the Royal Navy’s hydrographic oceanographic survey vessels (SVHO). Designed to survey both coastal and ocean waters, they have also proved flexible and adaptable to a variety of other roles. Here we look at the history, design and service life of these two ships.

Background

In 1997 the Royal Navy’s hydrographic ships were repainted from white with buff funnels to ‘Pusser’s grey’ this reflected their increasing integration with warfare and utilisation for missions beyond surveying. Amphibious warfare and, in particular, submarine operations need support with high-definition bathymetry and atmospheric data, sometimes in near real-time and new ships enabled by modern data processing and communications technology would provide this. With ever-decreasing hull numbers, and declining manpower strength, the RN wanted its next-generation survey vessels to have a small crew and designed from the outset for other roles. The ships would need to basic self-defence capability and facilities to act as mine warfare logistic support and command ships as well as perform Humanitarian Aid and Disaster Relief (HADR) missions . While HMS Scott is optimised for specialist oceanography, the SVHOs have a greater all-round capability, designed mainly for hydrographic survey in the littorals and continental shelf.

In the mid-1990s the RN planned to replace its two remaining coastal survey vessels, HMS Bulldog and Beagle, and the newer HMS Roebuck, with three modern vessels that could conduct both ocean and coastal survey work. It was not until June 2000 that it was confirmed that two ships had been ordered from prime contractor, Vosper Thornycroft. The £130 million project included 25 years of through-life support and the construction of both ships which was sub-contracted to Appledore Shipbuilders in North Devon.

The hulls of both ship were constructed side by side in Appledore’s undercover dry dock and the lead ship HMS Echo was floated out into the river on the 2 March 2002, followed a few weeks later by Enterprise on 27 April. Echo was supposed to be completed by August but technical problems at the shipyard and issues with the new azipod propulsion delayed the programme. HMS Enterprise was accepted into service ahead of HMS Echo in September 2003 but her working azipods were removed in Portsmouth. They were donated to Echo in October 2003 so as to speed up her entry into service. HMS Echo formally commissioned on 7 March 2003 but was laid up temporarily in Falmouth awaiting a solution to her propulsion defects. HMS Enterprise was cold-moved to Plymouth, commissioning on 17th October while her crew trained alongside awaiting delivery of new pods.

Pods

Azipod propulsion was pioneered by ABB in Finland and by the late 1990s, the technology had matured to the stage that they were being fitted to a number of merchant vessels. In simple terms, the DC propulsor motor, directly attached to the propellor is hung from a pod below the stern of the ship. The pod is rotated to achieve steering and electrical power to the pod can be supplied from a generator cited anywhere within the vessel. This has many advantages over conventional shaftline propulsion arrangements. The principle benefits are fuel efficiency, vastly increased manoeuvrability, reduced vibration, simplification of machinery layout and elimination of shafts and rudders. Azipods were initially selected for one of the early iterations the Queen Elizabeth Class aircraft designs but later eliminated when they were found not to meet naval shock resistance standards.

Like the Type 45 destroyers, although a less high profile example, the RN took a modest risk by selecting an innovative propulsion solution for the Echo class ships. Unfortunately, the compact Azipods initially fitted to HMS Echo failed. One of their disadvantages is that unlike internal engines, they require expensive dry docking to remove them. ABB eventually paid compensation to the MoD but in the long run, the Integrated Electric Propulsion (IEP) and azipods have proved to be reliable and efficient, ideally suited to the work of the SVHOs.

In combination with the bow thruster, the azipods can rotate the ship on its own axis through 360º. In combination with the ship’s dynamic positioning system (DPS), the ship can maintain a stationary position over a particular spot to facilitate surveying operations such as taking seabed samples. Using the differential GPS fit, the ship can achieve a positional accuracy of 20cm while maintaining 6-8 knots. The azipods also considerably simplify berthing, making them the most manoeuvrable ships in the RN, besides the Sandown class minehunters.

HMS-Echo-General-Arrangement-1

Power generation comes from three MAN B&W 6-cylinder RK270 Diesel-Generators with a total power output of 5.4MW, supplemented by a smaller generator, mainly for use in harbour. The PWM (Pulse Width Modulation)-controlled compact azipods are rated at 1.7MW along with the 0.4MW bow thruster. The ship can be controlled by a joystick, traditional helm or automatically via the DPS and integrated navigation system. The VT integrated platform management system (IPMS) controls and monitors power generation, propulsion and auxiliary plant, tank gauging as well as damage control functions and is accessible through workstations around the ship. There are very high levels of automation with the machinery spaces usually unmanned and generation capacity automatically brought on or offline, depending on the ship’s speed requirement. The SVHOs are not especially fast, with a maximum speed of around 15 knots, but have a good endurance of around 9,300nm at 12knots.

It is notable how much foreign content was included in the construction of these vessels. The Society of Maritime Industries says that typically 70% of the value of a naval ship contract is in the supply chain, while the construction of the ship itself is only around 30%. Based on a Canadian design, the Echo-class incorporate Finish azipods, Danish engines and Norwegian sonar systems. Prime contractor Vosper Thornycroft no longer exists, absorbed by BAE Systems (and their Portsmouth facility was subsequently closed). The Appledore yard where they were built closed in 2018. (But in August 2020 it was announced Appledore has been revived once again with a £7M investment from InfraStrata.)

Core mission

At the heart of the ships is the Integrated Survey System, comprising the Kongsberg Simrad EM1002 Multi-Beam Echo Sounder (MBES) which features a hull-mounted transponder beneath the ship. This is designed for comprehensive and rapid recording of bathymetric and oceanographic data. Additionally, the EM 1002 MBES is optimised for coastal waters down to 1000 meters The EM 3000 MBES is a very high-resolution seabed mapping and inspection system for shallow water. The more basic and EA 400 and EA 500 single beam echo sounders (SBES) are also used to measure depths accurately in shallow waters.

The ship can also deploy off-board sensors from the stern or starboard side. The baltic room has two hydraulic doors that open in the forward starboard side of the ship. A telescopic crane is used to lower payloads over the side of the ship which may include a bottom grab to collect samples from the seabed. To gather accurate data about the water column, sensors such as the conductivity, temperature and depth (CDT) probe, Sound Velocity (SV) Probe or Secchi discs to measure water turbidity (transparency) are lowered vertically. A large hydraulically-raised and lowered A-frame on the quarterdeck is used to deploy instruments towed behind the ship including the undulating oceanographic profiler (UOR) and sidescan sonars. A 2-tonne knuckle boom crane is also used to lift static sensors such as tide gauges out of the water or move survey equipment around the quarterdeck.

The modern survey motor boats, SMB Spitfire (HMS Enterprise) and SMB Sapphire (HMS Echo) are designed to operate independently from the ship for short periods, carrying a small group of surveyors for inshore surveys of beaches, ports and estuaries. They can transmit data directly back to the ship for processing.

Skilled hydrographers working on the Echo class ships, equipped with this wide variety of sensors can collect atmospheric, coastal and bathymetric data which can then be rapidly collated and transmitted ashore, potentially for immediate tactical use. More typically, the data is sent to the UK Hydrographic Office (UKHO) in Taunton for incorporation in globally-respected Admiralty nautical charts or disseminated for scientific use.

The SVHOs were build to Lloyds commercial ship rules and able to operate in a range of extreme climates down to -20ºC. Crew accommodation and recreational areas are comfortable, designed for extended periods at sea. All personnel share a double cabin with bunk beds and en-suite facilities, except the CO and XO who have single cabins. The SVHOs use the same 3-watch system used to crew HMS Scott, Protector and the OPVs. The ships’ company totals 72, comprising 13 officers, 21 senior rates and 38 junior rates divided into 3 watches. Two of thee watches (totalling 48) serve onboard at any one time, working a cycle of 75 days on, 30 days off. This arrangement gives the ships exceptionally high availability, able to remain operational for up to 330 days per year, subject to maintenance requirements. If there is a need to embark additional personnel, there is accommodation for 81 people in total.

Devonport is the home port for the RN’s hydrographic ships but their upkeep is done elsewhere and their constant activity sees them spend little time in Plymouth. Maintenance and refits of SVHOs were formerly done by A&P in Falmouth but in October 2018, UK Docks in Middlesborough was awarded a 10-year £150M maintenance contract for HMS Echo, Enterprise and Protector. HMS Enterprise arrived on Teesside for her first 6-week maintenance period in April 2019, followed by HMS Echo in May 2020. At various times, both ships have also undergone upkeep work while on long overseas deployments at dockyards in Gibraltar, Malta and Singapore.

A varied service history

Since entering service both ships have seen been deployed globally including survey work as far afield as the Indian Ocean, the Persian Gulf, the Black Sea, Antarctica and Norway. Both ships have served with EU Operation Sophia rescuing migrants in the Mediterranean, for which HMS Enterprise was awarded the Firmin Sword of peace. In April HMS Echo was deployed to the waters off Australia to join the, ultimately doomed international search for the missing Malaysia Airlines Flight MH 370. Echo was also employed in an unfamiliar fishery protection role in early 2016. HMS Echo was the first NATO vessel to arrive in the Black Sea in December 2018 after the incident in the Kerch Strait when Russian ships rammed and fired on Ukrainian ships before kidnapping the vessels and their crew. HMS Enterprise had also served in the Black Sea in 2018 as the flagship of Standing NATO Mine Countermeasures Group 2.

In 2019 HMS Enterprise embarked on a lengthy deployment to the Asia Pacific region which included a transit of the Taiwan Strait in December. Having returned to the Mediterranean, she was deployed at very short notice in August 2020 to assist in Beirut in the wake of the devasting explosion at the port. HMS Echo has been in UK waters, mostly operating from Plymouth since completing maintenance in Middlesborough in July 2020.

The average running costs (personnel, fuel and port visits) for these ships is about £5.5M per year. In 2013 the MoD put their Net Book Value (NBV – calculated by adding the cost of upgrades to the original capital cost and deducting depreciation) at about £25M each. It is clear they have provided the taxpayer with exceptional value for money and continue to be an important part of the surface fleet beyond their surveying function.

When originally completed in 2003, the SVHOs were intended to have a working life of about 25 years, so they could expect to be retired in 2028. This is consistent with the 10-year support contract awarded in 2018 but the MoD has not yet published official Out of Service Dates (OSD) for these vessels. With at least eight more years of service ahead of them, there is not the same urgency as a replacement for HMS Scott, but consideration needs to begin soon about how they will be replaced or extended in service.

You can follow the progress of these ships on their lively Twitter accounts @HMS_Echo and @HMSEnterprise

 

(Main image: ©Andy Amor – HMS Echo in the Solent, July 2020)