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.


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.

  • Last of the RN conventional survey ships. HMS Roebuck – Just outside Umm Qasr, on the Az Zubayr river (Iraq war, March 2003). Roebuck was originally due to be replaced by HMS Echo but it was decided to extend her time in service until 2014. In the event, she was sold to Bangladesh in 2010 as the MoD searched for savings to fund the war in Afghanistan.

  • The RN built four Coastal Survey Vessels (CSV) all completed in 1968 and intended to work together in pairs. They were large enough to be deployed overseas but spent most of the careers surveying around the UK. They cannot be considered the direct forebears of the much larger ocean survey Echo-class, although HMS Roebuck, commissioned in 1986, was based on their design. Seen here HMS Fox and HMS Fawn heading out of Plymouth Sound, July 1981.  (Photo: ©Kieth Miller)

  • HMS Beagle

    The RN re-painted its survey vessels from white to grey in 1997 and also merged the Hydrographic and Meteorology branches to form the HM cadre. HMS Bulldog is seen here flying her paying off pennant as she enters Devonport for the final time, July 2001.

  • HMS Beagle was the last of the original 4 ships in service and decommissioned in February 2002. She was sold and largely re-built as a luxury yacht, MV Titan. She is still in service as a luxury cruise expedition ship in Indonesia, renamed Aqua Blu.

  • The Canadian VARD Marine 9 105 ‘research vessel’ concept was the basis of the design for the Echo class but was substantially revised for RN requirements. HMS Echo and Enterprise will soon have a younger half-sister – in November 2018 the first steel was cut for a South African Navy survey ship, closely based on this design. The South African vessel will have conventional propellers and includes a flight deck and hangar.

  • The VARD 9 105 design featured a flight deck and hangar but the RN decided this was not required. Instead, the foredeck was extended to create a vertical replenishment (VERTREP) deck where helicopters can drop stores without landing. The deletion of the hangar also reduced topweight and allows for a more spacious quarterdeck area for surveying equipment and TEU containers.

  • Artists impression issued by Vosper Thornycroft in 2000. A reasonably accurate representation, although most of the portholes, a hangover from the VARD design were deleted and the funnel exhausts were extended.

  • HMS Echo sails from Appledore for initial sea trails, 10 August 2002 (Photo: © Michael Guegan)

  • HMS Enterprise fitting out at Appledore, 14 May 2003. (Photo: © Michael Guegan)

  • HMS Enterprise first Ship’s Company prior to the formal commissioning ceremony, Devonport 17 October 2003. Present for the photo is the majority of the three watches, only two watches totalling 48 people, crew the ship at any one time. Predecessor HMS Roebuck, a ship of half the size, had a normal complement of 52.


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.


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.)

  • HMS Enterprise has her bottom cleaned while dry-docked in Falmouth 2018. The azipods actually pull the ship forward, the opposite of conventional shaftline propulsion which push the ship forward through thrust blocks.

  • Reverse view of the azipods. No need for rudders, rudderstocks, propeller shafts and shaft brackets.

  • The internal arrangement of the compact Azipod (Image: ABB).

  • Inside the Azipod compartment. The two motors (centre and bottom right) rotate the pod to provide steering for the ship.

  • HMS Enterprise Dry Dock in Falmouth 2013. (Left) She was given a new ‘sealion’ hull coating which is rubbery and smooth, dramatically reducing marine growth, reducing drag. (Right) The Azipods require servicing every 10 years and have been placed in cradles and detached from the hull for maintenance.

  • A young HMS Enterprise carries VIPs as one of the reviewing ships at the Trafalgar Fleet Review, June 2005. Note the original VT Halmatic Survey Motor Boat ‘Pathfinder’ in the after starboard davit.

  • VT Halmatic SMB ‘Nesbitt’ carried aboard HMS Roebuck, Devonport, Aug 2006. Echo and enterprise were originally fitted with this type of boat (SMB ‘Pioneer’ and ‘Pathfinder’) but these were replaced with new boats in 2012. (Photo: ©NavyLookout)

  • Departing CO leaves HMS Enterprise aboard SMB ‘Spitfire’, November 2018. Mustang Marine built 4 of these 10.5m, 9-tonne survey vessels for the RN in 2012. These modern boats allow hydrographers to survey shallow waters with great accuracy and are equipped with a Kongsberg 2040 MBES, EA400 SBES and a 2094 Side Scan Sonar.

  • Launching HMS Echo’s SMB ‘Sapphire’ (Mediterranean, July 2018) Stong, purpose-built davits are needed to safely lift the 9-tonne craft in and out of the water.

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 ships are armed with two Oerlikon 20mm/85 KAA cannons. The gunner is strapped into the GAM-BO1 mounting and manually aims and trains the weapon. These guns have been in service with the RN since the mid-1980s and are basic but adequate for maritime security work. They are supplemented by 3 miniguns and 4 GPMGs for force protection duties.

  • Launching the SeaSoar Undulating Oceanographic Recorder (UOR) using the hydraulic A-Frame mounted on the stern. The UOR is towed behind the ship at up to 10 knots and carries a variety of sensors to measure environmental data in the top 200m of water. The ‘wings’ enable the shuttle to undulate up and down through the water and the propellor generates the power supply for the unit.

  • HMS Echo launched a CTD (conductivity, temperature and depth) probe into the southern Indian Ocean during the search for the missing Malaysian airliner MH370, April 2014. The ‘Baltic room’ on the forward starboard side of the ship has a hatch and an extending crane that allows sensor payloads to be lowered over the side.

  • Hydrographer at work in the office behind the bridge monitoring survey data being collected.

  • HMS Echo Steering Position Bridge. The rotating control levers for the Azipods can be seen left and right with the bow thruster control in the centre.

  • HMS Echo’ spacious Bridge (Photo: ©Moshi Anhory)

  • Main engine control panel in the Machinery Control Room, HMS Echo (Photo: ©Moshi Anhory)

  • Galley, HMS Enterprise

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.

  • In 2013 HMS Echo was deployed on an 18-month surveying mission covering the Mediterranean, Red Sea, Indian Ocean and the Gulf. Seen here in the Gulf, the spacious quarter-deck can be appreciated.

  • HMS Echo’s Survey Motor Boat Sapphire in Tripoli harbour, July 2013 alongside the wreck of the Al Ghardabia – sunk by the RAF during NATO strikes on the forces of Colonel Gaddafi in May 2011.

  • While surveying off Libya in July 2013 HMS Echo located the wreck of Libyan Navy Polnocny-class landing ship Ibn Qis, which was burnt out and sunk in 1978.

  • HMS Enterprise in Antarctica, 2017. She supported British Scientists and provided cover as Falkland Island patrol vessel while HMS Clyde was undergoing refit in South Africa.

  • A secondary role for these ships is to provide logistic support and act as a command ship for mine warfare vessels. HMS Grimsby, Hurworth, Cattistock & Ramsey rafted up with HMS Enterprise during exercise Trident Juncture, Norway, November 2018.

  • HMS Enterprise conducts vertical replenishment practice with Merlin Helicopter during exercise Joint Warrior, Loch Ewe, October 2013.

  • Around 100 British citizens were evacuated from Tripoli by HMS Enterprise in Aug 2014 as fierce fighting erupted in Libya.

  • A rare meeting of the two sister ships – Mediterranean, June 2018.

  • HMS Enterprise Black Sea

    HMS Enterprise rafted up with Romanian minehunters, Feb 2018 as the flagship of Standing NATO Mine Countermeasures Group 2. HMS Echo was also deployed in the Black Sea in December 2018 as a show of support to Ukraine following Russian actions in the Kerch Strait. (Photo: NATO MARCOM)

  • HMS Enterprise off Japan, October 2019. She undertook a lengthy deployment in the Asia-Pacific region 2019-20. Her survey work may contribute to the navigational needs of UK Carrier Strike Group which will probably deploy to the region in 2021.

  • HMS Enterprise arrives from Cyprus into Beirut, 10 Aug 2020 to deliver assistance after the devastating explosion in the city on 4 Aug. Embarked soldiers and Royal Maines delivered a tented accommodation, field kitchens and training for the Lebanese Army. SMB Spitfire was deployed to conduct a bathymetric survey of harbour approaches and the data was handed over to the Lebanese authorities within 24 hours.

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)