High speed naval assets

A number of high-speed naval vessels currently in service are capable of speeds between 40 and 70 knots, significantly outpacing most surface combatants. Some high-speed vessels are specialised on performing particular mission profiles, while others are multi-mission craft.

One characteristic that they all share is their relatively small size, with even the largest units being classified only as corvettes. A comparatively recent phenomenon has been the autonomous or semi-autonomous unmanned speed boats which are increasingly being deployed for armed reconnaissance or assault missions. This article examines a selection of in-service and proposed vessels of various categories.

Assault craft

SAAB CB90: One of the best known high-speed vessels is the Saab CB90 fast assault craft. More than 250 units are operated by the Swedish Navy and seven other nations worldwide. Ukraine’s Holovne Upravlinnia Rozvidky (HUR, Directorate of Military Intelligence) became the newest operator in 2024, deploying the boats for reconnaissance and surveillance missions.

The current production variant is designated the CB90 NG (‘next generation’) or, in the Swedish Navy, the Docksta CB90 HSM. The first of 18 ordered units was delivered to the Swedish Navy in October 2019, where they are expected to serve beyond 2040. The CB90 NG is equipped with a new driveline and engine placement, optimising the boat’s centre of gravity for increased stability and quieter operation. It also features new waterjets that contribute to its higher efficiency and speed. Saab cites a top speed of over 40 knots at maximum load, leading some observers to postulate a speed of around 45 knots with a lighter load. The combination of low silhouette, high speed and agility optimise the CB90 for covert approach. For assault or insertion missions the boat can drive up onto unprepared beaches or extend a ramp onto rocky coastlines to land or retrieve up to 18 fully equipped soldiers.

Weapon options to date include up to three large calibre machine guns and one Mk 19 grenade launcher, as well as naval mines and depth charges. The CB90 NG can also accommodate smaller missile systems including the Hellfire. The Swedish Navy also plans to add mortars, air-defence missiles and guns, and a new anti-ship missile (ASM) to be designated RBS 18 to the boat’s modular arsenal.

‘Jehu’ class: The Finnish Navy acquired the first of 12 U-700 ‘Jehu’ class assault craft in June 2015. The 20 metre long, 32 tonne boats are based on Marine Alutech’s M18 Armoured Modular Craft (AMC). They serve as assault transports or combat support vessels, perform casualty evacuation missions, and conduct littoral surveillance patrols. The U-700 can transport 24 combat equipped soldiers in addition to its crew.  Two 900 hp Scania DI 16 007 Diesel engines and two Rolls-Royce (now Kongsberg) 40A3 water jets, combined with a 1.1 metre draught, make the boats highly manoeuvrable in shallow coastal or archipelagic waters, and provide the boats with a sprint capability in excess of 40 knots. A stabilised ‘Trackfire’ remote weapon station (RWS) has equipment options that include 12.7 mm or 7.62 mm machine guns and a 40 mm automatic grenade launcher. It is augmented by hard points for two additional 12.7 mm weapons. The aluminium hull and composite superstructure offer ballistic protection, as well as resistance to chemical, biological, radiological and nuclear (CBRN) threats.

In 2022 Lithuania announced its intent to purchase two ‘Jehu’ class units for surveillance and security missions in the Curonian Lagoon. Deliveries are expected in 2025.

Coastal/littoral patrol and defence

Skjold class: The Royal Norwegian Navy’s 47.5 metre, 274 tonne Skjold class coastal defence corvette displays a strong combination of speed and firepower. Its cruising speed of 40 knots exceeds the maximum speed of most warships, while a 60 knot sprint speed facilitates interception of hostile or suspect vessels. Its arsenal includes a 76 mm Oto Super Rapid deck gun and eight Kongsberg Naval Strike Missiles (NSMs). The latter have a range in excess of 100 NM and are carried internally to preserve stealth. Man-portable Mistral air defence missiles and 12.7 mm machine guns provide additional defensive capabilities.

Developed in the 1990s by Umoe Mandal and entering operational service from 2010, the six active units are currently undergoing a service-life extension programme (SLEP) focussed on installation of new sensors and combat systems. Umoe Mandal and Kongsberg are collaborating on the SLEP under contracts awarded in 2022. Sensor upgrades include introduction of the Scanter 6000 radars with an all-weather capability to track small targets. According to Kongsberg, the combat system upgrades consist primarily of a new combat management system based on that installed in the Fridtjof Nansen class frigates, as well as improved tactical data link capabilities.

K5 Kraken: The K5 Kraken gunship – which is currently being developed by UK-based Kraken Technology Group – is also intended to combine speed and combat power, albeit in a much smaller footprint than the corvette-sized Skjolds. According to Kraken, the K5 has been designed from the keel up as a fully integrated weapons platform for littoral environments, utilising input from former British and US Special Operations personnel. Its powertrain will consist of twin inboard Diesel engines with surface drives, enabling a fully-laden top speed of 65 knots. Alternatively, a cruising speed of 50 knots will permit a 400 NM operating range that can be further increased through extended-range fuel tanks. The 15 metre boat will also be heavily armed for its size. Its proposed arsenal includes two 7.62 mm mini-guns, a roof-mounted Seahawk compact weapon station with a 30 mm automatic cannon, four Thales Lightweight Multi-role Missiles, four aft-launched Leonardo Black Scorpion mini-torpedoes, and tube-launched UAVs/loitering missiles. An interchangeable aft deck will be able to accommodate various payloads up to 1,500 kg that could include unmanned surface or underwater vehicles.

The K5’s mission spectrum includes strike missions against coastal or offshore targets, interdiction and engagement of surface vessels, and defence of offshore and coastal infrastructure or harbours. The gunships will also be able to be carried and launched at sea by large surface vessels equipped with a stern ramp or dock. This permits the K5 to provide force security for surface ships and expeditionary task groups in littoral waters and chokepoints; intercepting fast attack craft, manned or unmanned boat swarms, subsurface and aerial threats.  The K5 will have a four-person crew and be able to operate independently or as part of a swarm.

Special Operations vessels

The US Navy’s Special Operations forces currently operate several fast boat types. These include the Combatant Craft Assault (CC-A), Combatant Craft Medium (CC-M), and Combatant Craft Heavy (CC-H). Whilst many aspects of these streamlined vessels remain classified, the military and the builders have released some important details. Their size and performance parameters vary but all three types are optimised for high-speeds, manoeuvrability, and suitability for both open water and shallow water operations. They conduct a variety of missions including covert transport and support of Special Operations personnel; reconnaissance, surveillance and intelligence missions; counter-terrorism; fire support; and armed interdiction. They are suitable for medium-to-high threat environments. All can operate from ships with a well-deck, while the CC-A can also be airdropped into an operating zone via a C-17 transport aircraft.

Combatant Craft Assault: The smallest of these vessels, the 12.5 metre mono-hull CC-A, achieved full operating capability in 2017 with a full complement of 32 units. The boats continue to be built by United States Marine, Inc. (USMI) under a 2020 contract to replace older units with upgraded versions. Sensors include a mast-mounted surface search radar and a Combatant Craft Forward Looking Infrared II (CCFLIR II) system incorporating infrared, day and low light video cameras as well as a laser range finder and pointer. It carries a crew of four plus eight operators. Civilian sources dealing with Special Operations widely report that the CC-A has a top speed around 52 knots. While that speed has not been confirmed officially, the CC-A exhibits many design similarities with the 13 metre High Speed Interceptor Craft (HSIC) that is also produced by USMI. The HSIC is powered by twin Cummins QSC 8.3 marine diesel engines with outdrives and is credited with a top speed of over 55 knots by its builder. It incorporates a deep-vee mono-hull that is constructed from high-tech composites and provides and offers shock mitigating seating for its 12 occupants.

Combatant Craft Medium: The 18.5 metre CC-M was designed and constructed by Oregon-based Vigor Industrial LLC. US Special Operations Command (SOCOM) operates a total of 31 of the craft. The boat can accommodate 19 operators plus its four person crew. A CCFLIR II is mounted atop the cabin. The rear deck is sized to accommodate a Combat Rubber Raiding Craft (CRRC) whilst installation of a universal launch and recovery system for future payloads is planned. Two medium or heavy machine guns can be mounted at the aft corners of the deck. SOCOM has confirmed plans to add precision strike loitering munitions. An eight round pop-up launcher, which appears to retract flush into the deck when not in use, is currently being evaluated on one operational CC-M. According to US Navy Commander Marty Burns, surface systems program manager at SOCOM, testing should conclude by early Fiscal Year 2025 and will be followed by a decision regarding installation across the CC-M fleet.  The CC-Ms are equipped with two MTU 8V2000 M94, 1,250 hp engines. Vigor confirms a top speed of 52 knots and a cruise speed of 40 knots, with an operating range of 600 NM.

Combatant Craft Heavy: The 25 metre CC-H is also known as the SEALION (SEAL Insertion, Observation and Neutralization). The low-profile, spearhead-shaped boats are the stealthiest members of the combatant craft family; they are capable of semi-submersion to avoid detection during surveillance missions. In addition, their sensors and weapons are retractable to minimise the radar signature. The first three CC-Hs were designed and built by Vigor; two of these were originally built as demonstrators but subsequently accepted as operational craft in 2014. The third unit, which entered service in 2021, was the first purpose built operational craft. The US Navy contracted a fourth vessel from Fincantieri in April 2024 and there is an option for a fifth unit that SOCOM seems determined to exercise. The Pentagon’s FY 2025 budget request cites a 40 knot speed and a 400 NM range, as well as a capacity for 12 passengers and a seven person crew. Non-official sources frequently cite higher sprint speeds and range. While these cannot be verified, it would be logical to assume that the US military is publicly downplaying capabilities to mislead adversaries.

High speed naval transports

Expeditionary Fast Transport: Catamaran hulls are particularly suited for high speed transport vessels such as the Spearhead class (T-EPF-1) Expeditionary Fast Transport units built by Austal USA for the US Navy. According to Austal, the 103 metre long vessels can achieve 43 knots speed without a payload, or 40 knots fully loaded. They have a 1,200 NM range at a 35 knot cruising speed.

The class’s fifteenth unit, USNS Point Loma (EPF-15) was christened in August 2024. This vessel is the second unit being built to the EPF Flight II configuration, which is equipped with enhanced medical facilities that include primary surgery, an intensive care unit, ward beds, and limited diagnostic facilities. The catamaran’s inherent stability permits surgery to be conducted while underway.

The 13 Flight I EPF vessels (originally designated as the Joint High Speed Transport) are configured for rapid delivery of personnel, supplies or vehicles. Airline style seating for 312 troops and berthing for 104 troops is provided (in addition to accommodation for the 41 person crew). Additionally the mission deck provides more than 1,800 m² space for palettes, ISO containers or vehicles up to the size of main battle tanks. Complete company-level units can be quickly relocated together with their equipment in one sortie, and debark combat ready. Alternately the mission deck can be used as a mission support platform for mine countermeasures, unmanned systems operations, or special operations forces.

Ghostworks M90: At a smaller scale, the developmental, 28 metre long Ghostworks M90 offers similar versatility. Developed by the relatively new (2022) Michigan-based Ghostworks Marine, the design incorporates a so-called ‘M-Hull’ configuration to provide enhanced stability at all sea states. Depending on configuration, the vessel will be able to achieve 50 to 55 knot speeds, with a 700 to 900 NM range carrying payloads of up to 35 tonnes. In addition to acting as a fast transport, the M90 will also be able to function as a mothership/support ship. A multi-purpose reconfigurable launch bay can accommodate 11 metre RHIBS, as well as small uncrewed systems. A basic three to five person crew can be augmented by up to 15 mission specialists, with three-day endurance at sea.

The unmanned future

MARTAC Devil Ray T38: In recent years, high speed unmanned surface vessels (USVs) have been subjected to ongoing tests of their suitability as surveillance and reconnaissance assets. Moreover, attention is now turning to the utility of armed patrol and interceptor USVs. Among the highest performers is the 11 metre long MARTAC Devil Ray T38. The USV is developed by Maritime Tactical Systems of Florida, which cites a burst speed capability ranging between 70 and 100 knots dependent on powertrain option and payload. The craft’s fastest documented run took place in July 2021, when the T38 transited the Florida Straits from Palm Beach to the Bahamas in only 53 minutes. The average cruise speed was clocked at 61 knots, with a fast segment recorded at 71.5 knots. The round trip transit was conducted under full autonomy, with an average tracking accuracy of +/- 1.3 degrees and a steady state cross track error of +/-3 m, all the while avoiding shipping traffic.

The Devil Ray’s payload capacity of 1,800 kg provides for a variety of sensor and weapon options. Operational scenarios include unarmed or armed surveillance and reconnaissance, electronic warfare and signals intelligence, interdiction of hostile or suspect vessels, and armed force protection missions for coastal, offshore, or floating assets. For the latter scenario, the T38 can be carried aboard larger ships and deployed via well deck or winch to escort ships through chokepoints or littoral waters. The armed T38 can operate singly or in swarms, autonomously or under remote control, to intercept fast attack craft and boat swarms well in advance of the protected ship or asset.

The US Navy has included the T38 in its extensive testing of unmanned systems as part of Task Force 59 in the Central Command area of responsibility and, subsequently, in other regions. The Devil Ray can be equipped with the Kongsberg Protector RWS and armed with machine guns or grenade weapons. As part of the TF 59 evaluation, the T38 also demonstrated the capacity to deploy with an aft-mounted Lethal Miniature Aerial Missile System, firing Switchblade 300 loitering missiles. This was credited with destroying multiple surface targets during an October 2023 test in the Persian Gulf.

Magura V5 – and Beyond: High-speed USVs are also being developed to serve as a form of loitering munition in their own right. The Ukrainian company SpecialTechnoExport (STE) has developed the Magura (Maritime Autonomous Guard Unmanned Robotic Apparatus) V5 as a multi-mission USV that has become best known for its successful attack runs against Russian ships. The 5.5 metre long, highly manoeuvrable Magura operates in fully autonomous mode for many missions, following waypoints and avoiding obstacles by using advanced algorithms. With extended endurance capabilities, the V5 can remain on station for extended periods to await targets. On the other hand, the USV’s 450 NM range permits dedicated attack runs against distant targets. In these scenarios, a human operator assumes control via satellite link for the final mission phase, using drone-mounted video systems to guide targeting. Mounted on jet skis, the USV achieves attack speeds of 42 knots. Operated by Ukraine’s HUR, V5 drones – usually operating as swarms – have sunk at least five Russian warships with their 250 kg explosive payloads.

As secure wireless control technology and artificial intelligence progress, direct action offensive operations by USVs will become more commonplace. High speed, agile platforms will be the logical choice for such missions. The Ukraine War and Kiev’s pioneering deployment of technology such as the Magura V5 can be seen as a pivotal point in this course of development.

Sidney E. Dean