Fast Attack: Still a Threat in the Littoral

This is an article published in our April/May 2018 Issue.

The US Navy Mark VI Patrol Boat, by SafeBoats, has a 45+ knot speed, crew of ten and can accommodate eight passengers. It’s primary armament is two Mk 38 Mod 2 RWS 25 mm chain guns. It may also mount the MK50 .50 caliber Gun Weapon System (GWS) and plans are to possibility add Raytheon’s BGM-176B Griffin a lightweight, precision-guided missile.

Small, swift missile-bearing attack craft can do great damage at range if allowed to do so.

Fast craft have received a great deal of attention since their well publicised use by the Iranian Revolutionary Guards in the Persian Gulf. Their wide naval use, however, goes back at least to the 1870s with development of the self-propelled torpedo. Today the missile boat has largely, but not totally, replaced the torpedo boat but these and other fast craft continue to fill a range of roles. Although the level of emphasis and numbers and types of boats differ in various navies, they remain an important asset.

Fast Combatant Craft Torpedoes to Missiles

The first true surface attack fast craft was the motor torpedo boat (MTB). These combined sleek hulls with large engines providing fast and agile boats that could attack larger ships using this new weapon. The idea was that a number of boats would attack together. They would move in as close as possible without being detected and then use their speed to quickly move into firing range, launch their torpedoes and turn away allowing the torpedoes to travel to their intended targets. The torpedo boats were viewed with great concern by the major naval powers with large capital ships. They responded by developing and install rapid firing naval guns on existing combatants, as well as, the design and launching of an entirely new ship class, the destroyer (originally called torpedo boat destroyers).

The Patrol Torpedo Boat of World War II had speeds of up to 37 kts (68.5 km/h) and carried two to four torpedoes plus .50 machineguns and later 20mm and 40 mm cannon. PT 658 (shown) was restored by private efforts and is in Portland Oregon.

Many navies then, as today, saw these fast boats as an inexpensive counter to major capital warships. However, despite their wide spread use in World War II and some successes they did not fully meet combat expectations in the attack role for which they were originally promoted. Most were retired or assigned patrol duties. The development of the anti-ship missile in the 1950 renewed interest in the fast craft replacing the torpedo with missiles that could be launched 50km and more from a target. Improvements have increased flight speeds to supersonic and ranges around 1000km are possible, although most are below 300km.

The fast missile boat remains popular with navy’s that have more confined waters and broad littorals to defend. This is represented by the Peoples Liberation Navy of China’s commitment to such craft with over 109 in service. These include the Type 22 (Houbei class) a catamaran design launched in 2004 using water jet propulsion that reaches speeds of 36 knots (66km/h). It has eight C-801/802/803 anti-ship missiles plus a 30mm AK-630 rotary cannon. The C-803 has a range over 350km and an active homing seeker. The craft’s lines and construction seek to reduce its radar and other sensor signatures. The primary role of the 30mm gun is defence against attacking aircraft and incoming missiles.

The Peoples Republic of China has made a major investment in fast missile boats. Its Type 22 Houbei class Missile Boat, here firing aYJ-83 SSM, seeks to combine speed of a catamaran hull with low-detectability using smooth lines in the superstructure.

Today speed, missile range and also stealth are keys to the fast missile craft’s ability to succeed. Avoiding detection or at least reducing detection time is critical. Boats seek to launch their missiles before being engaged. The goal of the force being attacked is to detect and destroy the boats before they fire. Considering the ranges of anti-ship missiles, this becomes the job of surface or airborne surveillance. Therefore, there is increasing emphasis on stealth in the latest fast craft designs. Even then the common employment remains committing many boats to attack in concert firing salvos of missiles so as to overwhelm the enemy – much the same tactic as used by torpedo boats.

The fast attack/ missile boat lends itself to use by smaller navies for protecting coastal waters. Here a Polish Navy Orkan fast missile attack craft with SAAB’s RBS-15 MkIII missiles with 200+ km range and both ship and land attack capability. The craft has a top speed of 39 kts (72 kmh) and also mounts a 76mm naval gun.

The design goals of Umoe Mandal AB, developer and manufacturer of Norway’s Skjold-class, were that ‘although high speed is important, achieving stealth is critical to craft survival and mission success’. Its 274 tonne Skjold air-cushioned surface effects catamaran hull at 60 knots (111km/h) is not only the fast but achieves the lowest possible radar and thermal signature. An executive explained that ‘not only are the lines configured to reduce radar returns but radar absorbing materials (RAM) are incorporated into the structure itself”. It carry’s eight Kongsberg Nye Sjoemaals Missiler (NSM) anti-ship missiles, an Oto-Melara 76mm rapid fire cannon, and MBDA Mistral twin launcher infrared seeker short-range surface-to-air missile.

Past combat actions by missile boats have suggested several lessons learned. First, counter-measures like ECM, chaff and decoys can be very effective in spoiling a missile attack. This applies to the missile boats themselves as well. Second, an effective on-board air defence capability can at least complicate air attack against boats. This was demonstrated in the Iran-Iraq war when an Iranian Combattante II-class Missile Boat not only survived an attack by four MIG-23s but shot two down. Another point is that combat results suggest that multiple missile hits are required to fully take a ship out of action; therefore, a number of missiles must be launched at each target.

The Iranian Revolutionary Guards have embraced the fast attack craft as a means to challenge control of local waters in the Persian Gulf. However, boats like this small craft with a forward 12.7mm machine gun are credible only against unarmed, or unprepared opponents.

These requirements, as well as the desire to enhance cruising range and endurance needed for blue water missions has seen missile boat sizes increase. The Corvette designation is becoming increasingly applied to these new designs. Corvette sized vessels of 500 to 1000 tonnes allow outfitting with more diverse combat, weapons and defensive suites. In addition, the versatility of the craft is enhanced including countering opposing fast craft when appropriately equipped with anti-ship missiles, rapid fire gun, surveillance and targeting systems, and possibly a helicopter landing pad. Builders have demonstrated that despite the increased displacement these vessels are capable of high speeds of well over 35-40 knots (65-74km/h).

Finland’s Hamina-class, although only 250 tonnes, reflects this. In addition to its superstructure made of reinforced carbon fibre composite the shape and materials that reduce the ship’s magnetic, heat and radar signatures. It has an armament suite of 100km range RBS-15 missiles, a Bofors 57mm cannon, and Umkhonto-IR surface-to-air missile system capable of engaging multiple aircraft at up to 14km. This is complemented by Rheinmetall’s multi-ammunition soft-kill system (MASS) with Philax chaff and infrared flare decoys, an Etienne Lacroix anti-threat optronic screening (ATOS) system and a MEL Matilda radar intercept ECM.

Finland’s Hamina-class is constructed with an aluminum hull and re-enforced carbon fiber composite superstructure provided a lightweight vessel that can carry a substantial combat capability including Bofors 57 mm/70 SAK Mk3, four Saab RBS-15 Mk2 SSM, Denel Umkhonto-IR SAM (Denel) plus a full ECM/ESM defensive suite.

Sweden’s Visby-Class designed by Swedish Defence Materiel Administration (FMV) and built by Kockums AB is another combination of speed and stealth in a larger (640 tonne) platform. Saab’s design minimises the vessels transmitted and reflected energies – heat, light, sound, electric potential, and electromagnetic radiation to deny an opponent the opportunity to locate, identify, track, and attack it. These properties and speed and agility are seen as critical to the multiple missions the Visby is designed to perform. To this end Visby uses combined diesel or gas (CODOG) turbine arrangement for high speeds and two diesel engines for low-speed driving two water jet propulsors. The propulsion system provides a continues maximum speed of 15 knots in Diesel engine mode and 35+ knots (65 kmph) in Gasturbine mode. This arrangement is also addresses an operational limitations of many fast craft – that of having limited range and endurance. Visby can travel up to 2500nm (4600km).

The Visby Class Corvette design emphasis is on stealth and minimizing its signatures. Even the forward gun mount is configured to the end. Here seen at speed in the Baltic on NATO exercises in 2017.

Fast Attack Craft

The fast attack craft cover small craft ranging from pleasure craft or racing boat designs armed with small arms and portable rockets to purpose built high speed boats. Used in close waters and where cover and concealment can be provided by coastal topography the sortie and withdrawal tactics they use can be effective. In more restricted waters which channel ship passage, like the Straits of Gulf of Hormuz and Malacca or against unexpecting or unprepared ships it can be decisive.

Despite the public attention that they have received these craft as most often encountered to date are not capable of sinking a major ship. The exception to this, as demonstrated in a US war gaming several years ago, is where craft are used in massive suicide attacks. They have short range and are primarily useful controlling local sea space, deterring intrusions, and harassing and challenging shipping operating in home waters. They are capable of hit and run attacks against armed ships but could have much more serious consequences employed against commercial shipping.

Iran’s Navy of the Army of the Guardians of the Islamic Revolution (also referred to as the Revolutionary Guards) have been aggressive in pursuing fast attack craft (FAC). Their reverse engineering of the Ice Marine Bladerunner has assisted them in design and manufacture of the indigenously produced Seraj-1 fast attack craft. Another, the Torgah fast attack craft, is based on the Swedish ‘Boghammar’. They have since expanded to include additional craft, all locally designed and manufactured, with an objective of fitting more powerful weaponry than recoilless guns and heavy machine guns. The Zolfaghar fast attack craft includes twin tubes for Nasr-1 cruise missiles and a 70 knot (130kmph) top speed. Iranian officials claim to have adapted other anti-ship missiles to their FACs as well as the Shkval E a supercavitating 200 kt torpedo with 7500 m range. These could significantly change the threat and appropriate counter actions.

For other Navies, including the US Navy, high speed craft are largely employed for near shore patrol and special operations in littoral and riverine support. The MarkVI PB, built by Safe Boats, is the US Navy’s most recent entering service in 2015. Hartwell Champagne, senior vice president of operations, shared with AMR, “the vessel is designed for optimal performance, fuel economy, and firepower, as well as, reducing Total Ownership Cost (TOC). Its twin diesel engines and water jets, provide speeds in excess 30 knots at full load and 600+nm range.  She has berthing accommodations, galley and facilities for extended missions.” The US models have two remote operated MK-38 Mod2 25mm guns plus mounts for 50-calibre machine guns. Ramta, a division of Israel Aerospace Industries (IAI), has provided its Super Dvora MKIII multi-mission patrol and attack boats to Israel and others. The 27.4m boat has twin water jets for 40+ knots speeds. It mounts a Rafael Typhoon stabilised 25mm cannon, as well as, optional missiles like the 8km range Hellfire with semi active laser homing millimeter wave radar seeker.

The US Navy Mark VI Patrol Boat, by SafeBoats, has a 45+ knot speed, crew of ten and can accommodate eight passengers. It’s primary armament is two Mk 38 Mod 2 RWS 25 mm chain guns. It may also mount the MK50 .50 caliber Gun Weapon System (GWS) and plans are to possibility add Raytheon’s BGM-176B Griffin a lightweight, precision-guided missile.

Singapore, through ST Marine, developed and fields the 25m (82 ft) 45 tonne Specialized Marine Craft (SMC) which has only two meters above water. Its twin 2500hp MTU engines with Hamilton water jets and coupled with a flatter hull form allows tight turn and speeds in excess of 30 knots (56km/h). A stabilized 12.7mm machine gun is mounted forward. The last of eight SMC’s were delivered in 2017.

Unmanned Fast Craft

Advances in remote and autonomous control have allowed successful demonstration of unmanned fast surface craft. “Maritime Tactical Systems (MARTAC) have designed and successfully tested their MANTAS, a low profile, twin hull, Tactical Autonomous Unmanned Surface Vessel (USV) in sizes from 0.9m (3 ft) up to 3.7m (12 ft). Chris Valdez, chief information officer, indicates that larger, currently up to up to 6.1m (20 ft) craft, are already in design and could be available within 9-12 months. He stressed “that although these USV craft offer ‘burst speeds’ of up to 50 knots, it is their exceptional manoeuvrability, stability, and payload capability that most sets them apart from similar sized craft.” China’s People’s Liberation Army (PLA) Daily reported in October 2016 that it too has demonstrated an “intelligent unmanned fast sea vessel” the SeaFly-01. The 10.25m vessel has a maximum speed of 45 knots. Both are currently viewed as sensor platforms but other missions are possible.

Autonomous Unmanned Surface Vessels (USVs) have demonstrated their abilities to navigate and perform reliability as stable, high speed platforms without outside direction. Mantas (shown) by MARTAC is both fast and low signature ideal for discrete surveillance.

Fast Craft How Valuable?

Fast craft have an undoubted advantage in close waters and complex littorals. For them success depends on gaining and maintaining the initiative through surprise and speed of manoeuvre. If this is forfeited they, even in numbers, can be destroyed. Radar detection, particularly airborne surveillance, and air attack including armed helicopters is their most serious threat. Operating without air cover or anti-air protection can be risky or worse. In actual combat action where fast craft attacks were successfully when opposing air power was unavailable or neutralised. The corollary is that any ship or flotilla without through surveillance and a layered defence, including picketed surface combatants, armed helicopters and immediately on-call attack air remain open targets to the fast craft when they are used in favourable circumstances.

by Stephen W. Miller