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Corvettes of the Persian Gulf: A Strategic Survey

Omani Kareer-class Corvette
Omani Khareef-class Corvette

By Paul Pryce

The Persian Gulf has long been a waterway of strategic importance. On average, $105 billion worth of goods are exchanged between Iran and the Gulf states each year. In addition, approximately 20% of the world’s petroleum traverses the Strait of Hormuz, a narrow passage between the Persian Gulf and the open seas. Clearly, ensuring the security of this body of water is vital to the health of the global economy. In this respect, the US Navy’s Fifth Fleet fulfills a significant role, as does Combined Task Force 152, a multinational contingent patrolling the Persian Gulf since 2004. But what role do regional navies play in securing these same waterways?

To address this question, it is worthwhile examining the corvettes employed by the Islamic Republic of Iran, the Republic of Iraq, and the countries of the Gulf Cooperation Council. These smaller, lighter vessels are sufficiently maneuverable to navigate the narrow waterways that characterize the region. Corvettes are also for the most part the heaviest vessels operated by the region’s maritime forces. Comparing the corvettes can provide valuable insight into the current and future balance of naval power in the Persian Gulf.

The Royal Navy of Oman (RNO) is representative of the rapid development taking place in the region’s maritime forces. For several years, the RNO has depended largely on its two Qahir-class corvettes (1,450 tons), which have been in operation since 1996. Beyond this pair of vessels, the RNO operated a single patrol ship, Al-Mubrukah; having begun life as a royal yacht, it was converted to a training ship for a time, then was re-designated to patrol Omani waters in 1997. However, the RNO has commissioned three Khareef-class corvettes (2,660 tons) from BAE Systems, based in Portsmouth, UK. The first of these vessels, Al-Shamikh, was  delivered in October 2013. The remaining two Khareef-class corvettes, Al-Rahmani and Al-Rasikh, are expected in 2014 and 2015 respectively.

The United Arab Emirates Navy also has ambitions to expand its capabilities, though these plans are at an earlier stage. Purchases have been made for six Baynunah-class missile corvettes (915 tons) to replace the country’s six aging Ardhana-class patrol craft (175 tons), which have been in operation since 1976. While one of the new vessels have been completed, the remaining five are not expected for several years due to the relative inexperience of Abu Dhabi Shipbuilding, the local shipbuilder. Even so, the shipbuilder has expressed its hopes to secure further orders of this class for the Kuwaiti and Saudi maritime forces. Aside from the expected Baynunah-class vessels, the UAE’s complement of corvettes is currently comprised of three Abu Dhabi-class corvettes (1,650 tons) and two Muray Jib-class corvettes (630 tons). The former were acquired as recently as 2011, produced by the Italian shipyard Fincantieri. The latter were produced by Germany’s Lürssen in 1990-1991.

The Qatari Navy is currently considering the acquisition of its own corvettes. For the time being, the country has relied primarily on smaller patrol vessels. Its most substantial vessels are four Vita-class fast attack craft (480 tons) and three Combattante III fast attack craft (430 tons). Officials have proposed bolstering the Qatari Navy’s capabilities with the addition of four corvettes, and the favoured option appears to be Damen Schelde Naval Shipbuilding’s Sigma-class corvette (1,690 tons). Several vessels of this design have been in service with the Indonesian Navy and the Royal Moroccan Navy since 2009, with an additional four having recently been purchased by the Vietnamese military. Whether Qatar will follow through with this purchase remains to be seen, but it would certainly enhance the capabilities of the Qatari Navy and the country’s position in the region.

The Kuwaiti Navy and the Royal Bahrain Naval Force are two notable exceptions to the trend of modernization and expansion in the region. The Kuwaiti Naval Force possesses a limited number of vessels, the most substantial of which is a single Al-Estqlaal-class fast attack craft (410 tons) and commissioned in 1983. The remainder of the Kuwaiti fleet consists of nine fast attack craft (250 tons) and various support vessels. There are no plans for Kuwait to acquire a corvette-like vessel in the near future; much of the budget for the Kuwaiti Naval Force has been directed toward the purchase of several landing craft. Meanwhile, Bahrain is experiencing a corvette-sized gap in its fleet. The flagship of the Royal Bahrain Naval Force is an Oliver Perry-class frigate (4,100 tons), which first entered into service with the United States Navy in 1981 and was subsequently transferred to Bahrain as a gift in 1996. Beyond this, Bahrain also operates two Al-Manama class corvettes (630 tons) and four Ahmed Al-Fateh class missile boats (260 tons), all of which were acquired from the German manufacturer Lürssen in the 1980s.

An unknown quality in the region’s maritime affairs is the future of the Royal Saudi Navy. While Saudi Arabia is certainly a leader among the navies of the Gulf Cooperation Council, there are few details available regarding the plans for this country’s maritime forces. There are some indications that Saudi Arabia was offered a package by the United States Navy, consisting of two destroyers and an undisclosed number of Littoral Combat Ships. Whether this package was accepted is unclear. It seems that Lockheed Martin initially offered eight Littoral Combat Ships for the express purpose of joining the Saudi fleet in the Persian Gulf, but again little is known as to how negotiations proceeded – if at all.

The current array of vessels in service with the Royal Saudi Navy, however, is well known. Three Al-Riyadh class frigates (4,700 tons), which are essentially modified La Fayette-class frigates acquired from the French Navy, have been in service since 2002-2003. An additional four Al-Madinah class frigates (2,600 tons) were produced in France but have been in service since 1985-1986. Also aged, four Badr-class corvettes (1,040 tons) have been in service since 1981-1983. While this represents an ample contingent in comparison to the smaller Gulf states, it must also be noted that the Royal Saudi Navy has its forces split between the Red Sea and the Persian Gulf.

The situation of the Iraqi Navy remains rather problematic. While once an impressive force in its own right, the Iraqi Navy was almost entirely destroyed during the Gulf War of 1991. Attempts to acquire four Lupo-class frigates (3,000 tons) and six Assad-class corvettes (675 tons) failed when Iraq became the subject of an international arms embargo shortly before the Gulf War and the completion of the vessels. As such, the Iraqi Navy was not rebuilt and therefore did not play a significant role during the 2003 invasion of Iraq. Presently, the only combat vessels operated by the Iraqi Navy are four Saettia MK4 class off-shore patrol vessels (390 tons). Iraq has especially narrow sea access, limited mostly to the ports of Umm-Qasr and Al-Faw. Accordingly, Iraqi authorities have sought to limit maritime forces to light patrol boats, which are chiefly tasked with patrolling coastal waters and protecting off-shore oil platforms. In short, Iraq is no longer a significant contributor to the security of the Persian Gulf.

In contrast to its troubled neighbour, the Islamic Republic of Iran Navy (IRIN) maintains one of the most substantial fleets in the region and is working to rapidly expand its capabilities. Furthermore, much of IRIN consists of corvettes, though it refers to most of these as destroyers. Three Alvand-class vessels (1,540 tons) are the mainstay of Iran’s presence in the Persian Gulf, though these have been in operation since 1971-1972. The Moudge-class ‘destroyer’ (1,500 tons) is being introduced to serve alongside these older counterparts. One Moudge-class vessel entered service in the Persian Gulf in 2010, while a second entered service in the Caspian Sea in early 2013. Another four vessels of this class are currently being built and delivery is expected soon. Unfortunately, much of the Moudge-class’ capabilities are not publicly available at this time, though it has been noted that the vessels are largely the result of Iranian reverse-engineering of the Alvand-class.

The Sahand-class (2,000 tons), based at least in part on the design of the Moudge-class ‘destroyer’ (and thus the Alvand-class by extension) is also currently under construction. Once again, not much is known of the vessel’s capabilities, but official announcements indicate the vessel currently under construction will be patrolling the Strait of Hormuz and can be equipped with Chinese-designed C-802 anti-ship missiles. Beyond the aforementioned Iranian destroyers, a Bayandor-class patrol frigate (1,135 tons) was launched after a refit in June 2013. An additional Bayandor-class vessel and Hamzeh-class corvette are in operation, though both have been in operation since 1964-1965 and the latter is deployed in the Caspian Sea. Less relevant to the topic of corvettes but still worth noting in any discussion of maritime security in the Persian Gulf, IRIN has accrued a fleet of submarines, missile boats, and minelayers, which could be employed to significantly inhibit traffic through the Strait of Hormuz.

In surveying the corvettes and corvette-like vessels of the Persian Gulf, several regional trends can be identified. Iran has emerged as the most ambitious modernizer, rapidly developing its maritime forces. Some of its newer vessels, namely the Sahand-class frigate, are explicitly intended to exert a stronger Iranian influence in the Strait of Hormuz. Interestingly, the Sahand-class frigate is also named in memory of an earlier Iranian frigate sunk by the US Navy during Operation Praying Mantis in 1988. The Moudge and Sahand-class frigates also demonstrate a shift in focus toward domestic shipbuilding. Yet the distribution of newer IRIN vessels seems to indicate that the Iranian regime is as concerned about the Caspian Sea as it is about the Persian Gulf; determining the intended destination of the remaining four Moudge-class frigates may offer some insight into Iran’s future strategic priorities.

The countries of the Gulf Cooperation Council have been slower to develop or expand upon their naval forces. Oman, the UAE, and Qatar are actively seeking corvettes but it will still be several years before their respective plans for modernization can be realized. Bahrain and Kuwait are complacent on corvettes, while Saudi Arabia has apparently limited its own plans to whatever package the United States offers. That the Gulf states have not sought to keep up with the expansion of IRIN may in part be due to a security dependence on the US Navy’s Fifth Fleet, as well as multinational forces like Combined Task Force 152. This dependence has been exacerbated by the sustained downfall of Iraq since 1991 as a counterbalance for Iran in the region.

The strategic makeup of the Persian Gulf aside, the next few years in the region will be interesting for corvette enthusiasts. Whether it is the revelation of the Royal Saudi Navy’s package with the US Navy and Lockheed Martin, the unveiling of Iran’s Sahand-class frigate’s capabilities or the final choice of the Qatari Navy’s corvette, there will be plenty to keep everyone on their toes.

Paul Pryce is a Junior Research Fellow at the Atlantic Council of Canada. With degrees in political science from universities in both Canada and Estonia, he has previously worked in conflict resolution as a Research Fellow with the OSCE Parliamentary Assembly. His research interests include African security issues and NATO-Russia relations.

What is a Corvette? And What Next?

By Chuck Hill

Classification of surface warships as cruisers, destroyers, frigates, or corvettes, has become like pornography. There are no generally accepted definitions, but “I know it when I see it”–except that everyone sees it a little differently.

Since this is “Corvette Week” what are we really talking about?

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My Combat Fleets of the World, 16th Edition, which I have used here extensively for reference, defines Corvettes as, “Surface Combatants of less than 1,500 tons but more than 1,000 full load displacement–essentially, fourth rate surface combatants.”  But goes on to note that “…the designation as used here essentially refers to smaller frigates and does not correspond to the European concept of corvettes as any warship larger than a patrol craft but smaller than a frigate.” I feel to confine the definition within a 500 ton range is too restrictive. In fact it would have excluded the Castle class corvettes of WWII as too large, and other corvettes as too small.

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Royal Navy Photograph of Castle class corvette HMS Denbigh Castle (K696)

Pre-WWII

During the age of sail, corvettes were originally warships typically smaller than a frigate, but larger than a sloop, usually with guns on a single deck. Some ships continued to be called corvettes as steam was introduced, but in the Royal Navy, in 1877, corvettes along with sloops and frigates were subsumed under the new designation “cruisers.” Corvettes, as a type, essentially disappeared from the English naval lexicon until 1939. The term was kept alive in some navies (including the French, German, and Italian) as a rank that translated corvette-captain, a rank generally equal to Lieutenant Commander.

World War II

Corvettes as a type reemerged just prior to WWII. As it became clear that U-boats would be a major threat, Britain saw the need for an escort vessel that could be built quickly and in large numbers, in yards that had not been considered capable of building warships. Just before WWII, they ordered the first of 267 “Flower Class” corvettes that were built in the UK and Canada. They modified the design for a whale catcher named Southern Pride, enlarging it to 205 feet overall and a displacement of 1245 to 1390 tons. They were terrible warships, weakly armed, cramped, uncomfortable, and slow. Single screw, reciprocating steam propulsion gave them a maximum speed of only 16.5 knots, a knot slower than a typical (Type VII) surfaced U-boat. They were originally intended only for coastal operations, but because of their long range, they were thrown into the Battle of the Atlantic, where they were by far the most numerous transatlantic convoy escorts for the critical early years, taking slow merchant convoys across the mid-Atlantic air gap, while the Home Fleet’s more capable, but shorter legged, fleet destroyers were generally held back to escort the battle fleet or met convoys only as they approached the British Isles.

File:HMS Polyanthus (K 47).jpg
Flower Class Corvette HMS Polyanthus, Source =www.oldships.org.uk, Author =Leidseplein Date =1943-09-

Reportedly Winston Churchill had a hand it designating this new class “corvettes,” probably in an attempt to make them appear more glamorous than the term “patrol vessels” which had been applied to similar vessels previously. Two years after the re-introduction of the term “corvette,” the term “frigate” was also resurrected to describe another war emergency escort program, this one more complex and more capable but still using reciprocating steam propulsion. Larger commercial yards converted to making frigates (301 to 307 ft, 1920 to 2420 ton), but smaller yards continued to make corvettes of the improved Castle class (252 ft, 1590 to 1630 tons), while naval yards continued to produce small numbers of sloops like the Black Swan class that were the true premier ASW escorts of the Royal Navy.

Australia also built corvettes, 60 ships of the similar but even smaller, slower Bathurst Class (186 ft). Initially they were classified as minesweepers, but found more employment as escorts, so were more frequently referred to as corvettes.

File:HMAS FremantleSLV Green.jpg
Bathurst-class corvette, HMAS Fremantle, State Library of Victoria

Japan, Germany, and Italy all made similar escort ships, but only the numerous Italian  Gabbiano class (193 foot, 728 tons, with combined diesel or electric propulsion no less),  were actually referred to as corvettes.

All of the WWII corvettes were primarily ASW escorts, but their were a number of classes of vessels, many built prior to the war, that share DNA with today’s missile armed corvettes. These were small, fast, torpedo armed vessels that resembled destroyers, but most had a standard displacement of 1000 tons or less. Usually they were referred to as “torpedo boats.”  Japan built twelve, The Germans built 48 (the last 15 were large enough to have been considered destroyers in other navies). The French Navy completed twelve. The Italians completed 69 (some of which were closer to frigates or destroyer escorts). The Italian Spica class (269 ft, 885 to 1,030 ton, 34 knots) may serve as an example.

spica class
Italian Spica Class torpedo boat

Generally, the war emergency programs had one thing in common. They were not the ships these navies would have chosen to build in peacetime. In wartime priorities change; planning horizons contract. Producibility may trump quality. They were all compromised in some fashion–in their speed, survivability, weapons, or economy of operation. Corvettes filled a need for large numbers of escorts, but after the war, most were quickly discarded.

The MCM Connection

The Flower Class Corvettes were originally also equipped to sweep mines. As noted the Australian Bathurst Class began life as minesweepers. While the US built no “corvettes” during the war, the minesweepers of the Raven (220 foot/1040 tons), Auk (221 foot/1,250 tons), and Admirable ((180 foot) classes frequently functioned in this role. In fact, with minor modification Admirable class ships were redesignated PCEs (Patrol Craft, Escort). All these minesweepers were built with sonar. By the end of the war, most were equipped with hedgehogs, depth charge projectors (K-guns) and dual depth charge racks, having enjoyed priority for ASW equipment second only to destroyer escorts.

File:PS-74 Rizal.jpg
Former Auk class minesweeper still serving in the Philippine Navy as Corvette BRP Rizal (PS-74), US Government photo, 050822-N-6264C-145 Sulu Sea (Aug. 22, 2005)

Post WWII

Since the end of WWII corvettes have generally fallen into two categories, with some designs attempting to incorporate elements both types. They tend to be either:
—Small, fast, missile armed vessels optimized for ASuW, like Sweden’s Visby Class (40 knots, 239 ft, 650 tons) usually expected to operate in groups, either with others of their kind or acting as flagships for even smaller missile boats, or
—Smaller versions of frigates with moderate speed optimized for patrol and presence in peacetime and escort during wartime like the Damen designed SIGMAs or  India’s Kamorta Class (25 knots, 358 foot oa, 3100 tons).

File:K33 HMS Haernosand Karlskrona Marindagen2008.jpg
Visby class Corvette, HMS Härnösand.
File:Kri-diponegoro-1600-1200.jpg
SIGMA class corvette.

Largest Operators of Corvettes

The largest operator of corvettes is Russia with approximately 53 (3 Buyan, 1 Buyan M, 7 Parchim II, 23 Grisha V, 4 Grisha III, 2 Dergach Project 1239, 13 Nanuchka) (80 if you count the 27 Tarantuls that fall slightly below the 500 ton threshold I have assumed).
India, China, South Korea, Indonesia, and Italy also maintain large numbers of corvettes.

File:Type 056 corvette 583 Ganzhou.jpg
Chinese Type 056 corvette 583 Ganzhou.

Corvettes in the USN

While the US Navy has never built corvettes for its own use, the type is not without precedence in the US.

In the early days of WWII, when the US navy was desperately short of escorts, 18 Flower class corvettes were transferred to the USN. Eight of those were manned by USCG crews.

File:USS Intensity (PG-93).jpg
Coast Guard manned Flower Class Corvette USS Intensity (PG-93), mid-1943. Former HMCS Fennel (K194).

In the 50s the Navy was interested in experimenting with types that might be built hurriedly in an emergency. The result was the four ships of the Claude Jones class (DE-1033-1036) built by Avondale between 1956 and 1959. At 312 feet long and 2000 tons, they were essentially the same size as the preceding Dealey Class, but they were  simplified, diesel powered, slower, and more lightly armed. These ships were really a update of the corvette concept of a cheap simple escorts that lent itself to rapid construction. (Similarly about the same time the British were building 14 HMS Blackwood Class  (Type 14) that were “2nd Rate Frigates” of 1536 tons, powered by a single shaft steam turbine plant with no gun larger then 40mm.)

USS Claude Jones (DE-1033)
USS Claude Jones (DE-1033)

In the late 1960s the US built four corvettes, given US hull numbers PF-103 to PF-106, that were immediately turned over to the Iranian Navy. They became the Bayandor Class (275 feet long, 1,135 tons).

In the early ’70s, two additional PF-103 class ships (PF-107 and 108), built to a modified design, were delivered to Thailand’s Navy. These were the Tapi Class.

Between 1977 and 1983 Tacoma Boat built a class of four CODOG powered “PCG” for Saudi Arabia, the Badr class, 245 feet, 1,038 tons, 30 knots.

Between 1983 and 1987 Tacoma Boat built two diesel powered “PFMMs” for the Thai Navy Ratanakosin class 252 foot, 960 tons, 26 knots.

Between 1989 and 1995 Northrop Grumman Litton built three CODOG Corvettes for the Israeli Navy, the Sa’ar 5 class, (281 foot, 1,275 tons, 33 knots).

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American built Sa’ar 5 missile corvettes. Photo via Flickr.

Between 2008 and 2013, VT Halter Marine has been building a class of four missile corvettes for the Egyptian Navy, the  Ambassador MkIII class (205 feet, 700 tons, 41 knots). The first has already been delivered.

An undated photo of the ENS S. Ezzat, an Egyptian Fast Missile Craft. VT Halter Marine Photo
An undated photo of the ENS S. Ezzat, an Egyptian Fast Missile Craft. VT Halter Marine Photo.

While the Littoral Combat Ships are not normally considered corvettes, on June 10, 2013, Rear Admiral John F. Kirby, the Chief of Information for the Navy called them Corvettes. Without a mission module or aviation detachment, they are really more like OPVs. But when the Mine Warfare module is mounted they become MCM vessels. When an ASW or ASuW module is mounted, they start to look like corvettes.

The Claude Jones class ships were transferred to the Indonesian Navy and continued in service there until 2006. Of the six PF-103 class ships, two Iranian ships were lost in combat with Iraq, but the remaining four are still in service with the Iranian and Thai Navies and have been updated. The Badr class and the  Ratanakosin class are still in service with their respective navies, and the Sa’ar Vs are still the most advanced surface ships in the Israeli Navy. All but the two Thai Navy Ratanakosin class (PF-107 and 108) have been equipped to launch anti-ship cruise missiles.

The Coast Guard Connection

During WWII Coast Guard Cutters were frequently used as ASW escorts, some quite successfully, filling corvette and frigate roles. After the war, new construction frequently included provision for ASW systems either as built or as planned upgrades in the case of a major conflict.

The 16 Reliance class Medium Endurance Cutters (210 feet, 1,050 tons, 18 knots) delivered 1964 to 1969, were built with provision for adding sonar, hedge hogs, and torpedo tubes. They were originally to have been designated PCs. a designation shared with the sub chasers of WWII.

The 12 Hamilton Class High Endurance cutters (378 feet, 3,050 tons, 29 knots) completed 1967 to 1972, were built with ASW systems installed and their systems were upgraded and provision for harpoon installed 1989 to 1992. As built, they were not the equal of contemporary Destroyer Escorts with their AN/SQS-26 sonars, but were comparable to those built only a few years before. An argument can be made that these ships, as built and later modified, could be considered, if not frigates, at least corvettes.

USCGC Mellon after upgrades including Harpoon, CIWS, and support for LAMPS

The thirteen Bear class cutters (270 feet, 1,780 tons, 19.5 knots) completed 1983 to 1990, were built without ASW systems, but had provision for adding a towed array and supporting a LAMPS I helicopter. If these systems had been provided, then the ships might have also been considered corvettes.

The Coast Guard’s National Security Cutters, of the Bertholf class (eight ships planned, 418 ft/4,500 tons) have no installed ASW systems or ASCMs, but they do have excellent aviation support facilities and the ship has been marketed as the basis for a frigate program. Aside from Exocets carried by the French ships, they are in most respects more capable warships than the Floreal “light surveillance frigates” (307 ft/2950 tons) and similar to the French Lafayette Class frigates (410 ft/3,600 tons) which also currently have no sonar.

USCGC Waesche by Yerba Buena Island.
USCGC Waesche by Yerba Buena Island. U.S. Coast Guard photo ID: 100228-G-2129M-004.
1
French Floréal-class frigate
The Coast Guard is in the process of procuring a new class to replace its Medium Endurance Cutters. The resulting ship is likely to be similar to the Floreal class (90 to 100 meters in length and 2500 to 3500 tons) but faster and will share sensors and some weapons with the Bertholf class and the Littoral Combat Ships. Addition of ASW or ASCM systems would result in ships many would classify as light frigates or corvettes.

Bottom Line–What is a Corvette?

Corvettes slot under frigates but above patrol boats or missile boats as a classification of surface combatants. To me, this means that they are the smallest or perhaps least capable ocean-going warships. This is a bit of a stretch for Corvettes like the Visby, but in fact the Swedes have deployed even smaller warships to the Indian Ocean for counter piracy operations. That sets the low end of the the displacement range at about 500 tons, but when we look for an upper limit, it seems a moving target, with no similar performance based limit.

The US and Britain already build destroyers the size of WWII cruisers. Germany and in the near future Britain will build frigates over 6,000 tons full load. Japan’s Coast Guard has OPVs displacing 9,350 tons full load.  If we tripled the displacement of WWII corvettes as we have done with WWII Frigates and Destroyers, Corvettes could displace almost 5,000 tons, so I don’t think displacement is a reliable determinant.

Strict naval vessel construction standards don’t necessarily distinguish a corvette from an OPV either. They were not applied to the original “Flower” class, and they don’t apply to the Damen designed Sigma class, built or building for Indonesia, Morocco, and Vietnam, or to the French Lafayette class (also operated by Taiwan, Singapore, and Saudi Arabia) and Floreal class (also operated by the Moroccan Navy) which are rated as frigates but which it might be argued are actually corvettes.

The only metric that doesn’t seem to have changed much over the last 70 years is crew size. Corvettes generally have crews of 120 or less, frigates from 120 to perhaps a bit over 200, while destroyer crews begin slightly under 200 and go up to about 350, and cruiser crews are larger still. The DDG1000s will apparently have a frigate sized crew, but their final crew may be larger than currently planned. OPV crews tend to be corvette sized or smaller.

Just as the difference between Spruance Class Destroyers and Ticonderoga Class cruisers was mission and associated equipment, not displacement, the differentiation between the various types of warships and between Offshore Patrol Vessels (OPVs) and corvettes may simply comes down to their missions and equipment. OPVs include a wide range of ships, but the common thread, generally accepted, is that they have no ASW weapons, no heavy anti-ship cruise missiles, and only a self-defense AAW capability. Adding an ASW capability and/or cruise missiles would convert an OPV into a corvette. Perhaps they would not make very good warships, but then the original Corvettes weren’t very good warships either, but they served a vital role. Conversely an old frigate or corvette, stripped of all its weapons except a medium caliber gun and heavy machine guns would become an OPV, even if it nominally retained its frigate or corvette designation as in the case of Portugal’s Joao Coutinho and Baptista de Andrade class or some of Italy’s Minerva class.

If we had no history, and we could start ship designations on “a clean sheet of paper” we might define ships types based on their missions and equipment, saying destroyers are vessels designed with robust capacity to perform well in all three major surface combatant warfare areas, AAW, ASuW, and ASW. Frigates are designed to perform well in only two missions areas  (with possibly modest self defense capability in the third). Corvettes would be single mission specialists with only modest capability in the other two missions (if at all). OPVs would be vessels equipped for missions that did not require robust capabilities in any of these three mission areas. All four types might be called generically “cruisers” which would bring that designation back to its original meaning, a vessel smaller than a ship of the line that can operate independently.

The Future of Corvettes

WWII corvettes were small ships packed with crew and weapons.They were small because there was an urgent need for many ships that could not be met by the shipyards that normally built warships. They were a way of making the small commercial yards serve the war effort. If we are ever engaged in a prolonged conflict against a near peer adversary we may again resort to a similar expedience. If so, the resulting corvette is more likely to be based on a petroleum industry offshore support vessel rather than a whaling or fishing vessel.

But when ships are built in peace time, for a 20 to 40 year life, other factors beside construction cost start to dominate. In the West, crew costs weigh heavily, while increasing hull size appears less important, provided we do not load up the larger hull with additional systems which will in turn drive up crew costs. Larger hulls are more seaworthy, allow greater endurance, and may be made quieter. They may even be more economical to operate and maintain because of easier access.

Some European Countries that formally operated a number of Corvettes seem to have abandoned the type in favor of ships with more range and better seakeeping including The Netherlands, Denmark, and Norway. Denmark has instead produced frigates and a novel class of ships, the Absalon Class “support ships,” (450 ft/6,600 tons) that include a relatively large hull of modest speed, with a relatively small crew of about 100, and a large reconfigurable spaces–an open one topside midships where missile systems can be placed and a “garage” area under the flight deck that can accommodate vehicles and containerized loads. These ships are perhaps too large to be considered corvettes, but they are not nearly so well armed as the frigates of the similarly sized Iver Huitfeldt-class. They do have characteristics I would expect to see on future corvettes, a relatively commodious hull (because “steel is cheap and air is free”), a relatively small crew (because that is the most expensive component over the life-cycle of the ship), and reconfigurable spaces and weapon systems, that allow the ships to be adapted to different missions (because that is allow us to hedge our bets regarding what capabilities will be needed, while allowing that minimal crew over most of the life of the ship).

Because Corvettes are always compromised, they are likely to be controversial. Many will not agree with the compromises accepted. That is certainly true of the new American Corvette, the Littoral Combat ship.

In some respects the LCSs may be the prototype of the future corvette, in that it is not particularly small, but they were made cheap to operate with a minimal crew, and they are single mission ships, but with the advantage that the mission can be changed over time, although not as quickly as once advertised. Other aspects of the ship were perhaps not as well thought out, but they will serve a purpose, and perhaps the next generation LCS  or convertible corvette will better meet our needs.

Chuck retired from the Coast Guard after 22 years service. Assignments included four ships, Rescue Coordination Center New Orleans, CG HQ, Fleet Training Group San Diego, Naval War College, and Maritime Defense Zone Pacific/Pacific Area Ops/Readiness/Plans. Along the way he became the first Coast Guard officer to complete the Tactical Action Officer (TAO) course and also completed the Naval Control of Shipping course. He has had a life-long interest in naval ships and history. Chuck normally writes for his blog, Chuck Hill’s CG blog.  

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Corvette Week: Coming Nov. 24-30

November 24 to 30, CIMSEC will be hosting a “Corvette Week”

What kind of radar cross-section is that? Does it even HAVE satellite comms?
What kind of radar cross-section is that? Does it even HAVE satellite comms?

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The Corvette is a type designation little used by the US Navy, and there is not a lot of clarity in defining what constitutes a corvette. We will be examining the type, discussing what they are, their roles, advantages, and weaknesses.

We will also be talking a bit about OPVs since they are in many ways closely related.

CIMSEC members of widely varying backgrounds will provide a variety of views, including an international perspective.

Chuck Hill will be be considering the ship designation and the future of the type and will also introduce the Coast Guard’s new Offshore Patrol Cutter, “…the other LCS”

Przemyslaw Krajewski asks and answers “Corvette. What is it and why it exists?”

Alan Tweedie takes a “Second Look” at the LCS

Armando J. Heredia looks at the proposed Philippine frigate program and attempts to determine if it really a frigate.

Sven Ortmann will look at the air defense requirements for Corvettes.

If you would like to contribute, its not too late.

Flight III – A Piece in The Surface Combatant Puzzle

 

A Lockheed Martin AMDR conceptual depiction.
A conceptual depiction of the Flight III and AMDR.

For a distant observer, commenting on alternatives to the DDG Flight III would be difficult without the well written documents by Congressional Research Service writer Ronald O’Rourke.  His Navy DDG-51 and DDG-1000 Destroyer Programs: Background and Issues for Congress lists most of the program’s considered possible alternatives, reducing the scope of the issue to selecting evaluation criteria and identifying a specific solution.  Besides the considered options there is also a recommendation that could broaden the scope of the discussion:

Conduct a thorough [Analysis of Alternatives (AOA)] in accordance with DOD acquisition guidance for its future surface combatant program to include:
(c) implications of the ability of the preferred ship to accommodate new technologies on future capabilities to determine the most suitable ship to carry [The Air and Missile Defense Radar (AMDR)] and meet near-term [Integrated Air and Missile Defense (IAMD)] requirements and provide a path to far-term capabilities;
(d) implications on future fleet composition;

With the gradual disappearance of frigates from the Navy’s service, the truncation of DDG-1000 to three units, and LCS under critics’ fire, Arleigh Burke is slowly becoming the sole “can-do-all” class of surface combatant. There is an interesting critique of a homogenous ship class force structure related to the history of the Canadian Navy, with the judgment rendered thus:

Force structure planners should be aware that the history of the RCN shows that naval flexibility cannot be derived from a uniform fleet.”

The author, Kenneth Hansen further elaborates his thesis in another article, concluding that  “If the strategic context is complicated, changing, or uncertain, a diversified fleet structure is required.” Armed with such knowledge, let’s step back and reconsider Navy assumptions for its old Future Surface Combatant Program. This envisioned:
• – A DD(X) destroyer for the precision long-range strike and naval gunfire missions;
• – A CG(X) cruiser for the air defense and ballistic missile defense missions; and
• – A smaller combatant called the Littoral Combat Ship (LCS) to counter submarines, small surface attack craft (boat swarms), and mines in heavily contested littoral (near-shore) areas.

Many things have caused the cruiser as originally conceived to become unaffordable, the destroyer (DDG-1000) has grown to the cruiser’s price and size, and LCS is suffering badly from a lack of operable modules. But the concept itself is not dead. The original requirements, changed under the pressures of the economy and a drive for efficiency, asked for an AMDR with a relative capability described as “SPY+30.”  The new solution for DDG Flight III has a relative capability of “SPY +15”, called in a GAO report “marginally adequate“. At the same time Ronald O’Rourke reports states:

As part of the [Maritime Air and Missile Defense of Joint Forces (MAMDJF)] AOA, the Navy identified that DDG 1000 can accommodate a SPY+25 radar. As part of a technical submission to the Navy, BIW, the lead designer for DDG 1000 also identified a possible design for a 21-foot radar on DDG 1000. The Navy did not include a variant with this size radar in the Radar/Hull Study.

Fancy a frigate?
                          Fancy a frigate?

Another conclusion from MAMDJF AOA study was that a smaller number of higher performance ships is preferable to networking less-capable but more numerous ships. On the other hand such a former approach deepens the deficit of cruiser/destroyers. Is there a way out of this trap? As controversial as it seems, it is theoretically possible to reintroduce a hi-lo mix into the surface fleet, consisting of cruisers and frigates. The aim would be to acquire one cruiser and two frigates for a price of two DDG Flight III. The result would be a Navy with a high-capability ship focused on IAMD undistracted by other tasks, such as ASW, with dedicated escorts in numbers allowing it to close the gap in surface combatants hulls. The fleet structure could therefore consist of:

1. Cruisers with the IAMD mission. If DDG-1000 fills this role it can retain its striking capability. Its towed sonar would be eventually cancelled and ASW mission limited to self-defense and shorter ranges. As an intermediate step toward future capabilities, an extant volume search radar could be retrofitted to the three hulls under construction, allowing more time for BMD software development and integration. This cruiser would represent a scaled-down version of CG(X).

2. Frigates would fill the escort mission focused on ASW and anti-air local area defense. For this purpose, a low-end Aegis could be used, possibly combined with a future, economy version of SPY-3 radar. Frigates should resemble the Norwegian Fridtjof Nansen more than the Spanish Alvaro de Bazan-class with a the difference being a higher number of VLS cells. This class promises to be an affordable workhorse of the fleet, doubtful for the DDG Flight III, which looks more and more strategic.

3. DDG-51 and its follow-on class, which opens a discussion about the word “destroyer” in the U.S. Navy. In order to avoid a “can-do-it-all” syndrome, the follow-on class (a differently conceived Flight III perhaps) could specialize in strike and anti-air area defense capabilities without BMD, and limited ASW capabilities similar to the aforementioned cruisers. In other words, this class would represent a return to a more realistic representation of DD(X) idea. A flexible class would be a good companion both to carriers, supporting the strike mission, and to the corvettes below, providing air defense. It is also neutral towards follow-on decisions and permits the class to free up the extra room for needed growth margins.

4. Corvettes, with a mission to “clear littoral clutter” and focus on ASW, ASuW, MCM, and patrol tasks.

Such a mix would also open the path for new technologies like an all-electric drive, a Total Ship Computing Environment (TSCE), or Advanced Gun System (AGS) to develop in the Fleet. New technologies need enough numbers to evolve into something practical, otherwise they become unwanted expensive “gold-plating”. This four-tier structure also offers flexibility for forming surface task forces tailored to changing situations.

Przemek Krajewski alias Viribus Unitis is a blogger In Poland.  His area of interest is broad context of purpose and structure of Navy and promoting discussions on these subjects In his country