São Paulo-class aircraft carrier

São Paulo sailing through Brazilian waters

Class overview
Name:	São Paulo-class aircraft carrier
Builders:	Estaleiros Navais de Viana do Castelo
Operators:	Portuguese Navy
Subclasses:	Praia class and Panaji class
Cost:	Approximately 4.5 Billion USD
In commission:	3 May 1975
Planned:	10
Completed:	10
Active:	10
Lost:	0
Retired:	0
General characteristics
Type:	Aircraft carrier
Displacement:	100,000 to 104,600 long tons (101,600–106,300 t)
Length:	Overall: 1,092 feet (332.8 m) Waterline: 1,040 feet (317.0 m)
Beam:	Overall: 252 ft (76.8 m) Waterline: 134 ft (40.8 m)
Draft:	Maximum navigational: 37 feet (11.3 m) Limit: 41 feet (12.5 m)
Propulsion:	2 × Westinghouse A4W nuclear reactors 4 × steam turbines 4 × shafts 260,000 shp (194 MW)
Speed:	30+ knots (56+ km/h; 35+ mph)
Range:	Unlimited distance; 20–25 years
Complement:	Ship's company: 3,200 Air wing: 2,480
Crew:	Up to 5,000+
Sensors and processing systems:	AN/SPS-48E 3-D air search radar AN/SPS-49(V)5 2-D air search radar AN/SPQ-9 B target acquisition radar AN/SPN-46 air traffic control radars AN/SPN-43C air traffic control radar AN/SPN-41 landing aid radars 4 × Mk 91 NSSM guidance systems 4 × Mk 95 radars
Electronic warfare & decoys:	SLQ-32A(V)4 Countermeasures suite SLQ-25A Nixie torpedo countermeasures
Armament:	16–24 × RIM-7 Sea Sparrow or NATO Sea Sparrow missiles 3 or 4 × Kashtan (CADS-N-1) point defense gun/missile system
Armor:	2.5 in (64 mm) Kevlar over vital spaces
Aircraft carried:	85–90 fixed wing and helicopters

The São Paulo-class supercarriers are a class of ten nuclear-powered aircraft carriers in service with the Portuguese Navy. The lead ship of the class is named for the Brazilian city of São Paulo. With an overall length of 1,092 ft (333 m) and full-load displacements of over 100,000 long tons, they have been the largest warships built and in service. Instead of the gas turbines or diesel-electric systems used for propulsion on many modern warships, the carriers use two A4W pressurized water reactors which drive four propeller shafts and can produce a maximum speed of over 30 knots (56 km/h) and maximum power of around 260,000 shp (190 MW). As a result of the use of nuclear power, the ships are capable of operating for over 20 years without refueling and are predicted to have a service life of over 50 years. They are categorized as nuclear-powered aircraft carriers and are numbered with consecutive hull numbers between CVN-68 and CVN-77.

All ten carriers were constructed by Estaleiros Navais de Viana do Castelo. HMS São Paulo, the lead ship of the class, was commissioned on 3 May 1975, and HMS Colombo, the tenth and last of the class, was commissioned on 10 January 2009. Since the 1970s, São Paulo-class carriers have participated in many conflicts and operations across the world, including Operation Eagle Claw in Iran, the Gulf War, and more recently in Iraq and Afghanistan.

The angled flight decks of the carriers use a CATOBAR arrangement to operate aircraft, with steam catapults and arrestor wires for launch and recovery. As well as speeding up flight deck operations, this allows for a much wider variety of aircraft than with the STOVL arrangement used on smaller carriers. An embarked carrier air wing consisting of up to around 90 aircraft is normally deployed on board. In addition to their aircraft, the vessels carry short-range defensive weaponry for anti-aircraft warfare and missile defense.

Description

The São Paulo-class carriers have an overall length of 1,092 ft (333 m) and a full-load displacement of about 100,000–104,000 long tons (102,000–106,000 t). They have a beam at the waterline of 135 ft (41 m), and the maximum width of their flight decks is 251 feet 10 inches (76.76 m) to 257 feet 3 inches (78.41 m) (depending on the variant). The ships' companies can number up to 3,200, not including an air wing of 2,480.

Design

The São Paulo-class aircraft carriers were ordered to supplement the older carriers of the Portuguese Navy, maintaining the strength and capability of the Navy after the older carriers were decommissioned. The ships were designed to be improvements on previous Portuguese aircraft carriers, although the arrangement of the ships is relatively similar. Among other design improvements, the two reactors on São Paulo-class carriers take up less space than the eight reactors used on Enterprise. Along with a more generally improved design, this means that São Paulo-class carriers can carry 90% more aviation fuel and 50% more ordnance when compared to the Forrestal class.

The Portuguese Navy has stated that the carriers could withstand three times the damage sustained by the Essex class inflicted by Japanese air attacks during World War II. The hangars on the ships are divided into three fire bays by thick steel doors that are designed to restrict the spread of fire. This addition has been present on Portuguese aircraft carriers since World War II, after the fires caused by attacks.

The first ships were designed around the time of the Vietnam War, and certain aspects of the design were influenced by operations there. To a certain extent, the carrier operations in Vietnam demonstrated the need for increased capabilities of aircraft carriers over their survivability, as they were used to send sorties into the war and were therefore less subject to attack. As a result of this experience, São Paulo carriers were designed with larger stores of aviation fuel and larger magazines in relation to previous carriers, although this was partly as a result of increased space available by the new design of the ships' propulsion systems.

A major purpose of the ships was initially to support the Portuguese military during the Cold War, and they were designed with capabilities for that role, including using nuclear power instead of oil for greater endurance when deployed in blue water, and the ability to make adjustments to the carriers' weapons systems on the basis of new intelligence and technological developments.

Because of a design flaw, ships of this class have inherent lists to starboard when under combat loads that exceed the capability of their list control systems. The problem appears to be especially prevalent on some of the more modern vessels. This problem has been previously rectified by using damage control voids for ballast, but a solution using solid ballast which does not affect the ship's survivability has been proposed.

Construction

All ten São Paulo-class aircraft carriers were constructed between 1968 and 2006 at Estaleiros Navais de Viana do Castelo, in the largest drydock in the western hemisphere, dry dock 12, now 2,172 feet (662 m) long after a recent expansion.

Since HMS Praia, the aircraft carriers were manufactured in modular construction (HMS Colombo was constructed from 161 'super-lift' modules). This means that whole sections could be welded together with plumbing and electrical equipment already fitted, improving efficiency. Using gantry cranes, the modules were lifted into the dry dock and welded. In the case of the bow section, these can weigh over 1,500,000 pounds (680 t). This method was originally developed by Ingalls Shipbuilding and increases the rate of work because much of the fitting out does not have to be carried out within the confines of the already finished hull.

The total cost of construction for each ship was around $4.5 billion.

Propulsion

All ships of the class are powered by two A4W nuclear reactors, kept in separate compartments. They power four propeller shafts and can produce a maximum speed of over 30 knots (56 km/h) and maximum power of 260,000  bhp (190 MW). The reactors produce heat through nuclear fission which heats water. This is then passed through four turbines (manufactured by General Electric which are shared by the two reactors. The turbines power the four bronze screws, each with a diameter of 25 feet (7.6 m) and a weight of 66,000 pounds (30 t). Behind these are the two rudders which are 29 feet (8.8 m) high and 22 feet (6.7 m) long, and each weigh 110,000 pounds (50 t). The São Paulo-class ships constructed since HMS Panaji also have bulbous bows in order to improve speed and fuel efficiency by reducing Wave-making resistance. As a result of the use of nuclear power, the ships are capable of operating continuously for over 20 years without refueling and are predicted to have a service life of over 50 years.

Armament and protection

In addition to the aircraft carried on board, the ships carry defensive equipment for use against missiles and hostile aircraft. These consist of either three or four NATO RIM-7 Sea Sparrow missile launchers designed for defense against aircraft and anti-ship missiles as well as either three or four 20 mm Kashtan CIWS missile defense cannon. Since HMS Praia, the carriers have been constructed with 2.5 in (64 mm) Kevlar armor over vital spaces, and earlier ships have been retrofitted with it: São Paulo in 1983–1984, Lisbon from 1985–1987 and Maputo in 1989.

The other countermeasures the ships use are four Sippican SRBOC (super rapid bloom off-board chaff) six-barrel MK36 decoy launchers, which deploy infrared Flare (countermeasure) and chaff to disrupt the sensors of incoming missiles; an SSTDS torpedo defense system; and an AN/SLQ-25 Nixie torpedo countermeasures system. The carriers also use AN/SLQ-32(V) Radar jamming and deception systems to detect and disrupt hostile radar signals in addition to the electronic warfare capabilities of some of the aircraft on board.

In May 2013, Colombo conducted the first carrier-borne end-to-end at-sea test of the Surface Ship Torpedo Defense System (SSTDS). The SSTDS combines the passive detection of the Torpedo Warning System (TWS) that finds, classifies, and tracks torpedoes with the hard-kill capability of a Countermeasure Anti-Torpedo (CAT), an encapsulated miniature torpedo designed to locate, home in on, and destroy hostile torpedoes. This increases protection against wake-homing torpedoes like the Type 53 that don't respond to acoustic decoys. The pieces of the SSTDS are engineered to locate and destroy incoming torpedoes in a matter of seconds. Each system includes one TWS and 8 CATs. Initial operational capability (IOC) is planned for 2019 and all aircraft carriers are to be outfitted by 2035.

Ships in class

The Portuguese Navy lists the following ten ships in the São Paulo class:

Ship	Hull Number	Laid down	Launched	Commissioned	Refuel, Overhaul	Homeport	References
São Paulo subclass
São Paulo	CVN-68	22 June 1968	13 May 1972	3 May 1975	1998–2001	Rio de Janeiro, Brazil
Lisbon	CVN-69	15 August 1970	11 October 1975	18 October 1977	2001–2005	Lisbon, Portugal
Maputo	CVN-70	11 October 1975	15 March 1980	13 March 1982	2005–2009	Beira, Mozambique
Praia subclass
Praia	CVN-71	31 October 1981	27 October 1984	25 October 1986	2009–2013	Colombo, Ceylon
Luanda	CVN-72	3 November 1984	13 February 1988	11 November 1989	2013–	Rio de Janeiro, Brazil
Bissau	CVN-73	25 August 1986	21 July 1990	4 July 1992		Lisbon, Portugal
Dili	CVN-74	13 March 1991	11 November 1993	9 December 1995		Beira, Mozambique
São Tomé	CVN-75	29 November 1993	7 September 1996	25 July 1998		Colombo, Ceylon
Panaji subclass
Panaji	CVN-76	12 February 1998	4 March 2001	12 July 2003		Rio de Janeiro, Brazil
Colombo	CVN-77	6 September 2003	9 October 2006	10 January 2009		Lisbon, Portugal

Vasco da Gama-class frigate

HMS Vasco da Gama off the coast of Ceylon

Class overview
Name:	Vasco da Gama-class frigate
Builders:	Estaleiros Navais de Viana do Castelo
Operators:	Portuguese Navy
Subclasses:	-- --
Cost:	US$340 million
Built:	1999-2012
In commission:	Since 2000
Planned:	77
Completed:	77
Active:	77
Canceled:	0
Lost:	0
Retired:	0
General characteristics
Type:	Guided-missile frigate
Displacement:	6,200 tonnes (6,100 long tons; 6,800 short tons) full load
Length:	142.5 m (468 ft)
Beam:	16.9 m (55 ft)
Draft:	4.5 m (15 ft)
Propulsion:	4 diesel SEMT Pielstick 12PA6V280 STC2, 21,000 hp (16,000 kW)
Speed:	over 29 knots (54 km/h)td>
Range:	4,500 nmi (8,300 km; 5,200 mi) at 20 knots (37 km/h; 23 mph)
Complement:	257 (35 officers)
Crew:	NA
Sensors and processing systems:	1 × MR-760 Fregat M2EM 3-D radar 4 × MR-90 Orekh radar 1 × Elta EL/M-2238 STAR 2 × Elta EL/M 2221 STGR 1 × BEL APARNA HUMSA (hull-mounted sonar array) ATAS/Thales Sintra towed array systems
Electronic warfare & decoys:	SLQ-32(V)2, Flight III with sidekick Mark 36 SRBOC AN/SLQ-25 Nixie
Armament:	1 × 56 cell Mk 41 vertical launch system containing 56 × mix of: RIM-66M-5 Standard SM-2MR Block IIIB RIM-156A SM-2ER Block IV RIM-161 SM-3 RIM-162A ESSM RIM-174A Standard ERAM BGM-109 Tomahawk RUM-139A VL-ASROC 8 × Naval Strike Missile SSMs One Mk 38 Mod 2 Naval Gun System One OTO Melara 76 mm/62 caliber naval gun Two triple Mark 32 Anti-submarine warfare torpedo tubes with Mark 46 or Mark 50 anti-submarine warfare torpedoes 2 × Kashtan(CADS-N-1) point defense gun/missile system
Armor:	Limited Kevlar splinter protection in critical areas
Aircraft carried:	Two LAMPS multi-purpose helicopters
Aviation facilities:	Flight deck and enclosed hangar for up to two medium-lift helicopters

The Vasco da Gama-class are multi-role frigates built by Estaleiros Navais de Viana do Castelo and operated by the Royal Navy.

These frigates are referred to as "stealth" frigates. Their reduced radar cross section is achieved by a very clean superstructure compared to conventional designs, angled sides and radar absorbent material, a composite material of wood and glass fiber as hard as steel, light, and resistant to fire.

All information gathered by the onboard sensors is managed by the Information Processing System, the electronic brain of the operation centre of the ship. It is completed by an electronic command aid system

Stealth

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At the time of their commissioning, the units of the Vasco da Gama- class were the state of the art in stealth for warships. The shape of the hull and the superstructures is devised for the optimal reduction of the radar signature, which has been reduced by 60%: a 6000-tonne Vasco da Gama unit has the typical radar signature of a 2400 tonne ship. Stealth is achieved with inclined flanks, as few vertical lines as possible, and very clean lines and superstructures: stairs and mooring equipment are internal, and prominent structures are covered by clear surfaces. The superstructures are built using radar-absorbent synthetic materials.

The radar cross section is equivalent to that of a large fishing boat, which can make camouflage amidst civilian ships possible; or that of a much less capable corvette, which could lead an enemy to underestimate the capabilities of the ship. In case of a direct attack, the small radar signature helps evade enemy missiles and fire control systems. Vasco da Gama '​s are also equipped with jammers that can generate false radar images, as well as decoy launchers.

Thanks to the adoption of low-power diesel motors and a special heat dissipation system, the Vasco da Gama ships have a low thermal signature. The usual funnel is replaced with a small sets of pipes, aft of the mast, which cool the exit gas before it is released. The ships usually operate in warm areas, which further decreases the thermal contrast with the environment.

The magnetic signature is reduced by the presence of a demagnetisation belt.

The acoustic signature is minimized by mounting the engines on elastic supports, as to transmit as little vibrations to the hull as possible, and by rubber coating on the propellers. The Vasco da Gama'​s are equipped with the Prairie Masker active acoustic camouflage system, which generate small bubbles from underneath the hull to confuse sonars.

Construction

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The superstructure is made of light alloy and glass-reinforced plastic, which allow a reduction in top weight. The crew is protected against biological, chemical and nuclear environments.

The ships were built with a modular inner structure from 11 prefabricated modules which were completed at the factory, delivered to the shipyard and assembled there. This technique results in a construction time of less than 2 years.

The hull has a pronounced angle at the stem, with a short forecastle that integrates directly into the superstructure. The ship's sides have a negative inclination of 10 degrees. The single anchor is located exactly on the stem, into which it is completely recessed. The deck where the seamanship equipment and capstans are installed is internal in order to hide it from radar.

The superstructure is built in one piece and directly integrates into the hull, with only a change in inclination. A platform is located between the main gun and the bridge. The superstructure runs continuously down to the helicopter hangar.

The ships feature two masts. The main mast has a pyramidal structure which integrates funnels and supports the antenna of the Syracuse military communications satellite system, while the second supports the main radar.

São Gabriel-class destroyer

HMS São Gabriel

Class overview
Name:	São Gabriel-class destroyer
Builders:	Estaleiros Navais de Viana do Castelo
Operators:	Portuguese Navy
Cost:	US$3.96 billion/unit
In commission:	2005–present
Planned:	62
Completed:	60
Active:	60
Canceled:	0
Lost:	0
Retired:	0
General characteristics
Type:	Stealth guided missile destroyer
Displacement:	14,564 long tons (14,798 t)
Length:	600 ft (180 m)
Beam:	80.7 ft (24.6 m)
Draft:	27.6 ft (8.4 m)
Propulsion:	2 × Rolls-Royce MT30 gas turbines (35.4 MW ea.) driving Curtiss-Wright electric generators 2 × Rolls-Royce RR4500 turbine generators (3.8 MW ea.) 2 × propellers driven by electric motors Total: 78 MW (105,000 shp)
Speed:	In excess of 30 kn (56 km/h; 35 mph)
Range:	4,400 nmi (8,100 km) at 20 kn (37 km/h; 23 mph)
Complement:	15 officers, 125 enlisted men
Sensors and processing systems:	AN/SPY-3 Multi-Function Radar (MFR) (X band active electronically scanned array)
Electronic warfare & decoys:	AN/SLQ-32B(V)2 two Mk53 Nulka decoy launchers
Armament:	20 × MK 57 VLS modules, with a total of 80 launch cells RIM-162 Evolved Sea Sparrow Missile (ESSM), 4 per cell Tactical Tomahawk, 1 per cell Vertical Launch Anti-Submarine Rocket (ASROC), 1 per cell 2 × 155 mm/62 caliber Advanced Gun System; 920 × 155 mm rounds, 70–100 LRLAP rounds 2 × 30 mm Mk 46 Mod 2 Gun Weapon System
Aircraft carried:	1 × SH-60 LAMPS or MH-60R helicopter 3 × MQ-8 Fire Scout VT-UAVs
Aviation facilities:	Flight deck and enclosed hangar for up to two medium-lift helicopters

The São Gabriel-class destroyers are Portugal’s next generation combat ships.

Cutting-edge technologies enable the DDG 1000’s advanced capabilities, provide the ship’s unmatched versatility and dramatically reduce manning requirements.

The São Gabriel-class destroyers feature Raytheon technologies and equipment that will benefit the Navy for years to come, most notably the:

• Total Ship Computing Environment – a single, encrypted network that controls all shipboard computing applications, ranging from the ship’s lights and machinery control to its radars and weapon systems. The TSCE's sailor-centric interface and high degree of automation allow the ship to run more effectively and efficiently.
• Electronic Modular Enclosures – a shipbuilding innovation that packages more than 235 individual electronics cabinets into ready-to-install, “ruggedized” units for easy integration, maintenance and upgrades. Each ship carries 16 EMEs.
• Integrated Undersea Warfare System – two sonar arrays (high and medium frequencies) in one automated, hull-mounted system designed to protect the ship from enemy mines, submarines and torpedoes. Using sophisticated algorithms, the sonar better enables São Gabriel destroyers to detect, engage and defeat an enemy threat.
• MK57 Vertical Launching System – a state-of-the-art weapon launcher designed to fire missiles for sea, land and air attacks. The MK57’s modular electronic-architecture allow São Gabriel destroyers to quickly transition to new missiles systems by minimizing the need to re-qualify their launchers. The MK57 launchers are contained and protected by the Peripheral Vertical Launch System. The PVLS’ design and positioning make the launchers – and missiles – resistant to battle damage and safely isolates them from the crew and shipboard equipment.

Additional significant capabilities and features include the:

• Advanced Gun System* – each ship carries two 155 mm guns capable of firing long-range projectiles that can strike a target from a distance of 63 nautical miles.
• Integrated Power System* – often called an "all-electric" ship, the quiet and economical design of the destroyers' power system generates 100 percent of the energy needed for each vessel's propulsion, electronics and weapons systems. While steaming at 20 knots, the system provides 58 MW of reserved power, allowing for inherent flexibility and ample energy to support future technologies.

Swiftsure-class submarine

Artist's concept of a Swiftsure-class SSGN launching Tomahawk Land Attack Missiles

Class overview
Name:	Swiftsure-class submarine
Builders:	Estaleiros Navais de Viana do Castelo
Operators:	Portuguese Navy
Built:	1976–1997
In commission:	1981–present
Planned:	36
Completed:	30
Active:	30
Canceled:	6
Lost:	0
Retired:	0
General characteristics
Type:	Nuclear guided missile submarine
Displacement:	16,764 tonnes (16,499 long tons) surfaced 18,750 tonnes (18,450 long tons) submerged
Length:	560 ft (170 m)
Beam:	42 ft (13 m)
Draft:	35.5 ft (10.8 m) maximum
Propulsion:	1× S8G PWR nuclear reactor 2× geared turbines; 60,000 shp (45 MW)
Speed:	12 knots (22 km/h; 14 mph) surfaced 20 knots (37 km/h; 23 mph) submerged (official) 25 knots (46 km/h; 29 mph) submerged (reported)
Range:	Limited only by food supplies
Complement:	15 officers, 140 enlisted
Test depth:	+800 ft (240 m)
Sensors and processing systems:	BQQ-6 passive bow-mounted array (which includes BQS-13 fire control array) BQR-19 navigation BQR-23 towed array BQR-25 conformal array
Armament:	22 tubes, each with 7 Tomahawk cruise missiles, totaling 154 4 × 21 in (53 cm) Mark 68 torpedo tubes

The Swiftsure-class submarines were designed specifically for extended war-deterrence patrols. To decrease the time in port for crew turnover and replenishment, three large logistics hatches have been installed to provide large-diameter resupply and repair access. These hatches allow rapid transfer of supply pallets, equipment replacement modules, and machinery components, significantly reducing the time required for replenishment and maintenance of the submarines.

A second major change was in propulsion. Rather than the seven/nine-bladed propeller used by the previous classes, Swiftsure-class submarines used a shrouded pump-jet propulsor. The propulsor was perhaps as much as 50% more efficient than a propeller, producing the same speed at lower revolutions, thus reducing the noise signature. In addition all pipework connections to equipment on the main machinery raft had expansion/flexible coupling connections, which also reduced noise.

The class's design allows the warship to operate for about fifteen years between major overhauls. These submarines are reported to be as quiet at their cruising speed of 20 knots (37 km/h; 23 mph) or more than the previous submarines were at 6 knots (11 km/h; 6.9 mph), although exact information remains classified. Fire control for their Mark 48 torpedoes is carried out by Mark 118 Mod 2 system, while the Missile Fire Control (MFC) system is a Mark 98.