Iroquois-class destroyer

Iroquois-class destroyers, also known as Tribal class, are a class of four helicopter-carrying, guided missile destroyers of the Royal Canadian Navy. Launched in the 1970s, they were originally fitted out for anti-submarine warfare, but a major upgrade programme in the 1990s overhauled them for area-wide anti-aircraft defence. HMCS Huron was paid off and later sunk in a live-fire exercise, leaving three ships in the class.

Original design
The ships were originally intended for long-range anti-submarine warfare. Their primary weapon for this role was their complement of two CH-124 Sea King helicopters, which were supported on a large flight deck with a two-helicopter hangar that collectively took up roughly half of the ship's available area. The helicopters could be launched even in high sea states due to their "bear trap" winch system.

The Iroquois represented an uncommon design compromise compared to its contemporaries. Most ships of the same general size and role, like the Royal Navy's Type 22 or US Navy's Oliver Hazard Perry, had much smaller helicopter support areas, typically only the rear ¼ of the ship. These supported a single, small, short-range helicopter, the Westland Lynx or Kaman Seasprite. Such small helicopters were incapable of operating independently of the ship's sensors, and were effectively a system for extending the range of the weapons by carrying them away from the ship before launch.

In contrast, the Iroquois' much larger Sea Kings were able to carry a complete sensor suite and operate at much longer ranges independently of the launch ship. This allowed a single Iroquois to control a much larger area of the ocean, using both its own sensors and those of its helicopters, combining together to scan larger areas. The downside to this design is that the area taken up by the helicopters would normally be given over to other weapon systems.

For anti-submarine use, the helicopters were backed up by two triple-mount torpedo launchers firing Mk.44 and Mk.46 Mod 5 torpedoes and a Limbo Mark 10 depth charge mortar. For other duties, the ships also mounted an Oto Melara 5-in multi-purpose gun and two four-round Sea Sparrow launchers for point anti-aircraft defence. These launchers were located in a protected box on the deck just in front of the bridge area (behind the gun). For firing, the box opened and the battery extended to the sides, requiring some time for them to unlimber.

The ships were powered primarily by two Pratt & Whitney FT12-AH3 of 7,400 shp each, backed up by two more FT4-A2 gas turbines of 50,000 shp each for boost. They were the first large combat ships to be powered entirely by gas turbine. The power from these turbines was used to run the twin shafts through a series of helical gears. One unique feature was the distinctive Y-shaped "Playboy Bunny" funnels, which were designed to exit the exhaust gases to either side of the helicopter deck.

The ships are 425 × 50 × 14 feet (129.8 × 15.2 × 4.4 metres) and 5,000 tonnes displacement. The normal crew complement was 285.

Gulf War modification
HMCS Athabaskan (DDG 282) was deployed on Operation Friction, the Canadian Forces contribution to the international coalition naval task force serving in Operation Desert Shield and Operation Desert Storm (the Gulf War). Athabaskan was the flagship of the Canadian Naval Task Group.

She was hurriedly modified at CFB Halifax in August 1990 prior to the deployment. These modifications included a new mine-avoidance sonar, a Phalanx 20-mm CIWS (mounted over the Limbo mortar well, which was made inoperative) and shoulder launched Blowpipe and Javelin missiles.

TRUMP modifications
The entire class underwent major retrofits in the early 1990s as a part of the Tribal Class Update and Modernization Project (TRUMP). These refits had the effect of re-purposing the ships for area air defence; following TRUMP the Iroquois-class were referred to as air defence destroyers. Their former anti-submarine role was largely transferred to the Halifax-class frigates.

The main weapon of the new design is the Mk.41 VLS, firing 29 SM-2 Block III long-range anti-aircraft missiles. To provide room for the VLS, the original 5-in L54 gun was replaced with the smaller, but much faster firing, Oto Melara 76 mm gun, relocated from the deck to the bridgework above it. A Phalanx CIWS was also added for self-defence. The torpedo tubes were retained, but the Limbo and Sea Sparrow systems were removed.

The modernization also replaced the original Pratt & Whitney FT-12 cruise turbines with newer 12,788 shp 570-KF engines from Allison. The speed remained the same, however, as the weight had increased to 5,100 tons full load. The original split funnel was replaced by a simpler single one, as the exhaust proved not to be a problem.

The TRUMP was intended to be a stop-gap measure, since the radar systems on these ships are outdated. Following TRUMP, the Iroquois-class were intended to be decommissioned by 2010. Defence budget cuts during the mid-1990s resulted in Huron being left without a crew. Huron was paid off in 2005, and sunk in a live-fire exercise in 2007 by her sister ship Algonquin.

There was some preliminary work on a replacement design that was informally termed the Province class. This was confined largely to studies of a much-improved phased array radar system being developed for the Royal Netherlands Navy and German Navy known as APAR. Speculation had been that these new ships would have been similar to an enlarged Halifax-class frigate. Such a design would have had a multi-role capability similar to the Arleigh Burke-class destroyer.

The replacement for the Iroquois class is now known to Canadian naval observers as the Single Class Surface Combatant Project and this project has been included in the National Shipbuilding Procurement Strategy, announced in October 2011. The new vessels will replace both the Iroquois-class and the Halifax-class beginning in the late 2010s. Under the NSPS, the federal government has awarded the combat vessel package to Irving Shipbuilding and includes construction of 15 warships.

HMCS Iroquois (DDG 280)

 * Builders: Flag of Canada.svg Canada (Built at Marine Industries Ltd., Sorel)
 * Laid down: 15 January 1969
 * Launched: 28 November 1970
 * Operator: Royal Canadian Navy
 * Commissioned: 29 July 1972
 * Status: In active service
 * Modifications: 3 July 1992 TRUMP - addition of Mk.41 VLS SM-2 Block III, Phalanx CIWS and Otobreda 76 mm gun; removal of Sea Sparrow SAM
 * Operations: 6 month deployment to the Arabian Sea as a part of Operation Enduring Freedom.

HMCS Huron (DDG 281)

 * Builders: 🇨🇦 Canada (Davie Shipbuilding, Lauzon)
 * Laid down: 1 June 1969
 * Launched: 9 April 1971
 * Operator: Royal Canadian Navy
 * Commissioned: 16 December 1972
 * Decommissioned: 31 March 2005
 * Status: Sunk on 14 May 2007 100 km west of Vancouver Island as part of a SINK-EX named exercise Trident Fury 2007.
 * Modifications: 25 November 1994 TRUMP - addition of Mk.41 VLS SM-2 Block III, Phalanx CIWS and Otobreda 76 mm gun; removal of Sea Sparrow SAM
 * Operations:

HMCS Athabaskan (DDG 282)

 * Builders: 🇨🇦 Canada (Davie Shipbuilding, Lauzon)
 * Laid down: 1 June 1969
 * Launched: 27 November 1970
 * Operator: Royal Canadian Navy
 * Commissioned: 30 November 1972
 * Status: In active service
 * Modifications: 4 June 1994 TRUMP - addition of Mk.41 VLS SM-2 Block III, Phalanx CIWS and Otobreda 76 mm gun; removal of Sea Sparrow SAM
 * Operations: Operation HESTIA

HMCS Algonquin (DDG 283)

 * Builders: 🇨🇦 Canada (Davie Shipbuilding, Lauzon)
 * Laid down: 1 September 1969
 * Launched: 23 April 1971
 * Operator: Royal Canadian Navy
 * Commissioned: 3 November 1972
 * Status: Sustained damage in accident with HMCS Protecteur on Auguest 30, 2013 (Awaiting assessment at CFB Esquimalt)
 * Modifications: 4 June 1994 TRUMP - addition of Mk.41 VLS SM-2 Block III, Phalanx CIWS and Otobreda 76 mm gun; removal of Sea Sparrow SAM
 * Operations: