AN ALTERNATIVE ROYAL NAVY FOR THE 1970s

© Anthony G Williams

During the 1970s the major surface warships of the RN underwent several substantial changes in equipment. Steam plant (or a steam/gas turbine combination) was replaced by all-gas turbine machinery in new designs. The Sea Dart and Sea Wolf SAMs were introduced to replace Sea Slug and Sea Cat, and Exocet anti-ship and Ikara anti-submarine missiles acquired. The old semi-automatic 4.5 inch Mk VI twin mounting was replaced by the new automatic Mk 8. The Limbo anti-submarine mortar was replaced by homing torpedoes. And three new classes of escort ships were developed – Type 42 destroyers, Type 22 anti-submarine frigates and Type 21 general purpose frigates – plus the Invincible class light aircraft carriers.

The purpose of this article is a 'what if?' think piece, looking at what alternative decisions might have been made at this crucial time, and their possible outcomes, within similar overall levels of resources. It must be emphasised that this is not intended to be critical of the decisions made at the time; they were influenced by countless political, financial and practical considerations and I have no reason to doubt that those responsible made the best decisions they could, in the light of the information then available.

The RN in 1970

At the beginning of the 1970s, the major vessels in the RN's surface fleet were as follows (displacements given are standard):

Aircraft Carriers

Cruisers:

Destroyers

Frigates

The RN in 1980

By 1980, the following new classes of ships, or significantly adapted ones, were in service or under construction:

Aircraft Carriers

Destroyers

Frigates

Modified Frigates

Other 1970 ships remaining in 1980

Elements of the Ships: Engines

In deciding what ships might have been designed to enter service by 1980, an important element is the machinery. All three new classes of escorts used the same COGOG (Combined Gas or Gas) plant, which consisted of two propeller shafts, each with one R-R Tyne (4,000-5,000 shp) and one R-R Olympus (25-28,000 shp) gas turbine. The two types of engines could not be used together. These engines were marinised versions of aircraft turboprop and turbojet engines respectively. The ships therefore had 8,000-10,000 shp for cruising, with 50-58,000 shp for burst speed. The Invincible Class had a different COGAG (Combined Gas and Gas) arrangement consisting of two propeller shafts each with two R-R Olympus which could be used singly or together, giving a total power of 112,000 shp.

The COGAG arrangement was also employed in contemporary USN escorts, using two 20-25,000 shp gas turbines per shaft. Two propeller shafts (80,000 shp) were enough for the 6,000 ton Spruance Class destroyers, while one (40,000 shp) sufficed for the 2,700 ton Oliver Hazard Perry Class frigates.

One of the Type 22s (Brave) was fitted with R-R Spey instead of Olympus gas turbines, and these were subsequently fitted to the Duke Class frigates of the 1990s. The Spey is less powerful than the Olympus (around 19,000 shp) but more efficient. It was available for aircraft use in the 1960s, and a marinised version would probably have developed around 15,000 shp at that time.

Proposal: to marinise the Spey in the 1970s rather than the Tyne and Olympus, and to use it in a COGAG arrangement, providing 30,000 shp per shaft, rising to 38,000 with development. This would have had the following advantages:

The disadvantage would have been a higher fuel consumption in low-speed cruising for the two-shaft installations (30,000 shp available, whereas 10,000 was adequate).

Elements of the Ships: Weapons

The Sea Dart was an advanced SAM when introduced, with the advantage over the similar-sized USN SM missiles of an efficient ramjet engine which put its range in the same class as the bigger Extended Range missiles. It utilised a trainable twin launcher (as did SM at the time). The USN later adopted a VLS (Vertical Launch System) for its SMs, as that was simpler and more reliable and the VLS silos could be easily used to launch other missiles of similar size.

The RN purchased the French Exocet anti-ship missile, which was launched from substantial fixed boxes.

The RN also purchased the Australian Ikara anti-submarine missile, which was like a small radio-controlled aeroplane carrying a homing torpedo. It was launched using rocket boosters, and then glided to its target. The installation required a 'zareba'; a circular mounting to launch it from.

Proposal: to develop a VLS system for Sea Dart from the start. This would also be used to house Exocet missiles, and an Ikara-type missile; ideally, the Australians would be persuaded to develop Ikara to fit. The advantages would be:

Sea Wolf was (and remains) a very effective short-range AA and anti-missile system. It was introduced in a trainable six-round launcher, now replaced by a VLS. Ironically, early in its development in the 1960s it was tested with a VLS and it is unclear why this was not proceeded with then. The missile system was also the subject of a very protracted development which greatly increased its cost and delayed its entry into service.

Proposal: develop Sea Wolf as a VLS system from the start, and concentrate on getting the initial version into service quickly, leaving performance improvements to later software upgrades. Advantages:

The 4.5 inch Mk 8 gun was (and remains) a satisfactory but unremarkable shore bombardment and secondary anti-ship MCG (Medium Calibre Gun). However, the opportunity could have been taken to strike deals with other countries over 'weapon swaps'; e.g. acquiring the Italian 5 inch and 3 inch OTO Melara guns, or the French 100 mm, or the Swedish 120 mm Bofors, in return for Sea Wolf or Sea Dart systems.

Proposal: that suitable foreign guns be acquired by exchange instead of developing the 4.5 inch Mk 8. Advantages:

                    Cost of developing 4.5 inch Mk 8 avoided

                    Opportunities to extend export sales for other systems

The RN continued to rely for light automatic cannon on the basically WW2 era 20mm Oerlikon and 40mm Bofors, until after the Falklands when there was a rapid switch to modern Oerlikon weapons: the 20 mm KAA in a single mounting, and the 30 mm KCB in single or twin stabilised mountings.

Proposal: to adopt the 30 mm KCB in a single stabilised mounting for the new ships. Advantages:

Proposed Ship Classes

To summarise, the RN acquired 14 new destroyers, 14 new anti-submarine frigates and 8 less expensive new general-purpose frigates to three designs from the 1970s onwards, a total of 36 new escort ships. In addition, 21 Leander class ships were extensively (and expensively) modified, with entirely new weapon systems.

Several problems with these decisions emerged, largely because the nature of the expected threat changed. In the 1970s the RN was thinking almost exclusively about the threat to North Atlantic trade posed by Soviet surface ships, submarines and long-range missile-carrying aircraft. The ships procured therefore tended to be specialised for particular functions (anti-air, anti-ship or anti-submarine) except for the less capable general-purpose Type 21 frigates.

The 1982 Falklands War drove home the lesson that all ships need to have general-purpose capabilities, even if they are biased towards one major function. So the last batch of the gunless (apart from 40 mm Bofors) Type 22 frigates was modified to carry a 4.5 inch gun, as was the design of the succeeding Type 23 Duke Class ships.

Bearing this in mind, it might have been better to consider a high/low mix of escorts, with some having the full range of functions, and other being smaller and less expensive but still with good all-round capabilities.

Proposal: that two different classes of escorts be developed instead of three, as follows:

Destroyer – two-shaft, c.5,500 tons, with c.60 VLS for Sea Dart/Exocet/Ikara, also VLS Sea Wolf, MCG, 30 mm, and a flight deck and hangar for one Sea King or two Sea Lynx helos.

Frigate – one-shaft, c.2,750 tons, with c.24 VLS for Exocet/Ikara only, also VLS Sea Wolf, MCG, 30 mm, and a flight deck and hangar for a Sea Lynx.

The key question is: could these have been afforded?

In ship terms (steel and machinery), the destroyer would cost about the same as a Type 22 or 42 (the larger ship being balanced by the less expensive machinery), but the weapon fit would be considerably more expensive as it would essentially consist of both types of ship combined. Even allowing for the possible cost savings in weapon procurement indicated, each destroyer would probably cost half as much again as a Type 22 or 42.

The frigate would basically be significantly cheaper than the similar-sized Type 21 because of the one-shaft machinery, but again the weapons fit would be considerably more expensive. In compensation, the Exocet/Ikara/Sea Wolf modifications to the Leander class would have been unnecessary, resulting in a considerable saving. The Leanders would simply be phased out as the new frigates were introduced.

There is another important element in the savings, and that is the crew. The RN went through a manning crisis in the late 1970s, and the more rapid replacement of the steam Leanders by gas-turbine ships would have led to crew savings.

Overall, it seems reasonable to project a target of 12 destroyers and 24 frigates to be constructed over the 1970s and 1980s for a similar cost to the actual procurements.

It should be noted that the versatility of the frigates in particular would have made them far more attractive on the export market than the specialised ships actually acquired. A stretched version of the frigate, to accommodate a  radar and crew needed for Sea Dart, could also have been very attractive to navies looking for an economical escort with some air defence capability. It could have been a serious rival to the American Oliver Hazard Perry Class.

The Invincible Class carriers were bedevilled with political compromises in their development (being originally known as 'Through-Deck Cruisers' in an attempt to fool the Labour government, which was opposed to aircraft carriers). This led to them being planned with the unnecessary armament of Sea Dart and Exocet (although the latter was not fitted). They would certainly have been far better served by a Sea Wolf installation instead.

Implications: the Falklands War

Assuming that the new ships could have been built at a rate of one destroyer and two frigates per year over a period of 12 years, with the first ones commissioning in 1975, then 7 destroyers and 14 frigates would have been in service, fully worked-up, at the time of the 1982 Falklands War. Every one of them would have had Sea Wolf, backed up by 30 mm guns, which would have made them vastly more effective in the savage battles with Argentinian aircraft around San Carlos Water. Each one would also have had an MCG for shore bombardment. Equipping Invincible with Sea Wolf would have reduced the risk to the carrier, possibly enabling her to operate closer to the battle zone to the benefit of Sea Harrier availability. Of course, a great benefit would also have resulted from the earlier introduction of the Sea King Searchwater AEW helos, developed in a rush just too late for the Falklands.

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