Type 12 Whitby Class

Thanks to the Destroyer conversion program, in particular the Type 15, the RN had plenty of information available to them on the best design and layout of a new Escort Ship, coupled with this the experience of the Battle of the Atlantic and the horrific Russian convoys.

The ship would be built around the Limbo Mortar, although the US were less impressed with this weapon and preferred to develop the Hedgehog further. They would introduce their own single barrelled mortar in time, the extraordinary Alpha Weapon, but the US love of rocketry and their advances in homing torpedoes made the ASROC the weapon of choice for the bulk of the Cold War.

The Type 15 were Destroyer Hulls and demonstrated the problem with basing the ship on a Destroyer. A Destroyer typically had it's hull crammed with about 70% of machinary, new ships would need some of that space for modern equipment and improved accomodation.

A cynic might say that the firm avoidance of the Destroyer Escort badge post war was to avoid the controversy over the reduction in the number of engine rooms and boilers that had been used to produce the compact Emergency Class Destroyers and was only now being reversed with the uneasy compromise of the Unit system: alternating two boiler rooms with two engine rooms. Conventional thinking demanded three boiler rooms and two engine rooms as a minimum. The modern Frigate, reborn in the war, had never had even the luxury of the J Type Destroyer with two boiler rooms back to back. Based on merchant ship building practises they gave no pretence at survivability.

In the Type 41 and 61 this was not an issue, with eight diesels feeding two shafts and each diesel effectively a boiler and engine in it's own right the ships had an excellent survivability factor.

The Type 11 had been cancelled, the twin arguments of economics of producing two ASW vessels and the slightly less compelling argument that the ships had to be able to beat the submarines in a race, a point soon to become totally unattainable anyway. In the Type 12 then was now the additional compromise required of both a high speed Fleet Escort and a long range Convoy Escort.

No diesels were available to achieve the magic 30 knots required for Fleet Operations and gas turbines were too radical and untested. The tried and proved steam method would have to be used, together with Turbines which immediatley negated the ethos of the replacement for the River and Loch Frigates which could be built fast, cheaply and in non specialised merchant yards. The common hull also had to be lost, the Type 12 needed to be 2 ft broader in the beam and 30 ft longer to take the smallest power plant that could be designed for it.

In order to shoe horn in a 30 knot steam engine unit all rules had to be scrapped, the final design chosen was from Yarrows, a combination of two Babcock and Wilcox boilers and two English Electric Turbines labelled the Y-100. To achieve the compactness needed the preferred method of twinning boiler and engine together had to be abandoned, the two boilers were mounted side by side and so were the engines, and both had to be in adjacent machinary spaces which meant a hit on either would cripple the ship.

In order to achieve the Range required the engine employed twin reduction gears on the turbines which meant the propellors could be rotated a more efficient low speeds, instead of a 40,000 SHP unit the Type 12 was able to achieve 30 knots with just 25,000 SHP

Primary power was provided by two steam driven Turbo Alternators, although one was placed in each machinary space since they were both steam driven it still meant the loss of the boiler room would knock out all ship power. To overcome this the ship was designed to take two large diesels generators which could independently power the ship, but no standby electric engines were provided so a hit on either machinary space would still bring the ship to a halt in the water.

Perhaps because of this close attention was paid to towing arrangements and the ability of one Type 12 to tow another at almost full speed was proven in trials.

Even with the hull lengthened and broadened to accomodate the power plant the diesels could not be sited below the waterline and the bow was extended to accomodate them in a highly vulnerable position that would also add uncomfortably to the top weight of the ship. To those crews who questioned this arrangement (and we were many!) the less than comforting answer was the ships would most likely take a torpedo which would break her back anyway, or be vapourised by a Nuke. Despite this gloomy outlook the ships were provided with extensive damage control systems, particularly in the provision for re-routing power, much of it based on hard won wartime experience.

At the end of the day the Type 12 was a compromise in that it was expected to fill two roles which the RN had wanted to segregate: Convoy Escort and Fleet Escort, as such it performed neither as well as could be hoped, at 30 knots maximum it was only just up to Fleet Speeds and very heavy on fuel and she lacked the endurance that a diesel powered ship would have enjoyed for Convoy work. However as the RN had learned the hard away just having a proven design to hand which could be adapted and modified to meet current needs was of enormous benifit, the common hull frigates were designed to be mass produced if needed. Only later would it become apparent that any war with Soviet Russia was unlikely to allow time to build new ships.

HMS Tenby, fast, highly manouverable and able to operate in virtualy any weather the Type 12 was the culmination of six years experience fighting the U-Boat and was recognised world wide as the definitive ASW ship.

The hull of the ships was designed to be built in pre-fabricated sections and assembled on site, the sections could be built by any reasonably equipped metal works and not necessarily in a dockyard. It also meant repair work could often be carried out swiftly, here a new bow section is delivered to replace one damaged by collision.

Close attention was given to making the ship suitable for heavy weather in arctic regions, particularly around the bow where experience had shown ice was most likely to build up. The Bridge was also equipped with heated windscreens.

In order to try and improve performance at during Convoy operations Cruise Turbines were fitted in additional to the main Turbines. This was not innovative, the Cruise Turbine had been a feature of warship design since the outset, though more often associated with large ships. These were intended to give the Type 12 an efficient cruising speed of 12 knots to conserve fuel and engine wear. Sadly they did not work properly due to problems with the automatic clutch system and they were omitted in the following class and the pretence of being a Convoy Escort also, the Type 12(M) which would follow would be classed as a Fleet Escort.

On paper the Whitby had good anti aircraft defences with the twin 4.5" Mk6 radar guided automatic turret and a seperatly radar targeted twin 40mm tri-axially stabilised 40mm STAAG. A combination of medium range radar and height finder backed by an optical and radar director meant the high angle 4.5" could not only engage aircraft but also surface targets and provide Naval Gunfire Support to shore in all conditions.

Unfortuantly things were less than they appeared. The 4.5" Mk6 could not be operated in automatic loading mode, reducing it's rate of fire and requiring additional crew to man the ammunition feed. The STAAG also was so mechanically and electronically complex that it developed an unenviable reputation for breaking down and all would be withdrawn from service.

As the Class were intended for Atlantic work no provision had been given to keeping the ship cool, indeed, most of her design concentrated on avoiding the dangers of ice building up on the ship, hence the recessed anchors and the pronounced curve at the knuckle of hull and deck. Yet early in their career, with no actual convoys to shepherd, they found themselves in warmer climes, HMS Scarborough, despatched to Christmas Island as guard ship during the H Bomb trials, had to have a hasty refit on the way to provide fridges and fans, but her considerable fit of radar, sonar and radio, all crammed with glowing hot valves, the heat of foriegn stations proved detrimental to the operation of much of her equipment. All of the Class would end up spending much of their career as Dartmouth training ships closer to cooler climates.

Accomodation had been a factor in the design of the ship as with her sister aircraft defence ships, probably the first time ever for the RN! By modern standards it was still crude, but the right moves were being made, the crews had mess decks with room for hammocks for all (traditionally the newcomers to the ship would sling their hammocks wherever they could, even next to noisy machinary, and gradually work toward more comfortable surrounds as the crews rotated. Messing arrangements I cover elsewhere in greated detail but the Whitbys were also provided with extended galley facilities and at least the provision for a staff of professional cooks and caterers (though if actualy embarked in those early days I have no idea)

All of which may come over as a bit negative, but there was a lot of positive about the Whitby too, they proved sound ships in any weather, even better than their sisters as they had the longer forecastle. That fact alone made them valuable to the service. Their Ops Room compared with those fitted on capital ships of the time and the ships were enthusiastically acclaimed as the potent anti-submarine ships in the RN, and pershaps the world.

An unexpected bonus was the ability to provide electrical power while alongside as the ship has surplus with boilers and diesels running, making them ideal for dealing with disaster relief sites. Despite the disappointing performance of the cruise turbines the engine plant was robust and reliable.

Speaking to people who have served on them I get mixed reviews of the accomodation, older hands begrudged the loss of control (and probably the profit) of controlling their own catering but admit the sleeping and bathroom arrangements were a huge improvement. But a sour note from all was the Officers Quarters jumped up disproportionatly to resemble cruise ship accomodations.

HMS Scarborough which acted as guard ship during the H Bomb tests at Christmas Island

Retired from active service in the early 70s the ships either entered reserve or served as Trials or Training Ships.

Unlike the Rothesay class they were never extensively refitted, with the exception of Torquay which served as the CAAIS computer trials ship.

The design was welcomed by Australia and New Zealand who operated their own versions, and the Y-100 was adopted by the Canadian Navy for their own Escort Ships. The lack of a mid-life refit was odd, they even retained the outdated 275 radar equipped director which saw service during WWII. A clear line was drawn between the Type 12 and 12(M) which did go on to be extensively refitted to bring them close to the capability of the Type 12(I).

Changes in appearance during the life of the ships are mainly the alteration to the funnel which is made taller and raked back to deal with problems exhausting fumes and the torpedoes and STAAG removed. Once the STAAG is gone a small deckhouse is built astern and the mainmast mounted on top of it. In Torquay this is later extended aft to house the Ferranti CAAIS computer system for trials, removing the forward Limbo Mortar, the forward mast was also replaced with a solid type like those on the Leander and the refitted Rothesays.

HMS Blackpool would spend time with the New Zealand Navy, on loan for five years and actualy commissioned into the New Zealand Navy as HMNZS Blackpool from 1966 to 1971.

The failure to update the Whitby Class is something of a mystery to me, the Rothesay refits might have been expensive, but still much less than the cost of new ships. In the event they are mostly disposed of in the late 70s, coinciding with the introduction of the Type 21 Amazon Class Frigates, however when taken into account the disposal of the Type 41 and Type 61 at around the same time then less than half of the ships are actualy replaced. Around this time too the Type 14 Blackwoods and Type 81 Tribals are being phased out, though some of the Tribals will be reactivated during and after the Falklands frigate numbers will be hopelessly low when they are desperatly needed.

Whatever the reasons, by the late 60's the Rothesay Class have been refitted and the Whitby's left in a backwater awaiting the scrapyard.