<%@LANGUAGE="JAVASCRIPT" CODEPAGE="1252"%> Type 12(M) Rothesay Class Frigates


Type 12(M) Rothesay Class

Originally the Rothesay Class ships were announced as an extension to the six Type 12 ships already ordered. The naming convention remained the same for instance. The Admiralty announce that the ship's had been modified in layout in light of operational experience of the Type 12, but the modifications were not detailed and it was probably assumed at the time that the alteration of the funnel shape and changes to the torpedo tube layout summerised the modifications.

It was not until 1962 that Janes Fighting Ships began to segragate the first Type 12 batch from the second, listing them as Type 12 Modified, though without giving any reason other than the Admiralty spin of changes in layout.

In fact the main change is the embarrasing failure of the cruise turbine (or rather the clutch for it) which was to have given the ship the range required for a Convoy Escort. The ship is now classed as a Fleet Escort and the Cruise Turbines have been omitted from the engine rooms, though the fittings for it remain and the engine still has access ports built into it to receive the cruise turbine shafts. Provision has also been made for an additional 30 tons of fuel which marginaly improves the range of the ship, though still falling about 1,700 NM short of the original designed range.

Early in their life it was announced that they would be refitted to operate the Wessex Helicopter equipped with a dipping sonar, but following the deployment of the Wasp to the Type 12(I) Leander and the Type 81 Tribal class frigates the Type 12(M)'s were fitted for the Wasp instead.

As built there is very little to distinguish the Type 12(M) from the Type 12. The funnel is taller and raked, but that modification will be retro fitted to the Type 12s as well.

The positions of the fixed and trainable Anti-Submarine torpdeo tubes are reversed, probably as a result of experiences with the weather but that about sums up the outward appearance. Internaly the ships have air conditioning to electronic equipment rooms (and by all accounts to the officers cabins) and bunks are fitted to the junior rates messdecks, though hammocks are still in evidence until the mid-life refits. The failed Cruise Turbines have been ommitted and the ships re-classified as Fleet Escorts.

Twelve Type 12(M)s were ordered for the RN, which with the six Type 12s were to bring the anti-submarine First Rate Frigate strength up to eighteen, but the tenth, HMS Hastings, was delivered to New Zealand as the HMNZS Otago and another hull ordered to replace it, but work on the Hastings and the Weymouth and Fowey, the last three hulls, was stopped and they would be completed as the Type 12(I) Leander Class.

Right: spot the difference? Above HMS Tenby, Type 12, below HMS Falmouth, Type 12(M)

Those ships that were completed entered service in 1960 & 1961 and served in the strange twilight time, the Suez Crises had ended in bitter humiliation for Britain and her supposed staunch ally the USA had turned on her. Worse was to come, in just a few years Dennis Healey would deal the death blow to the Carrier Fleet. In the midst of it all new and vastly superior Soviet nuclear submarines were slipping deep into the oceans.

New technology pushed warship design into greater sizes. In order to maintain the equivilant weapon fit of a WWII Destroyer a post war destroyer began to approach the dimensions of a cruiser, likewise the Frigate became the new Destroyer sized ship, this despite abandoning the traditional redundancy in engine and boiler systems.

The Type 12 displaced more than twice as much as the Loch Class Frigate it was to replace and carried over a hundred more crew, yet their weapon fits are approximatly the same.

The disparity is caused by the increasing sophistication of radar, sonar and radio and the need to both man them and maintain them. The Type 12 combined large ship Tactical Systems with a relatively small and compact hull, a combination that commanders would find superb and combined with excellent sea keeping made the Type 12 the anti-submarine weapon of choice when she entered the Fleet.

HMS Falmouth as built

A scan of a postcard from the Plymouth Museum. This nicely shows the before and after configuration of the class, though the above shot is taken some time after build as the STAAG is removed and replaced with a deckhouse with the Mk VII Bofors mounted on it in lieu of Seacat.

The Rothesay Class are inextricably linked to the Leander and I will cover much of the reason for the changes there. But essentialy the Nuclear Submarine, starting with the K-19 that appeared at the same time as the Rothesays, were deemed to have made even the purpose built Type 12 Escorts obsolete, the argument being how could a ship hope to kill a submarine it could not catch?

The salvation was seen in the light helicopter then being developed for the Type 81 Tribal Class Frigate. The Leander Class were purpose designed for it and with some imagination and work it was perceived that the Rothesay Class could be retro-fitted (so could the Whitby, but for some reason was not).

Top hamper is always the issue in adding gear to ships, and particularly so in small ships designed to operate in the worst the fierce Atlantic could throw at them. Some of the changes made to the Leander were just too radical and expensive to contemplate: the re-siting of the diesel generators for instance would need a virtual rebuild from the keel up. Oddly enough one obvious solution was not taken up: the removal of the gun turret, in a ship whose primary role was still very much Anti-Submarine the failure to take that step would leave the Type 12(M) forever a poor cousin of the Leander.

HMS Berwick as modified. Note the Diesel fumes coming from the forcastle, at anchor the ships could alternatly rig short funnels on the forecastle.

Some weight was easily obtained with the removal of the STAAG and useless torpedo tubes. The loss of one of the Limbo Mortars to provide a flight deck and further weight saving was next. Extra weight was added in the form of the hanger, but there was no lee way left to extend the hanger forward as in the Leander and no provision for the heavy AKE aerial of the 965 air warning radar. Those could have been provided for the cost of the 4.5".

Provision was made for the lightweight optical version of Seacat, GWS-20, here again the sacrifice of the gun could have allowed a double headed system forward and aft.

In the event the finished result was a ship that simply sacrificed one Mortar for the greatly more effective Helicopter.

Internally the ship was brought up to standard with the Leander for messing. A central dining hall for ratings and all food preperation now centralised in a dedicated galley. All personal now had bunks which folded to form mess seating, stabelisers were fitted to improve the stability of the ships as an aircraft platform and also served indirectly to improve the lot of the sailors.

In some ways the Rothesay would not match the Leander, the Operations Room was particularly cramped and there was no space available for a computer system which the Leanders would get in later life for instance, but on the whole the refits extended the lives of the ships, making them Operationally sound again and they would prove an asset to the Fleet for many years yet. This ability of the Type 12 to adapt so readily was not lost on foreign navies and did much to boost exports.

Understandably some mistake the M for Modified in the Rothesay Class as referring to the changes which were actualy made a few years after their commissioning, they always bore the Classification of Type 12 modified though. Both masts were replaced with solid versions, the main mast now mounting the Seacat GWS-20 Director. The 6M gun director is replaced with the MRS-3 gun director which largely negates the need for the height finding radar since the MRS-3 needs only a bearing to swing onto and will conduct it's own height finding operations.

20mm Oerlikons are mounted either side and abaft the Bridge, these are not regarded as anti-aircraft weapons, but as weapons for police duties, "Junk Bashing" as the crews term it.

If any big brother condescension ever existed between Leander and Rothesay crews it was decidedly stamped on in 1982 when HMS Plymouth and HMS Yarmouth (The Crazy Y) put their mark on the Battle of the Falklands, surviving air attacks, shooting down enemy aircraft, disabling a submarine, bombarding shore positions and going to the aid of stricken newer ships.

HMS Brighton post refit. The value of aircraft in attacking submarines had been shown very clearly in WWII (and WW1). The Americans had experimented with unmanned helicopters without much success but with the advent of the light Wasp Helicopter and the Mk 44 Anti-Submarine homing torpedo the capability of the Type 12 was suddenly increased.

If I seem at times to make a point of the disparity between officer and ratings accomodation I have I think very good reason. HMS Plymouth survived for a while as a museum, though at the time of writing this her future fate is uncertain.

I have two sons, one boy was only just born and the other too young to remember visiting his Dad's ships when I left the RN in 1994. In 2006 I took them both to visit the Plymouth in Birkenhead, at that time my eldest was taking his final exams and being courted by the RN for the Fleet Air Arm as a possible pilot.

Both boys were hugely amused at the folding bunks in the junior rates mess decks and I got them to picture conditions at sea. As we continued the tour we came to the officers quarters and both were loudly outraged at the difference in living conditions, particuarly when they also saw the wardroom and I explained the duties of the Stewards. My eldest rejected the RN from that moment, deeply offended at the idea he should accept such privalages when the "rankers" lived so. He joined the army soon afterwards and will probably one day fly the Apache rather than the Lynx.

Shown right, a junior ratings bunk space on HMS Plymouth, as built each mess had a precious few bunks and most crew slung hammocks still, these mess decks were for sleeping, recreation and eating. After refit all messes were equipped with bunks that folded to form seating arrangements and a seperate dining area was provided. Although a big improvement on living conditions known previously the lot of the lower deck sailor was still cramped and did not compare even closely to the comfortable cabins and wardroom of the Officers.

It says much that the lower deck accomodation on these post war Frigates was considered greatly superior to previous classes of ships!

Laid Down
F107 Rothesay 6-11-1956 9-12-1957 23-4-1960 Yarrow Scrapped 1988
F108 Londonderry 15-11-1956 20-5-1958 18-10-1961 J S White Sunk as target 1988
F106 Brighton 23-7-1957 30-10-1959 29-9-1961 Yarrow Scrapped 1985
F101 Yarmouth 29-11-1957 23-3-1959 26-3-1960 John Brown Sunk as target 1987
F113 Falmouth 23-11-1957 15-12-1959 25-7-1961 Swan Hunter Scrapped 1988
F129 Rhyl 29-1-1958 23-4-1959 31-10-1960 HMD Devonport Sunk as target 1985
F103 Lowestoft 19-6-1958 19-6-1960 26-9-1961 Alex Stephens Sunk as target 1986
F115 Berwick 16-6-1958 15-12-1959 1-6-1961 Harland & Wolff Sunk as target 1986
F126 Plymouth 1-7-1958 20-7-1959 11-5-1961 HMD Devonport Paid off 1988, museum at Birkenhead until 2006, current fate awaiting decision.
Figures given are post refit, pre-refit specs are the same as for Whitby Class with the exception of Range.
Displacement 2,380 tons standard, 2,800 full load
Length 360 ft waterline, 370 ft overall
Beam 41 ft
Draught 17ft 3"
Propulsion 2 Shafts, Y-100 engine fit comprising two English Electric 2 dual reduction geared turbines with reverse, 2 Babcock and Wilcox 550psi boilers generating 30,000 SHP
Speed and Range Max speed 30 knots, Range never made public but probably 3,500 NM at 15 knots with her 400 tons of oil
Armament Twin 4.5" guns on a single Mk VI turret
1 x quad Seacat GWS-20 AA missiles
1 x triple barrel Limbo Anti-Submarine Mortars
Radar Type 993 Target Indication
Type 903 Fire Control on Type GWS-3 Gun Director
Type 978 Navigation with RRA Helo Tracker (Later 1006 with RRB)
1 010/1011 IFF
Sonar Type 174 Search
Type 162 Bottom Search
Type 170 Limbo Attack
Aux Power 2 x Paxman 12YHAXZ diesels, rated 300 bhp at 900 rpm.(Intercooled version of those fitted to Type 12)

Westland Wasp HAS Mk1
Mk 44 or Mk 46 torpedoes
Depth Charges
Nuclear Depth Bomb
AS11 or AS12 Air to Surface missiles.

The Operations Room was a feature of the post war frigates, first trialed in the Type 15. This placed the Command Team below the Bridge along with the radar and sonar operators. Seen here is part of the Sonar display system in HMS Plymouth's Operations Room.

It might look as though it is made from bits of string and scrap metal, but the Wasp could pack a deadly punch, pictured here the "Budgie" is carrying a Mk 44 homing torpedo and a Depth Charge. The rear compartment could take a casualty, three men or mount machine guns.

Traditional Desstroyer design did not allow sufficient space for modern equipment in a small hull so compromises had to be made both in engine design and hull form to increase interior space. Seen here on the left is part of the 993 target indication radar, in the centre is fairly simple radar display (JDA I think?), others would include plotting electronics. On the right is part of the distribution system for the radar image which would be sent to the Operations Room.

HMS Plymouth, together with HMS Yarmouth served in the Falklands war with distinction in 1982, though in warship terms they were both old aged pensioners by then!