HMS Cumberland - Britain's first nuclear warship.Following the successful development of a reasonably compact and navalised nuclear reactor at the Dounreay research establishment in the late 1950s, a ship to utilise it,
HMS Cumberland, was laid down in 1960, commissioning in 1963. The design of the ship differed in a number of ways from the first ever nuclear warship, the
USS Long Beach. The US Navy had boldly opted for an all-nuclear powerplant, but the Royal Navy decided to be more conservative, so
Cumberland had a CONAS powerplant, a single reactor being paired with the same conventional steam plant as the County class destroyers in production at the same time. The uptakes for the boilers were lead into a "mack" (combined mast and stack: a first for the Royal Navy) in order to make best use of the centreline space freed up by the lack of funnels. Another difference was the adoption of electric, rather than mechanical drive, this being chosen in order to minimise the amount of steam piping in the ship and allow the reactor to be completely isolated should it have a problem.
The comparison with the County class destroyers was key, since one of the principal roles of the new ship was to evaluate nuclear versus conventional propulsion, together with a range of other tactical nad technical concepts. To this end, the ship was equipped with all the same systems as a County, but given the ship's size (more than twice as large) she was given more or larger versions of many of them, one of the arguments of the the nuclear proponents being that the increased size and cost of nuclear ships was compensated for by their increased fighting ability. Partly to reflect this, the ship was rated as a cruiser, and given the pennant number of the previous
HMS Cumberland which had been scrapped in 1958, having spent the latter part of her career, appropriately enough, as a trials ship.
As comissioned,
Cumberland had two twin 4.5" Mk.6 gun turrets in A and B positions, and a Limbo ASW mortar in a deckhouse in C position. Aft, a triple Seaslug SAM launcher and it's enormous magazine dominated the design.
Cumberland's size meant that she could carry two Type 901 fire control radars for this system, so the increased beam was used to carry two hangars for Wessex ASW helicopters on either side of the radars. A pair of Seacat short-range SAM systems sat on the hangar roofs, and the final layer of defence was provided by two 20mm Oerlikon guns just behind the bridge. By contrast, the Counties had a twin Seaslug launcher with only one type 901, a single Wessex housed in a very cramped and awkward hangar and no Limbo mortar.
Cumberland also carried the same enormous Type 984 3D radar as was being fitted to some, but not all, of the Royal Navy's carriers at the time, the intention being to analyse whether this unit was more effective when fitted to a carrier or one of it's escorts. Since the reliability of the Type 984 was suspect, a conventional Type 965 air search radar was also fitted.
HMS Cumberland spent much of the 1960s involved in trials and exercises designed to prove the safety and utility of her nuclear power and was judged to be very successful in this role. However some of her technology (notably the Seaslug missile system) was regarded as dated even before she commissioned and since the results of the trials had confirmed the reliability of nuclear power, it was decided that the follow-on nuclear cruisers would be built to a very different design, with all-nuclear power and the much more compact and capable Sea Dart missile system. However it was the end of the road for the British surface ship reactor programme, since the Americans had convinced the UK government of the economies of scale to be had from mass production of their D2G design, so the new Royal Navy cruisers would be based around two of these plants.
HMS Cumberland thus remained the sole example of her type.
That left the question of what to do with
Cumberland. With the trials phase of her life largly over, she was refitted for fleet duties in the 1970s along the same lines as the second batch of Counties, with improved radar and fire control systems, Exocet missiles in place of the Limbo, and STWS-1 torpedo tubes. Unlike the Counties however, the enormous cost of the ship made it unacceptable to government and public alike that she should be paid off early, and so, despite the obsolescence of her main weapon system, she soldiered on into the 1980s. She deployed to several trouble spots during this period, including Cyprus, the Falkland Islands and Lebanon, but of course, never fired her weapons in anger.
When the last County was sold off the Seaslug system became impossible to support so at that point she was refitted again, this time as a command and ASW cruiser, with an extended flight deck in place of the Seaslug, an enlarged hanger for four Sea king helicopters, and Sea Wolf point-defence SAMs. The original intention was to run her on into the 21st century in this fit, thus getting the forty years of service that was felt to be acceptable given her cost. However a further refit was cancelled in the early 1990s due to post-Cold War defence spending reductions, and cracks were then found in her reactor's primary cooling circuit which would be very expensive to repair, so she was swiftly taken out of service in 1996 and unceremoniously scrapped. However even at the end of her life
HMS Cumberland continued to serve, since she was was the first British nuclear ship to be decommissioned and many important lessons were learnt in the process.
The profile shows
HMS Cumberland in her original state of fit on her first commission.
Profile created by myself, based on a very good
HMS Kent profile by Shipbucket contributor "Hood".