The introduction of the Cambria, and her sister the Hibernia, finally completed an earlier proposal to replace the 1920-built ships of the same name with two turbine steamers from the Clyde yard of Fairfield Shipbuilding & Engineering Co., Ltd., an order subsequently cancelled due to the onset of war. After the War, BR turned to Harland & Wolff Ltd at Belfast for the two new ships and the first of these, the Hibernia, arrived in Holyhead for the first time to a considerable welcome from locals and dignitaries, including Lady Megan Lloyd George on 5th April 1949.
The engine rooms of the Cambria and the Hibernia were very compact. At the forward end in a recess were two electrically driven air compressors. Also grouped at the forward end were the boilers, one to port and one to starboard, the three lubricating oil pumps, which also circulated the cooling oil, the three main sea-water circulating pumps and the two fresh water coolers, horizontally arranged. On each side, also forward, was a purified fuel tank and a settling tank.
In the wings of the engine room, in addition to the generating plant, were various pumps mainly for ship's service. These included the two general service pumps, an oily bilge separator, sanitary pumps, two sea-water circulating pumps and two fresh water circulating pumps. There were also two large-type De Laval separators, one to deal with lubricating oil, the other for fuel oil, each in association with a heater.
Forward of the engine room were three large fuel tanks. Aft of the engine room were two tanks to carry either fuel or water ballast.
Both ships were fitted with a new Harland and Wolff engine design; a trunk-piston two-stroke single acting unit. The two eight cylinder engines each had a cylinder diameter of 530mm whilst the main piston stroke was 820mm. The stroke of the exhaust pistons was 360mm, giving a total of 1,180mm. The exhaust vales were the same diameter as the cylinder, so no cylinder covers were required. At 231rpm the output of each engine was 5,000shp, the rating at 250 rpm being 5,500bhp. For the cooling of both the main and exhaust pistons lubricating oil was employed. Each cylinder had two fuel valves and one starting valve, in addition to a safety device.
The control position was located on the upper platform and manoeuvring was effected by means of two levers, one of which was for astern and the other for starting and speed control. There was a gauge board at each control station with a revolution indicator. There were also two revolution indicators at the forward end of the engines, visible from most points on the upper grating.
Well over 500 tons of fuel oil could be carried and as the consumption for a round trip was about ten tons the need for refuelling was infrequent. This figure compared with about 70 tons of coal for the round trip with a corresponding steamer. Running at 90% power a speed of 21 knots was maintained. Diesel was chosen over the tried and trusted steam as both ships would spend a considerable amount of time in port on their overnight workings. With a steamer, steam had to be maintained and this was considered a disadvantage as it not only cost more but also reduced time for maintenance work.
Two diesel generators were located on each side of the engine room and these each comprised a Harland engine driving a 200kW 220 volt genset. These engines were of four stroke design with eight cylinders, 250mm in diameter, the piston stroke being 300mm.
For protection against fire a Kidde Rich system was used, fitted in conjunction with CO² for the cargo holds and a Grinnell automatic sprinkler system for the passenger spaces and crew accommodation. Eight 28ft motor lifeboats were carried under gravity davits.
During the winter of 1964/65 the Cambria underwent major modernisation to bring her into line with the modern British Rail fleet. The distinctive early post-war style of interior was swept away to be replaced by modern aircraft type seats which gave a greater suitability for both day and night operations. The number of sleeping berths was thus reduced from 436 to 357.
The machinery also received attention. In search of maximum reliability the original engine rating of 500bhp at 231rpm was reduced to 180rpm with a corresponding reduction in speed from 21 knots to 18 knots. This is not to say the ships were unreliable, in fact quite the opposite and the only trouble throughout their careers was in way of an occasional cracked piston or liners; and this was normally due to the large number of manoeuvers employed.
To meet the requirements of more intensive running a Ruston Paxman 6RPHCZ 200kW generator was installed. This was placed forward on the port side of the engine room in place of one of the two electrically driven air compressors which was moved into the shaft tunnel.
Throughout her career the Cambria rarely strayed from the route for which she was built. She did however see service between Heysham and Belfast in 1969. But it was the Britannia Bridge fire on 23rd May 1970 that forced a prolonged removal from her usual routine. Robert Stephenson's bridge across the Menai Strait, which had stood for 120 years, was virtually destroyed in a single night, servering Anglesey's rail link with the mainland.
With no way of connecting the mailboats it was decided to transfer the mail service from Holyhead to Heysham. With an extended crossing time of 7½ hours the Cambria and the Hibernia continued to sail to and from Dun Laoghaire until 31st January 1972. With the first sailing back into Holyhead the Cambria was greeted just after midnight by a fireworks display and seemed like the whole town lining the quays to witness the event of that cold winter night. Despite their years, the Hibernia and the Cambria were still the pride of Holyhead.
The end of the time honoured mail service came in 1975 and it fell to the Cambria to take the last mail service out of Dun Laoghaire on Sunday 7th September. On the following day she stood down and the Holyhead Ferry 1 launched the new year round multi-purpose operation. Under the command of Captain Ivor Griffiths, with Glynne pritchard as 2nd mate, the Cambria slipped out of Holyhead for the final time at 23:00hrs on 28th October 1975. She arrived at Barrow at 09:00hrs the following morning for lay-up pending sale.
The Cambria remained at Barrow until sold to Orri Navigation of Saudi Arabia in January 1976 for a new career on the Red Sea. Renamed Altaif this fine ship sank while at anchor in Suez Roads in January 1981.