Arrol Gantry

The Arrol Gantry was a large steel structure built by Sir William Arrol & Co. at the Harland and Wolff shipyard in Belfast, Northern Ireland. It was built to act as overhead cranes for the building of the three Olympic-class liners.

Beardmore's gantry at Dalmuir

From 1900 to 1906, Arrol had constructed a shipyard for William Beardmore and Company at Dalmuir on the Clyde. This included a large gantry structure over the building berth. In 1906 it was used for the construction of the pre-dreadnought battleship HMS Agamemnon, then the largest battleship launched on the Clyde.[1]

The Beardmore gantry was 750 ft (230 m) long, 135 ft (41 m) wide and 150 ft (46 m) high, spanning a single building berth. The structure was of two long steel truss girders, supported on ten pairs of steel truss towers, braced by cross trusses above. Nine electric cranes were provided, with four jib cranes along each side girder, each having a 5 ton capacity and 30 foot jib. These were travelling cranes and could be moved along the girder, or grouped together to share a heavier lift. They were intended to place the main hull plates into position, with a dedicated gang for each crane, forming the plates and riveting them into place. A central 15 ton travelling gantry crane was also provided, for lifting machinery along the centreline of the hull.[1]

The Belfast gantry would be very similar to this first gantry, although larger at 840 ft (260 m) long and spanning two building berths. The central girder between the berths allowed the addition of a larger cantilever crane.[2]

The Beardmore gantry had used tapered towers, with size and strength proportional to the load upon them. The base of each was spread into a triangular arch, giving a more stable base and also allowing a railway line to be laid through the towers, bringing constructuion materials. For the Belfast gantry, the towers because more parallel, with straight inner faces. This allowed temporary working platforms to be attached and relocated upwards as a hull was constructed, giving an additional working space and easy access to the outside of the hull, even with heavy equipment. The access within the gantry was also improved, with long sloping walkways and electric lifts, rather than the previous slow and hazardous use of ladders.[1][2]

Construction

The Belfast gantry was commissioned the White Star Line[3] and Harland and Wolff and built by Sir William Arrol & Co. in 1908.[4] It was 840 feet (260 m) feet long, 270 feet (82 m) feet wide and 228 feet (69 m) feet high.[4][5] It was an essential part of the infrastructure needed for the construction of RMS Titanic and RMS Olympic and remained in use until it was demolished in the 1960s to create space for storage and car parking.[6]

Before the Gantry, the northern end of the Queen's Island shipyard had four building slipways, each with gantry cranes above them. The cranes formed three crosswise gantries over each slip, with jib cranes working from each upright. To make space for the two new slipways, three of the old slipways were given up. No 1 slipway remained and continued in use, with its original gantries, and was used for building liners such as the SS Belgenland. The two new slipways were numbered 2 & 3. There were nine slipways at Queen's Island before this, eight afterwards but the other remained numbered as 5...9 and there was no longer a No 4 slipway.[7]

Lengthwise elevation of the Gantry
Crosswise section of the Gantry

The Gantry was built on three rows, 120 feet (37 m) apart, of eleven steel truss towers with three large truss girders between them, and lighter crosswise Warren trusses above this. The large girders provided runways for a pair of 10 ton overhead cranes above each way and lighter 5 ton jib cranes from the sides. Along the centre line ran a light Titan crane, with a reach of 135 feet and able to carry a 3-ton load at full radius, 5 ton closer in. The cranes were electrically-powered and built by Stothert & Pitt of Bath.[5] Access to the high girders was provided by three long ramps and also electric lifts for the shipyard workers.[8] As Harland and Wolff were primarily a commercial yard,[9][lower-roman 2] there was no need for the huge Titan cranes being built at this time for the naval shipyards of the Clyde, where heavy lifts of armour plate, or even entire turrets, were needed.[lower-roman 3]

Olympic-class liners

Olympic and Titanic were built together, with Olympic in the No 2 slipway.[11][lower-roman 4][lower-roman 5] Olympic was launched first, in October 1910, with Titanic seven months later. To provide better photographs against the steelwork of the gantry, Olympic's hull was painted white during building, then repainted after launch. Titanic was painted in White Star's black hull livery from the outset. Britannic was then built on the Olympic ways.[12]

World War I

At the outbreak of World War I, Harland and Wolff were still engaged in building passenger liners and the Belgian Red Star Line's[lower-roman 6] 27,000 ton SS Belgenland was almost completed on the adjacent No 1 way. SS Statendam had been launched from the No 2 way in July, a fortnight before the outbreak of war. A further liner of 35,000 tons had been laid down there, but work had hardly started.[13]

When the Royal Navy wished to build the 14 inch monitors as coastal bombardment ships, these building ways were the most immediately available. The monitors were fairly small, of around 6,000 tons and quite short, but they also had protective anti-torpedo bulges which gave them an extremely broad beam of 90 feet (27 m). This would require equally wide building slips, which the Olympic slips could provide. The monitors were so short that the first two of them, Admiral Farragut and General Grant, could be built simultaneously on the same slipway.[lower-roman 7] Farragut was launched on the 15 April 1915, with Grant following on the 29 April. The limited lifting capacity of the gantry's cranes required the 4 inch armour plate to be installed in particularly small pieces, compared to in a warship building yard. To install their US-supplied turrets, the hulls were taken to the COW yard on the Clyde.[13]

Disuse

The Gantry was in use into the 1960s, but the shipyard was then reorganised to provide a larger building space. Work on large ships then took place in a large dry dock at the end of the Musgrave channel on the south-eastern side of Queen's Island, served by a pair of Goliath cranes, Samson and Goliath.[14]

A gallery at Titanic Belfast is dominated by a steel scaffold which stands 20 metres (66 ft) high and alludes to the Arrol Gantry: however, the original gantry was nearly four times the height of the gallery's representation.[15]

The Gantry dominated the skyline of Belfast and became an important local landmark, as Samson and Goliath would do again fifty years later. The poet Louis MacNeice's autobiographical poem Carrickfergus describes his birthplace:

"I was born in Belfast between the mountain and the gantries
  To the hooting of lost sirens and the clang of trams:"

This is somewhat anachronistic, as MacNeice was born just before the construction of the Gantry and his family had moved to nearby Carrickfergus before Olympic's launch.[16]

Notes

  1. The photograph caption is incorrect
  2. This changed later, with the acquisition of H&W's Clydeside yards.
  3. This changed under the pressures of WWI, and the 'large, light cruiser' HMS Glorious would later be built here.[10]
  4. No 3 way, used for Titanic, was the eastern building way, nearest to the Lagan. Looking forwards from on board the ships, this was the right-hand / starboard side way.
  5. As usual, the ships were launched stern-first
  6. Although Red Star was a Belgian shipping line with their home port in Antwerp, both Red Star and White Star were owned by J. P. Morgan's IMM.
  7. The monitors were initially named after US generals, in honour of the US source for their guns. However the neutral US was politically embarassed by this and so they were renamed to a simple M1...M4 after launch, then later to Abercrombie and Havelock[13]

References

  1. "Examples of Structural Steel Work for the Following Firms". William Beardmore and Company Ltd., Dalmuir. Bridges, Structural Steel Work and Mechanical Engineering Productions. Sir William Arrol/Engineering Ltd. 1909. pp. 150–158.
  2. (Arrol 1909, pp. 160a–160d, Shipbuilding Berth Equipment at Belfast)
  3. "Arroll Gantry". Sir William Arrol. Retrieved 16 October 2019.
  4. "The giant Arrol Gantry". National Museums Northern Ireland. Retrieved 16 October 2019.
  5. "Visits to Works (Excursions) in the Belfast area". 1912 Institution of Mechanical Engineers: Visits to Works. July 1912.
  6. "Arrol Gantry Fragment". Titanic Relics. Retrieved 16 October 2019.
  7. "2: Harland & Wolff – Fig. 3: Plan of the Queen's Island Works". The Shipbuilder (Special Number): 7. Summer 1911 via Archive.org.
  8. "Design & Build" (PDF). National Museums Northern Ireland. Retrieved 16 October 2019.
  9. Lynch, John (1999). "Technology, Labour, and the Growth of Belfast Shipbuilding". Saothar. 24: 3. JSTOR 23198888.
  10. Buxton (1978), p. 47.
  11. "Olympic".
  12. Piouffre, Gérard (2009). Le Titanic ne répond plus (in French). Larousse. p. 307. ISBN 978-2-263-02799-4.
  13. Buxton, Ian (2008) [1978]. Big Gun Monitors. Seaforth Publishing. pp. 17–21. ISBN 978-1-84415-719-8.
  14. "Belfast's Giants". Dennis Kennedy. Retrieved 16 October 2019.
  15. Choat, Isabel (6 September 2016). "Take the kids to … Titanic Belfast". The Guardian. Retrieved 16 October 2019.
  16. "Louis MacNeice". Poetry Foundation. Retrieved 21 October 2019.

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