Block-setting crane
This time also coincided with the availability of large-scale ironworking with which to build cranes, and portable steam power with which to drive them.
Their working area was along the length of the breakwater, which had not yet been constructed at the time that most of the heavy masonry was put into place.
To avoid this, they had to be anchored in position before each heavy lift, either by tying them down or by ballasting them to sit on the harbour bottom.
They also required the lowering of screw jacks onto the rail heads before they could lift, which limited their ability to move a load.
In 1869, Stothert and Pitt constructed their first dedicated block-setting crane, 'Parkes' Titan' for the Manora breakwater, Kurrachee harbour,[ii][3] This was to the design of William Parkes (1822-1889).
The completed breakwater was to be 24 feet square in section, comprising three courses of blocks, laid on 9000 tons of rubble, dumped as a foundation.
The projecting gantry of 23 feet allowed two courses of blocks to be laid before the whole crane had to be moved forwards.
It was powered by an 8 hp steam engine, on top of the gantry which, together with its water tank, acted as a counterweight.
Although railway steam cranes were becoming common at this time, they had lifting capacities only half this and needed to be blocked up first.
[2] Owing to a lack of local stone, the breakwater was built from concrete blocks, cast on site, using cement brought from England.
[5] In 1881, Stothert and Pitt constructed a horizontal jib crane for Sir John Coode's harbour building work on the Kowie River at Port Alfred in South Africa.
The lift capacity was 15 tons, and there was enough wire rope to allow the hook to descend 26 feet below rail level.
The ability to move blocks rapidly from the wagons bringing them, and to put them in place accurately, was better than any other crane types yet used for this work.
The kingpost was also placed further outboard, at the edge of the large ring bearing, making the most of the truss' span for increasing the reach of the jib.
Early examples were built by Stothert & Pitt for the Breakwater Crane Railway, Douglas Harbour, Isle of Man[7] and by Alexander Shanks & Son for Liepāja in Latvia, then part of Russia,[8] and a 50 ton crane for Roker Pier, Sunderland.
At Roker, a second separate Goliath (gantry) crane was provided at the rail head, for loading the granite blocks from the railway to the tramway along the pier.
These had a deep double truss as a cantilever beam atop a large diameter roller bearing, on a carriage similar to that of the Hercules.
The upper edges of the two trusses formed a set of rails for a moveable trolley carrying the lifting cable sheaves and hook.
Some of the Hercules type cranes, with a cable-stayed jib supported by a kingpost, were termed 'Titans', if they were capable of slewing in a full circle.
This only required new lines to be laid along the breakwater and a longer cable supplied to power one of the existing cranes, moved into position for this work.
They were dismantled for shipping and might even be designed to make this simpler, with bolted joints to break the crane down into components, each of which was permanently assembled by rivetting.
The steam plant and moving parts could be removed and re-used, whilst the large but relatively simple framework was scrapped in situ and a new one built for the new site.
They have appeared in instruction guides, as shop display models, and as one-off constructions by dedicated Meccanistes.
