WORK IS to start on a rare hydraulic shiplift in Dubai later this summer after contractors put in bids in July.
The $22M lift for client Dubai Drydocks is believed to be only the second of its type, said Stuart White, project manager with designer Royal Haskoning. The only other is in Portugal.
Dubai Drydocks is ordering the lift to enable construction of huge 360m long by 60m wide oil storage ships, which are increasingly being moored on offshore oil fields as tanks.
Such ships are conventionally built on a slipway and launched by sliding them into the sea. But Dubai Drydocks is opting for the hydraulic lift because it will be cheaper to construct and maintain, said White.
The lift will comprise a 14m deep basin adjoining the fabrication yard, which is 5m above sea level. The whole complex will measure 130m by 130m. Basin and fabrication yard will be surrounded by a 5m high sheet piled and mass concrete water retaining wall.
Dubai Drydocks will build 120m long ship sections within the fabrication yard in the dry.
When a ship section is to be launched an enormous steel caisson gate will be closed across the basin entrance and the water level raised until the ship sections float.
Once afloat they will be manoeuvred into the basin, before the water level is lowered again. Sections will then be floated out and on to a drydock for assembly.
Dock floors and sills will be mass concrete. White said the design calls for an unusually robust caisson gate, measuring 65m long by 16m tall and 8m deep, and weighing 1,400t.