A Southampton firm which specialises in moving and lifting abnormal loads were moving into uncharted waters when asked to lift a 72 tonne catamaran.

Osprey Ltd moved the vessel from the shed at Wight Shipyard into the water at Venture Quays, Cowes before the ship left for its final destination – Vienna, Austria.

The 250-passenger Twin City Liner is 39.7m long, 11.1m wide, and 6.8m high.

Danny Skidmore, heavy cranes manager at Osprey, said: “We had to work closely with shipbuilders and naval architects, and refer to CAD [computer-aided design], to devise a method of lifting the catamaran safely and completely level.

"The previous time we lifted such a vessel, we used two cranes in tandem, but mobilising two cranes of that size represents a large-scale operation and high costs, not to mention the disruption it has on the shipyard. We wanted to come up with a way to minimise mobilisation and limit the impact on our client’s busy, marine environment.”

The big lift was accomplished using a 1,000t capacity Liebherr mobile crane and a below-the-hook rig, including spreader beams and a special sling devised by Poole-based Modulift. The rigging gear was sourced from FLG Services.

Sue Spencer, technical director at Modulift, said : "We devised a design whereby the tension load in the central sling could be monitored using a wireless load link to ensure that the sling was carrying the correct share of the self-weight of the beam throughout the lift>"

"We have not undertaken this type of rig before, and now we will be able to market our MOD250s and 400s at longer spans with a central support.”