Osprey lifts catamaran
By Christian Shelton18 February 2019
UK onshore and offshore transportation and lifting specialist Osprey used two Goldhofer SPMTs, a 1,000 tonne capacity Liebherr LTM1800D cable suspended telescopic crane, and a Modulift spreader beam to lift a 72.5 t catamaran on the Isle of Wight, UK.
Osprey was commissioned by shipbuilder Wight Shipyard to move the vessel from the shed in which it was built to the water at Venture Quays, Cowes. The 250-passenger Twin City Liner is 39.7 metres long, 11.1 m wide, and 6.8 m high.
To move the catamaran out of the shed, Osprey selected two, six-axle Goldhofer self-propelled modular transporters (SPMT) working in tandem to move the load to within the reach of the Liebherr LTM1800D. Osprey, in conjunction with long-term partner Allelys Heavy Haulage, claims to have one of the largest fleets of SPMT in the UK.The LTM1800D is a used crane that Osprey acquired in 2016 and had fully refurbished.
The crane was setup with a 36 m high rig, designed to accommodate a 3.7 m centre of gravity offset and different elevations of the boat’s lifting eyes. A Modulift MOD400 spreader beam was used at a 29 m span beneath 29 m long and 26.4 m long top slings to balance the lift. Two MOD70H beams were used underneath – one at 5.5 m long and the other at 4 m. Two different lengths of sling were used to connect them to the top beam:at the stern of the vessel it was 3 m and at the bow it was 3.9 m. The slings that met the lifting eyes at the bottom of the rig were all 4 m in length.
“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,” explained Danny Skidmore, heavy cranes manager at Osprey. “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.”
Osprey consulted spreader beam manufacturer Modulift and UK-based lifting equipment sales and rental firm FLG Services, which provided the rigging gear, on utilisation of the MOD400 at 29 m, as it usually has a maximum span of 24 m. Sue Spencer, technical director at Modulift, said: “It was more cost effective and convenient for Osprey to source the beam from a rental partner versus a custom designed product. Our technical team looked into the feasibility and came up with a solution whereby a central support sling system would be required to support the self-weight of the main spreader beam to minimise any potential deflection — and this adjustable sling system would need to be attached vertically to the crane hook.
“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, with the means to adjust the tension by way of a chain block. The customer monitored the tension throughout the lift to ensure that it did not go outside specified parameters. We attended the lift on an advisory basis to make sure everything went smoothly. 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.”