Artist impression of SK 90

Abnormal Load Engineering (ALE) will launch its new state-of-the-art multi-purpose lifting machine on 11 September at Breda, Netherlands.

The 4,300 ton capacity SK 90 crane is an ALE-patented design with the advantages of a long outreach and, like other heavy cranes, it slews by turning around a large modular ring that is set up outside its lower structure. However, unlike its rivals, it can operate with only a section of a complete ring assembled.

Miriam Schalken, spokesperson for ALE, says the company gave the concept a lot of thought over the years and wanted to get away from the ring idea.

"The system we have designed is referred to as the topping lift. It is four large hydraulic rams pulling on a plate link system and each stoke of the jack is 800 mm.

"We did not feel the strand jack arrangement is a good solution as the strand grippers collets often get clogged as the strand loses tension.

The crane has a maximum boom length of 148 metres (486 feet) for the main boom and 48 metres (157 feet) backmast. It lifts 600 tons with a winch with 10 parts of line.

The SK 90 raises a maximum load with 4,000 tons of counterweight and its maximum load-moment is 96,000 tm.

Schalken says the company decided to build this crane to enhance its position as a heavy-lift contractor in the petro-chemical construction industry, especially in the Middle East.

"The SK 90 has changed a lot of the thinking concerning construction techniques of new plants. There are many other applications where the capacity of the crane allows engineers to build more efficient process plant."

ALE has several versions of the crane that will take around 21 days to assemble and 18 days to disassemble.

The prototype is in the process of being assembled and testing will begin at the end of the month.