30.06.2009

ALE clarification

Abnormal Load Engineering has pointed out some very valid flaws in our preview of the new 100,000 t/m Mammoet PTC120DS heavy lift crane.

As a final part of our preview we looked at how the new crane stacked up with the ALE heavy lift machines, the SK90 and its larger brother- yet to go into the iron – the SK120.
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The ALE SK90 in action

The comparison looked at the radius at which the Mammoet will lift 3,000 tonnes, 2,000 tonnes, 1,000 tonnes and 500 tonnes and compared it with the ALE load chart for its two big lifters.

ALE points out that as its machine does not have a regular slew ring it uses outreach, rather than radius. Given the way most lifts are planned a true side by side should adjust the chart to use the same measurement.
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The difference between radius and outreach, ALE to the left Mammoet to the right

The following is the adjusted comparison.

Radius - Outreach Mammoet – ALE ALE
metres metres PTC120 -- SK90--- SK120
48----------27.5---------3000 ---- 3152 --- 4518
54----------33.5---------2000 ----- 2793 -- 3750
98----------77.5---------1000 ----- 1005 -- 1682
122-------101.5----------500 ------ 573 -- 1079

This opens up an interesting area which we plan to cover in the next issue of Cranes&Access along with the letter from ALE. One thing is for sure, both the ALE and the Mammoet are highly impressive pieces of engineering.