The Manitowoc 21000 is a truly interesting piece of heavy lifting machinery. It is billed as a 1,000 US ton crane, but it cannot actually lift that much without a few attachments, collectively known by Manitowoc as a ‘Max-er’ which increases its capacity from 754t to 907t (1,000 US ton).
The Max-er concept is the Manitowoc version of what other manufacturers call superlift, and is based on the addition of extra back mast behind the boom, and suspended counterweight on a trailing bogey to increase lifting capacity.
The 21000, with its distinctive ‘Octa-trac’ crawler track design, made its debut on site in August 1999 (Baptising the 21000 Oct99, p21) but it was not until October that it was seen in its maximum capacity configuration, i.e. with Max-er.
More recently, Manitowoc has also begun deliveries of a new Max-er attachment for its 2250 crawler crane, more than doubling the lifting capacity of its earlier attachment in parts of the chart.
A 21000 fitted with a Max-er attachment was used for the first time last October by Anthony Crane Rental at a chemical plant in Illinois, USA. The crane, in wide stance configuration and fitted with 79m of main boom, lifted a 41.5m high de-ethaniser tower which weighed 429t.
The Max-er version of the 21000 uses the same main boom as the base version but has a 42.7m back mast instead of the basic crane’s 30.5m. It also has the characteristic additional hanging counterweight.
To date, Manitowoc has shipped just two models of the 21000, the other being to All Erection, whose crane is pictured on the cover of this issue at a petroleum refinery in Kentucky lifting a 187t regenerator head (part of a process vessel), also back in October.
A third 21000, however, was at time of going to press in Manitowoc’s yard undergoing tests of a new luffing jib attachment. The luffing jib will offer the potential for reaches of 182.8m with the Max-er (91.4m main boom + 91.4m luffing jib) or 146.3m without the Max-er (54.9m main boom + 91.4m luffing jib). This crane will also be delivered to All Erection.
Manitowoc’s new Max-er 2000 attachment increases the capacity of the 2250 from a maximum 272t at 5.5m radius to 453t at 8.5m radius on its 36.6m minimum boom. More significantly, the new Max-er offers a maximum boom length of 109.7m with heavylift boom and 121.9m with long-reach boom.
The luffing jib offers a maximum capacity of 227t , which is achieved using a boom and jib combination of 42.7m + 21.3m. The maximum combination of boom and luffing jib is 91.4m + 61.0m, with which it can lift 38.2t at a 24m radius.
Adding a fixed jib on the end of the luffing jib gives a maximum possible reach of 189m (91.4m + 61.0m + 36.6m). In this configuration, capacities range from 6.8t at a minimum radius of 50.3m to 2.1t at 104m.
Manitowoc claims that the 2250 with Max-er 2000 can be erected in a single day. Major components include a heavier boom, a 39.6m back mast and backhitch, and a suspended trailing counterweight assembly, which is available with or without wheels.
The Max-er 2000 is designed to incorporate many boom, rigging and counterweight components from the basic 2250 crane. With “minor retrofitting” the Max-er 2000 can be used with 2250s already in the field, but it cannot be used on the earlier M250s, nor can old Max-er 225 or 400 attachments be upgraded.
Manitowoc says it has received more than 10 orders to date and has already delivered the first to a customer in North America (who asked for no publicity). The Max-er 2000 will be officially introduced to the market at the Intermat show in France in May.
