Starfish Ii

Right: It remains to be seen how the machine copes with salt-water corrosion. Extra-thick paint and corrosion-proof bolts are designed to help. Bottom Left: The counterweight spends much of its time underwater; a repositioned rear-view CCTV camera is used to keep an eye on it.

“Its most striking feature is without doubt the fact that the complete upper-structure has been lifted off the slew ring”

Bottom Right: With temperatures soaring well into the 40 degrees C the heavy-duty air-conditioning and anti-reflex glass package is no luxury.

machine have been kept to the bottom half of the unit. All the two hydraulic cylinders have to do is raise the 35-tonne upper-structure containing the engine, cab etc. The Belgian dealer is quick to point out that the extra length and width of the undercarriage are so engineered that stability is assured even when working on uneven surfaces.

Seabed

Developed for the international dredging concern Jan de Nul, this ‘starfish’ features a hydraulicallyraised upper-structure. Below, Left to Right: The modified excavator can work in 5m of water and has a maximum working depth of 8.87m when fitted with a 4cu.m bucket.

94 EARTHMOVERS MAY 2008

machines through the Belgian dealer. It is not every day that you come across an excavator that is capable of working under water. Its most striking feature is without doubt the fact that the complete upper-structure has been lifted off the slew ring. Instead, a new base plate has been fitted to the upper side of the slew ring. This houses the scissor-like construction, which is connected to a new base plate on the underside of the upper-

structure. Two hydraulic rams are employed to raise the complete upper-structure by a maximum of 5m. Of course, one of the first questions that springs to mind is stability, especially when you consider that the standard counterweight, which is fixed to the lower structure, is likely to spend much of its time under water. Not so, says Werner Hellemans of the Belgian dealer. This is because all the heavy parts of the

Although the undercarriage is from the ZX 870LCH, it has been lengthened and strengthened by Dutch firm STC to such an extent that it is now similar to that of a larger EX1200. When you consider that the tracks have been extended by 2m and widened to produce an overall machine track width of 5.60m, then it is clear that much of the weight of the 120-tonne machine is kept as close to the seabed as possible. The result is a machine that is capable of operating to a maximum working depth of 8.87m. When fitted with the standard 4cu.m bucket, it has a breakout force of 48 tonnes. One of the big questions is salt-water damage, an issue that the Belgian dealer seems to have sorted. For example, special bolts are used to secure the slew ring, as is a special grease that is able to withstand salt water. What’s more, although the finish of the machine looks as if it has been painted by an amateur, the extra thick paint, which comes from the industrial shipping sector, is essential. Another question is operator visibility of the boom and bucket. Initial feedback from the operator seems to suggest no problem, although it does take a day or so to get used to it, as he is totally reliant on the GPS system. We are told that special GPS software has been developed for the machine by Jan de Nul. As with any new machine there have been one or two teething problems, and Luyckx makes no secret of the fact that a few changes will be made if a second machine is made. However, the clear message is that the concept works, and competitive dredging contractors are all reported to be following the project with great interest. Furthermore, it is not just in Belgium that the machine is attracting attention, as a Dutch construction machine website has already recorded well in excess of 5000 hits. Many are keen to know how much the machine costs. Although there is nothing official, we reckon that the conversion quite likely doubles the price of the standard ZX 870LCH. Finally, although the operator is provided with a

life vest, bearing in mind the cost of the machine then he really wants to remain in the seat. However, just imagine that there is an engine failure as the water level continues to rise. A second emergency 100hp engine is included especially for such an event, to allow the operator to manoeuvre the machine into shallower water. This engine is also used to power the air compressor that is used to blow extra air at the

chisel of the hydraulic hammer (when used) to avoid water coming into the body of the hammer while working under sea level. Although the final decision has yet to be made, Luyckx and Jan de Nul are currently discussing the possibility of a second model. If it goes ahead then it is quite likely that a larger EX1200 could form the basis of the next conversion

MAY 2008 EARTHMOVERS 95