Floating cranes are playing an increasingly important role in ship- to-ship and ship-to-shore bulk loading, unloading and transshipment of numerous cargoes. Because they require no port infrastructure, floating cranes are flexible and can operate within or outside of ports. The importance of floating cranes is particularly being driven by port charges and bulk carrier size. Higher port charges are generally causing operators to reconsider their loading and unloading operations, moving them away from the quayside. Larger bulk carriers and the resultant deeper draughts mean that the ports need to be deepened or the bulk carriers must lighten their cargoes before entering port. Due to their flexibility and high throughput capacity, NKM Noell’s lemniscate floating cranes are increasingly used in the Netherlands to unload grain but also to transship cargo from bulk carriers into barges for further shipment.

For handling light and free-flowing materials grabs are used with high enclosed shells to minimize material loss and environmental pollution. The grabs can be equipped with overlapping under knives to minimize spillage even further for the finest materials. The enclosed scales are minimizing the influence of the wind on the material inside the grab. The upper side of the scales are provided with steep plates that are open at the top. The advantage of the steep plates is that materials are not compressed against these plates that are open at the top.

The open upper side of the grab ensures the crane operator of a good view into the grab. By doing so he can check the filling of the grab.This is especially important during cleaning up.

In contrast with a crane designed as mobile crane in NKM Noell’s crane the operator has always and in any circumstances a direct view on the grab. The operator does not have a look at a screen to see into the hold. Also due to the lemniscate concept the rope sheaves at the top of the jib are a lot lower, the rope length is therefore shorter. This reduces grab

swinging. This both results in very short cycle times and high capacities. Especially during bad weather conditions (fog, rain) and during night time and joint operations with shovels in the hold. The excellent operator visibility results in a lower capacity drop in adverse conditions.

In general reliability, availability and the crane’s lifetime are key aspects in the design.

Essentially, the crane must be economical to operate and be environmentally friendly. In this respect, one optional design feature of the NKM Noell floating crane is the use of a flywheel to ‘charge’ the generator-sets located in the pontoon. The flywheel itself is ‘charged’ using regenerated energy from the movement of the grab.

This feature reduces energy consumption and smoke emissions.

PRINCIPLE DESIGN

The design of the advanced crane concept is derived from the classical lemniscate crane and incorporates the lessons learned from the above.

This has resulted in a crane design that includes: 

  • electrical drives, the NKMNoell lemniscates do not have hydraulic drives. The installed electrical drives need less
  • maintenance and are more reliable. Also an electric drive is more energy efficient than a hydraulic drive resulting in lower fuel consumption;
  • a strong and stiff steel structure; 

 

  • a low centre of gravity; 
  • redundancy in the slewing and luffing mechanisms; 
  • a fully balanced luffing system; 
  • optimized slewing speed; 
  • optimized luffing speed; 
  • PLC control; 
  • semi-automatic grab control; 
  • a comfortable cabin with sophisticated suspension and optimized view; 
  • a safe escape route (no need to enter the machinery room); 
  • low fuel consumption; 
  • low smoke emissions; 
  • low exhaust emissions; 
  • a minimum design life of 25 years; 
  • elevator access (optional); and 
  • use of flywheel (optional).

 

THE PRODUCT

Based on the principles described above, NKM Noell designs and builds cranes to customer specification. Each crane is tailored to the customer’s specific needs.

NKM Noell can also supply the pontoon on which the crane is installed and can arrange the installation. Life-time maintenance is available via a Service Level Agreement (SLA) and any delivery is backed by the comprehensive NKM Noell guarantee. Even though custom-built floating cranes are complex, NKM Noell’s continuous improvement approach is continually driving down delivery times.

NKM Noell Special Cranes GmbH is a leading supplier of special cranes and special handling equipment. In addition to advanced special cranes, it can also supply R&D, consulting, feasibility studies, design, engineering, manufacturing, shipping, installation, commissioning, training and after sales service.