Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
P.R. Doorn Developments in the area of floating cranes
Literature survey, Report 2005.TL.7007, Transport Engineering and Logistics.
Floating cranes are found in most ports and are an important part of the handling equipment of the port. They have a special role in loading and unloading of especially heavy or awkward loads on and off ships, and besides that, floating cranes are used for transshipment activities, the transport of infrastructure (bridges) and for the salving of ships. Floating cranes can also be used when the quay is not strong enough for certain loads or when there is no quay (and thus no crane) available. Floating cranes can be self propelled (if not, tug boats are used).
Roughly speaking, there are more or less three kinds of floating crane types. The first one is the floating grab crane. The crane on the pontoon is in most cases a lemniscate crane and this type of floating crane is used for the transshipment of iron ore and coal from large bulk vessels into barges.
The next group is the so called hook duty floating crane (also called heavy load floating crane). The crane for this type of floating crane is usually a single boom crane or a shear leg frame. The difference between these two types of crane is that the single boom can make a full rotation (3600) in most cases and the shear leg cannot do this. The hook duty floating cranes are used for all kinds of jobs, varying from the placement of awkward loads on ships to small salving activities.
The last group is the extreme engineering floating cranes. This type of floating crane is used for extreme engineering jobs; the transport and placement of very large pieces of bridges and salving of big vessels.
Floating cranes have existed for a long time. In the 20th century the floating crane has been used for different purposes. When the mechanization started halfway the 20th century, the dry bulk handling was mainly done with a crane on the ship or on the shore, but when the vessels become larger and larger, floating cranes were used for the handling of the cargo. Direct transshipment from the vessel into barges was the way the cargo was handled, and floating cranes were the main equipment used for this.
In the '60's the vessels increased further in size and, as the floating cranes were not fast enough to handle these ships in time, the handling of these ships was done by quay cranes (indirect transshipment).
Nowadays, the ships still increase further in size. The ships have become larger, wider and deeper. Especially the increased draught of these ships makes it for some ports not possible to handle them in the port because the depth of the harbor is not sufficient. Before those ships can enter these ports, first a part of the cargo has to be transshipped (with floating cranes again).
Another development at this moment is that the vessels with containers have such a huge number of containers, that the existing quay cranes are not capable to handle these container vessels fast enough. A floating (container) crane can perhaps be a solution to this problem. The berth capacity could be increased by means of the floating container cranes which can handle the containers at the seaside. This concept is still in developing, but in the future this might just be another application of floating cranes.
Reports on Transport Engineering and Logistics (in Dutch)
