Modern shipbuilder chooses laser measurement

Measurement specialist Hexagon Metrology describes how the surveying team at German yard Meyer Werft uses Leica Geosystems instruments to maintain build quality

of its cruise ships. By Andreas Petrosino.
According to the company, many sea miles travelled in some of the largest and most luxurious cruise vesels afloat owes a lot to a small town in Northern Germany. Papenburg in Emsland usually finds itself at the focus of interest only when a new ship runs down the slipway at Meyer Werft and moves with impressive precision along the river Ems into the North Sea. But similar – if not greater – precision is demanded in the fabrication halls.
The enormous ship fabrication halls at Meyer Werft are the temporary homes of ferries and gas tankers as well as cruise liners. New ships are put together from over 60 individual blocks, which can weigh up to 800 tonnes each. The quality of the connection interfaces plays an important role in the construction of the ship and in the assembly of the blocks themselves. Consistent measurements are crucial – correcting mistakes is virtually impossible.
Ralph Zimmermann, a qualified surveying engineer with over 20 years' experience, heads the surveying section at Meyer Werft. "Our surveying instruments are used every day under harsh conditions in both indoor and outdoor environments. In addition to the quality of the instruments, we also recognise the value of good service and a long-term relationship. It is important that our partners are still there for us tomorrow," says Zimmermann. "In Leica Geosystems and Hexagon Metrology, we have found partners who have never once disappointed us."
Involved in the action
The surveying team at Meyer Werft is on hand to provide its services at every stage in the production of a new ship. Alignment of the plasma torch cutting machines is one of the first tasks. Accuracy is also demanded when laying keels and fabricating the blocks. On top of this comes a host of other special jobs, such as determining the overall length of a ship. Zimmermann says: "More and more parts are being prefabricated and then attached to the ship in once piece. For us this means we have to carry out fairly accurate 3D surveys – such as taking the measurements of a sun shade composed of multiple concave shapes or a 260m-long waterslide with curves and loops."
The contents of the instrument locker at Meyer Werft include a Leica TDRA6000 laser station and two Leica HDS6200 high-definition surveying (HDS) laser scanners. Both instruments are permanently in use. Zimmermann explains: "The HDS scanners and laser station together form a strong combination. Before we begin to scan and capture point clouds, we determine the exact position of the targets using the Leica TDRA6000 and create a mesh. Most of the targets remain as fixed reference points, some are only temporary. We can then move the scanner from area to area and set it going immediately, because we always know where we are in the surveyed space. The process is pretty much like land surveying."
Competitive advantage
Zimmermann wishes to ensure that the high standard of Meyer ships will continue to be achieved in the future and actively promotes the training of young surveying engineers. Meyer Werft sees consistent quality as a key competitive advantage. For this reason Zimmermann has been upgrading surveying equipment and practices at the shipyard piece by piece – and always with Leica Geosystems and Hexagon Metrology firmly on board.