SPS Sandwich Plate System Keeping High and Dry
Using the Sandwich Plate System, BASF is working to revolutionize shipbuilding, by replacing the conventional steel construction, with just two steel plates filled with liquid polyurethane, reducing corrosion and making them more resistant to mechanical stress.
Revolutions usually change — or at least try to change — unsatisfactory situations on land. This revolution will take place on water and will change the safety and operating lives of modern ships from the foundation up — or ships will simply continue to be built as they have been for more than a century.
SPS — Sandwich Plate System — is the ingenious formula for a completely new type of shipbuilding, which ELASTOGRAN has developed together with Intelligent Engineering, a company based in Canada and Great Britain.
Instead of conventional steel construction with complex struts, ribs and an endless number of welding seams, the future will see two steel plates filled with a liquid polyurethane elastomer, that becomes compact — just like a sandwich. Ship decks and external walls can be repaired, and complete ships as well not too far down the line, can be produced with this ground-breaking technology. The result is so corrosion and fatigueresistant that it is actually beyond comparison with the previous type of construction. SPS has its prow out in front in all respects. In comparison to conventional design technology, the polyurethane layer between the steel plates brings a sustainable increase in stability to the components and makes them more resistant to mechanical stress.
The complete elastomer layer absorbs external influences, which prevents tears and holes from becoming larger. There is considerably less deformation in the event of a collision, which improves safety for passengers, freight and also for the environment. In economic terms, too, SPS has much to offer.
SPS Dream team of polyurethanes and steel
|Application:||Civil Engineering, repair and new construction of ships, bridges, bridge plates, bearing elements in stadiums|
|Properties:||absorbs energy, inhibits vibrations, good thermal and acoustic damping, low corrosion and fatigue, simplified ship construction and maintenance|
Because less steel is used, the total weight of the ship is lower. Many of the steel reinforcements are no longer needed, which also eliminates time-intensive labour. Welding can be reduced by as much as 50%. This drastically reduces down time and associated costs for repairs. Ultimately, the lighter the ship, the lower the energy consumption.
To sum it up for both land and sea: significantly lower costs, significantly higher safety
SPS will revolutionise shipbuilding
Interview with Michael Kennedy, Managing Director, Intelligent Engineering Ltd.
Mr. Kennedy, SPS technology was used in shipbuilding for the first time in 1999. The system is now set to revolutionise shipbuilding. What are the advantages of SPS?
MK: SPS makes it easier to build, maintain and repair ships. That saves time and money. The most important factor, however, is safety. The new material combination of steel and polyurethanes can considerably improve ship safety.
A very important point. We only need to think about tanker accidents.
MK: Ten ships disappear at sea every month around the world, and about 500 people go missing every year as a result of ship accidents. The environment also sustains considerable damage from these accidents. Between 1970 and 1997, an average of 192,000 tons of oil were spilled into the oceans annually. If the Sandwich Plate System is used to make ships safer, everyone will benefit. That is our goal.
Where did you get the idea to develop a composite material for shipbuilding?
MK: My brother Stephen was originally looking for a way to improve the design of oil platforms and ice breakers in the Arctic. But think for a minute — how many of these are there in the world? We realised that it would make much more sense to apply the same technology to oil tankers and other vessels. There are about 87,000 large ships on the seas worldwide these days. Both the environment and safety levels would benefit incomparably if SPS were used.
How did you arrive at the idea of using polyurethane as the material for the "filling" in the sandwich?
MK: The systems used thus far, consisting of steel or steel and concrete, are strong and heavy, but they are not flexible or supple, and tend to become brittle after a while. A system made only of steel would not solve the problem, so we had to find a material that works well together in a composite with steel, that absorbs energy well, and is both flexible and strong. ELASTOGRAN then provided us with the right material: a special PU elastomer, whose formula was tested in more than eighty trials.
How did you manage to convince the industry of the project's feasibility?
MK: It took two years to persuade the major institutions such as the classification societies, the shipbuilders and the ship owners. We developed test methods together that show that SPS technology is not only every bit as good as conventional steel systems, but considerably better in many respects. Lloyd's Register, which may well be the world's most conservative classification society, that is, a technical supervisory body for ships, gave its approval to SPS and described it in almost glowing terms. That set an extremely important precedent for other agencies and for the shipping industry.
What will the future bring for the SPS project and its market potential?
MK: There is an enormous market for our new technology. We are currently discussing plans to construct entire ships with prefabricated sandwich elements. There will be a change in material on the order of the one 150 years ago, when shipbuilders switched from wood to iron, and then to steel. But history doesn't stand still. SPS will have a big influence on engineering practice. We are going to revolutionise not only shipbuilding, but also steel construction in general. As far as the technology goes, we are on the threshold of a new epoch.