Arctic shipping has been increasing at a notable pace. The Protection of the Arctic Marine Environment (PAME) group found a 25% increase in ship in the last 10 years. Likewise, according to figures from the Northern Sea Route (NSR) Administration, around 300 commercial vessels have this year (2021) been granted permission to sail in the area.
This significant rise in traffic is not only an indication of growing interest in the commercial viability of shipping in the Polar Regions, but also signals a consequent increase in ship owners and operators seeking vessels which are ice class worthy. However, with temperatures on the NSR dropping to -30 – 40°C, and sea ice posing excessive risk of damage to vessels which fail to adopt adequate structural strengthening, a number of vessels will either need to be built, or upgraded, in line with the geographically relevant ice class notions.
Ice class worthy
Among several design and construction ice class requirements, vessels must be able to operate in sea ice and constructed with materials suitable for the ships’ polar service temperature. For example, a vessel’s hull must be optimised to break through ice to ensure safe passage for those onboard. Currently, there exists two options for ship owners and operators seeking to strengthen a vessel’s hull to ensure it is ice class worthy; the first being to build a new vessel entirely and the second to upgrade an existing vessel.
In the current economic climate, and when considering time constraints, investing in an upgrade, in most cases, is the most feasible and therefore most popular option. The upgrade must ensure a vessel’s hull is strengthened significantly and is durable for icy waters – such an upgrade can be achieved through either steel or structural composites, more specifically, our SPS (Sandwich Plate System), which was originally conceived as a solution for improving hull strength for very heavy ice loads.
The problem with steel
Whilst replacement with thicker steel is how a vessel’s ice class rating is increased, there are notable downfalls. Firstly, the thicker steel, which must be installed to upgrade a vessel’s hull to adequate standards, entails cropping out the old hull plating, modifying frames and scantlings, depending on Ice Class notation, which can result in long periods out of service and high project costs. Notch tough steel grades are required at temperatures in the range of -55°C to 0°C and this adds additional cost. It is difficult to produce thick (greater than 50 mm) notch tough steels.
A fresh approach?
At SPS Technology, we have a proven alternative for upgrading a vessel’s Ice Class notation, which is cost effective and time efficient. Our SPS has been used in the industry for decades, and offers a permanent, safe, environmentally sound and cost competitive alternative that delivers improved strength when compared to conventional steel upgrades. Likewise, SPS reduces the major risk of structural distortion as the exterior can be installed without the need to crop out the existing hull and make substantial modifications to the internal structure, insulation and service runs. The structural composite also utilises thinner notch tough steel for the outside (colder) faceplate.
SPS has received class approval from DNV and Lloyd’s Register to upgrade to a higher ice class. However, with the elastomer core specifically tailored to operate in extreme temperatures, between -45°C and +100 °C, higher classifications are also possible. In fact, low temperature tests indicate that the lowest temperature that will exceed the bond strength is approximately -94deg.C for a 25mm core SPS plate, and this lowest temperature can be further reduced by the addition of a reinforcing metal mesh in the core if required.
Therefore, with hard pressed owners seeking increasingly efficient, cost effective and permanent solutions, we see SPS playing a major role in upgrading existing vessels to ice class and supporting those looking to utilise Arctic shipping routes, both now and in the future.