What can be considered a good open-water design when it comes to vessels trading in areas obstructed with ice?
Good vessel design will reduce the impact on the environment and have a positive effect on the financial life-cycle cost for the ship and its operators. This much is clear, but how do we achieve this? The answer lies in a correct interpretation and adaption to the operational profile for the trade or service intended for the vessel. But how do we ensure that this performance is attained? It is obvious that an icebreaker operating in the Port of Sabetta has different requirements for open-water performance than an ice-breaking LNG (liquefied natural gas) carrier operating to ports in Northern Europe or for polar research vessels or even exploration cruise vessels. They all operate in icy waters, but with different purposes and different operating profiles. What is most important, the consumption and emissions for a single design point or for the intended sea route?
At SSPA, we talk about “overall performance”. Overall performance, or “efficiency at sea”, is an expression that SSPA uses to cover performance at different draughts, speeds, trims and sailing conditions that the vessel will encounter.
We believe that this approach is the way ahead for ship design and optimisation, since ships in commercial trade seldom only sail at one draught and one fixed speed.
Efficiency at sea starts with a correct analysis of the ship’s functions. A functional analysis for ship performance can be carried out using a defined working environment, i.e. transport demand, sailing route, stakeholders, technical and economic issues, etc. The functions that the vessel should be able to carry out should be discussed between owner, designer, performance experts and builder, then quantified from a performance and economical perspective for the best decision support.
The quantification will show how important open-water performance is and what measures need to be taken for a correctly balanced solution. Ice operation also sets special requirements for the propeller and propulsion system. Ice class rules can have an effect on the shape and material of the propeller, making it harder for the propeller designer to achieve high efficiency and durability.
SSPA’s vast knowledge within the area of cavitation, erosion and propeller-induced noise will help the most experience propeller designer or manufacturer to design and build an outstanding propeller, whatever the configuration might be.
- "If you want to know more about how SSPA can help you, do not hesitate to contact us", says Magnus Wikander, Marketing & Sales Manager, Ship Design, SSPA Sweden.