Ship Selection

This page describes the process used to identify our chosen ship type for the study.

The vessel selection was an important aspect of the project, from previously published papers it was evident that the ship has a large impact on the power savings. The ship speed in particular plays an important role, with lower cruising speeds yielding much higher savings because the forward motion of the ship forces the angle of attack closer to 0°. Reports categorise ship speeds as follows: normal (20-25 knots), slow steaming (18-20 knots), extra slow steaming (15-18 knots), and minimal cost (12-15 knots) (Rodrique, 2017). Given studies in (Pearson, 2014) (Cui, 2018) the chosen ship would benefit much more from the addition of Flettner Rotors if it operated at the “minimal cost” speeds of 12-15 knots.

As well as ship speed, there must also be sufficient space on the deck of the ship for mounting a Flettner Rotor, as well as no immediately adjacent structures on the deck to disturb the incoming wind – such as the cranes often found on general cargo vessels, or stacked containers found on container ships. To maintain the applicability of the study it was important to decide on a ship type that was commonly found travelling across the North Atlantic, and choose a ship of a similar size. The following shows the different types of ships that were considered, including comments on their suitability for the study.

From these preliminary considerations for the suitability of retrofitting Flettner Rotors on to one type of ship, the options have been narrowed down to bulk carrier or tanker type ships. Both ships have suitably low average speeds, available deck space, and no immediately adjacent structures on the deck to disrupt the wind. Bulk carriers make up 13% of ships worldwide by number of ships. Considering gross tonnage of ship, bulk carriers take up by far the most of any ship type, with 38%, showing that although they may not be as common a type for smaller ships, they represent a large proportion of bigger vessels, and are more in line with the scale of this study (EQUASIS, 2017). For these reasons bulk carriers were chosen as the ship type for this study.

References

Cui, T., 2018. Development of a Ship Weather Routing System towards Energy Efficient Shipping, Glasgow: University of Strathclyde.

Encylcopaedia Britannica, 2019. Tanker. [Online]
Available at: https://www.britannica.com/technology/tanker
[Accessed 2 April 2019].

EQUASIS, 2017. The World Merchant Fleet in 2017, s.l.: EQUASIS.

Marine Insight, 2019. What are Ro-Ro Ships?. [Online]
Available at: https://www.marineinsight.com/types-of-ships/what-are-ro-ro-ships/
[Accessed 4 April 2019].

Maritime Connector, 2019. Edamgracht - 9081370 - General Cargo. [Online]
Available at: http://maritime-connector.com/ship/edamgracht-9081370/
[Accessed 4 April 2019].

NIFerries, 2018. In Pictures: Irish Ferries. [Online]
Available at: https://www.niferry.co.uk/in-pictures-irish-ferries-w-b-yeats-returns-from-sea-trials/
[Accessed 2 April 2019].

Nikkei, 2016. China's coal cuts push up bulk carrier rates. [Online]
Available at: https://asia.nikkei.com/Business/Markets/Commodities/China-s-coal-cuts-push-up-bulk-carrier-rates
[Accessed 4 April 2019].

Pearson, D., 2014. THE USE OF FLETTNER ROTORS IN EFFICIENT SHIP DESIGN. London, Royal Institute of Naval Architects.

Rodrique, J.-P., 2017. The Geography of Transport Systems. 4 ed. New York: Routledge.

Stuff, 2015. Cruising on cargo ships. [Online]
Available at: https://www.stuff.co.nz/travel/cruising/74504923/null
[Accessed 4 April 2019].

Container Ship

Lack of deck space and high stacks of containers makes it very unlikely Flettner Rotors would be suitable on this type of ship.

Picture: (Stuff, 2015)

Bulk Carrier

Although the deck space is limited, there is potential for mounting Flettner Rotors with adequate spacing between them and little to no disruption to incoming wind. Many bulk carriers are found crossing the North Atlantic from the Americas to Europe.

Picture: (Nikkei, 2016)

General Cargo

Although abundant with deck space, the cranes often found on these vessels would disrupt incoming wind and reduce the power savings at certain angles of attack. It should be noted that new build general cargo ships can be designed with Flettner Rotors – as shown by Enercon’s 2011 E-SHIP 1 – but retrofitting may be more problematic.

Picture: (Maritime Connector, 2019)

Roll on/Roll off

Roll on/roll off ships often have cargo stored on the top deck of the ship, but adapting to suit Flettner Rotors would be possible, shown by NorsePower and BORE ltd. with the Estraden. These types of ships are less commonly found crossing the North Atlantic, however.

Picture: (Marine Insight, 2019)

Tanker

Tankers come in various forms, some have large pressure vessels taking up deck space as shown. Others (similar to the bulk carrier) have deck space available, no immediate structures, often travel at lower speeds, and are found crossing the North Atlantic.

Picture:(Encylcopaedia Britannica, 2019)

Passenger/Ferries

Although proven to be capable of using Flettner Rotors by a collaboration with Viking Line and NorsePower these ships often travel at higher speeds than bulk carriers and tankers at the size which would make a North Atlantic crossing.

Picture:(NIFerries, 2018)