Heavy-lift surfing

Towing kite sail against "gauze burning at sea"

For the British Guardian, it is a historic event: the maiden voyage of a heavy-lift freighter from Bremen to Venezuela. The special thing about it is the recourse to a classic means of propulsion in merchant shipping – wind. A rough towing kite sail is to be set in the fourth week of January and will contribute a good portion of the propulsion.

The killer argument for the use of conventional propulsion systems no longer works well. The times of cheap fuel for ship engines, which sail the world’s oceans with extremely sulfurous heavy oil, and thus "and thus operate a kind of mull incineration at sea" are probably over. Even the most stubborn shipping entrepreneurs were allowed to realize this in the "very conservative" industry, which is always considered to be very conservative.

As Matthias Brake already pointed out here last fall (cf. Sailing ships under the climate flag), the "the approximately 40.000 cargo ships, cruise ships, ferries and fishing trawlers are responsible for 5% of global CO2 emissions. With a consumption of 200-250 million tons of oil per year and 600-800 million tons of carbon dioxide emissions, they are roughly on a par with air traffic". Shipping emits more CO2 than all of Africa, about as much nitrogen oxides as the entire U.S. (11%), and more than 7 percent of sulfur dioxide worldwide. In port cities such as Hamburg, shipping is said to be responsible for approx. 80% of air pollution.

Heavy-lift cargo surfing

Heavy-lift freighter as "kite surfer.Photo: Beluga Shipping GmbH

Not surprisingly, the Intergovernmental Panel on Climate Change (IPCC) became aware of the problem and published recommendations in its report of last year (cf. Climate protection is feasible) made recommendations for the shipping industry. The IPCC experts also mentioned in particular the equipment of tankers and freighters with additional sails. This drive is currently being tested by the freighter mentioned at the beginning of this article on its journey from Bremen to Venezuela. Telepolis asked the Bremen shipping company Beluga Shipping, represented by Verena Frank, a few questions:

What savings do they expect from the towing kite sail?? To what extent is the sail supported by the ship’s engines??
Verena Frank: On the MV "Beluga SkySails" the main engine is relieved by the towing kite propulsion system. For the first months of operation, the multipurpose heavy-lift project carrier is equipped with a 160 square meter rough kite (towing kite). We expect a fuel reduction of ten to 15 percent (= 4-5 tons of fuel) when using the system, equivalent to a reduction in bunker costs of up to 2000 US dollars per day. In the course of the first year of operation, the sail is scaled up to a coarse of 320 square meters. Then a savings potential of 20 to 30 percent is realistic. How the sail is set, how it is recovered? What happens if it falls into the water?
Verena Frank: The towing kite is deployed via a telescopic mast (maximum mast height = 14 m) and, once released, is connected to the freighter only via the towing rope. Setting and recovering is done automatically. The operation of the kite, including its flight maneuvers to further increase the tractive force, is controlled by a control panel from the bridge. In case of an emergency, the kite can be cut to avoid danger for crew, cargo and ship, but the towing kite should be brought to the so-called zenith position to ensure the maneuverability of the ship before deciding on a final cut. If the course is also determined by the sail – you may want to sail a slightly different course, because you can then use the sail better?
Verena Frank: For optimal use of the towing kite propulsion system, we will of course use wind charts as a guide. Other weather data and routing information will also be taken into account. However, as is generally the case in commercial operations, the freighter will choose the shortest routes from port of loading to port of unloading in order to operate economically. The kite can best develop its power in aft winds. On the freighter’s maiden voyage in January across the Atlantic with easterly winds to Venezuela, conditions are good for use. On the return trip, a northern route via Boston back across the Atlantic to Europe, the wind conditions will be even better for a frequent use of the kite sail system. At what angle to the wind can you kitesail?
Verena Frank: The kite’s double-hull profile brings aerodynamic properties that allow it to be ridden not only downwind but also up to 50 degrees to the wind. Three to eight wind strengths allow the use, taking into account that at the flying height of up to 300 meters the winds are stronger and more constant than directly above the water surface. Crossing is not foreseen with the system used. What happens when there is a strong wind? How safe is sailing with the kite sail?
Verena Frank: The towing kite system can be optimally used in three to eight wind strengths. If the wind is too strong, the captain of the ship will ultimately decide to recover the sail. During the extensive test runs on a test and training vessel in the Baltic Sea over the past year and a half, it has been shown that the use of the kite does not pose any serious risks to the ship, crew or cargo, so that it can basically be assumed that the system is safe. How rough is the crew?
Verena Frank: On board are professionally qualified seamen with special knowledge in the application of the towing kite sail system. Captain Lutz Heldt is assisted by a regular crew of 13 men and, for the premiere voyage, by an additional Beluga navigator and ship’s mechanic plus two SkySails engineers. The crew has familiarized itself with the operation of the auxiliary propulsion system through extensive, 12-month system training on the training and test vessel MV "Beaufort" on the Baltic Sea and undergone intensive training. The crew of MV "Beluga SkySails" does not consist exclusively of trained sailors, but of navigators and technicians who are highly motivated to use the new technology, because the crew receives a share of 20% of the saved fuel costs as an incentive and payout.

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