The company named SkySails was founded in 2001 in Hamburg, and entered the maritime market with a ground-breaking idea. The intention was to support vessels' drives with gigantic towing kites, thus reducing fuel consumption by an average of 10 – 30% per annum. Of course, these generously sized flying systems have to be started, controlled and retracted again fully automatically. This is made possible by a take-off and landing system consisting of a telescopic mast, a winch and the electrical control system. It also comprises the so-called flying system, with a control gondola, cable and kite. In this complex system, diverse position signals are required to control precisely defined flying manoeuvres as well as the take-off and landing process.
The position data are registered by rotary angle encoders and transmitted to the control system. Depending on the point of use, transfer is carried out by means of the CANopen, SSI and Profibus interfaces. The encoders must always exhibit high operational reliability in harsh environmental conditions. In addition, the rotary encoders in the control gondola should not be too large or heavy. All of these requirements are met by TWK T series rotary encoders. These encoders offer a dual-chamber design made of seawater-resistant aluminium and are equipped with a stainless steel shaft. Shaft loads of up to 250 Nm are permissible. Dual-chamber design refers to the mechanical separation of the electronics and moving mechanical components, i.e. the shaft assembly and the multiturn transmission. Position registration is carried out magnetically using Hall technology by the internal sensor system, not optically using a code disk. This enables the chamber containing the electronics to be cast, thus achieving systems of protection up to IP69K. In the case of absolute rotary encoders, a distinction is always made between a single-turn and a multiturn design. In the take-off and landing system, the cable extension length is registered on the winch using a TRD type Profibus multiturn encoder. The rotational angle of the telescopic mast and the extension angle of the cable are registered with a TBD type Profibus single-turn encoder.
SkySails Power GmbH offers an energy generation system that is based on the towing kite system. The so-called upper winds at a height of 200 m to 800 m are used for this. Energy is produced by means of a generator connected to the cable winch. Electricity is generated when the kite ascends. As of a specific extended length, the kite steers to a position in which only low tensile forces prevail. The cable can now be wound in with little energy consumption. This cycle can then be repeated as many times as desired. The planned systems are intended to have an installed output of up to 7 MW.
