Blade Series 0 to 90° Angle

0-90° is one of the last equipment added to the large  SEIPEM ® trim tabs range and is based upon a new design concept. As usually, system is manufactured with high quality materials and is the result of our technological research developed during our 30 years experience in trim tabs design. Main feature of this model is to reduce planning time for fast speed vessels with consequent improvement of pitch and  reduction in fuel consumption. When installed on semi-displacing hulls, the equipment looks like a keel extension, thus increasing the lift and generating a vertical thrust that sustains the stern of the vessel. The incidence of tab 0 to 90°  allows the more convenient setting to suit any vessel features.The independent motion and the possibility to get tabs at 0° degrees comply with the most precise correction of longitudinal pitch improving vessel stability. Moreover in case of stern wave motion, the use of this system put the hull in the correct trim reaching the safest cruising conditions.
The equipment consists of 2 sturdy tabs, to be hinged on the transom and moved by a pair of double acting hydraulic rams, without any external piping. Each pair of actuators is driven by an independent power unit, reversible type, having small size and compact.
As per traditional trim tabs, control is obtained by a 2 lever switch panel. Additional control station for fly-bridge is available on request.
The equipment can also be provided with monitoring system including integrated sensors inside the cylinders or potentiometers (traditional type) mechanically connected to the rams (one for each tab) and analogic receivers or LED panels.
System consists in 2 tabs having a very small depth (a few centimeters) rotating from their starting position  parallel to the hull until 90° compared to the bottom. Braking effect with 90° incidence is less than a traditional tab having same chord and reaching 20° at maximum and the related force upwards is greater.  This is due to the deviation of water flows running under the keel: the water flow is held by the tab thus creating a hydro-dynamic wedge that diverts the flow and generates an effort  upwards (F) in the stern sections of the keel. As well known, the minimum friction (R) for an immersed body during motion is reached when the body is made of water, or totally covered by the same. Then you can easily understand as the system provides for a great effort (P), subtracting a very few propulsion thrust. Moreover, incidence of tabs can be setted at different positions: starting from 20°, according to tab angle, you can change the effort generated on the bottom of the hull. Having so a superior efficiency compared to traditional tabs, this equipment can also be employed as stabilizer reducing roll of high speed vessels.