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Redan or Step (H.I.S.)
Since the beginning Ranieri International has studied the effects of fluid dynamics that affect navigation, concerning, particularly, all the boats  with hulls designed to offer high performance and the best comfort. Even if  theoretically by the dynamics point of view, the perfect hull is the one with a flat bottom, thanks to the planing effect already studied and verified in aerodynamics especially on seaplanes, the disadvantages of this concept are many: it is in fact too rigid in rough sea conditions, can be problematic  maintain the direction and, at the same time, can generate a lot of splashing.

The "V"  hull  improves seaworthiness, softening the impact on the waves , but provides a less  aerodynamic lift. Therefore, the designer must consider the energy substraction due to this additional resistance. Only a perfect knowledge of these limits may realize a more appropriate and effective hull design. Achieve the goal means finding the best technical solution for encouraging the expulsion of the water under the hull , creating an effective ventilation that can reduce the pressure differences, without subtracting energy.
Thanks to aeronautical technology used on seaplanes (for a faster take-off keeping  them more stable in landing operations), some very effective solutions have been identified: the redan (or steps). The function of the redan, consist in a lateral deflection of the accumulated water under the hull, in order to form an air cushion able to lighten the pressure.

In fact it is a kind of particular carvings placed under the hull, to promote the exit of the air,  favoring the glide the outside of the air by decreasing the friction resistance , improving lateral stability and eliminating the possible rhythmic oscillation of the boat , defined " porpoising. All tests carried out both in university laboratories , both in the open sea , have shown that the concept is very efficacious, especially considering the primary objectives of Rainieri International, oriented to maximum control and stability as an essential element to ensure safety and comfort. The Ranieri International has directly experienced the effectiveness of redan (step) technology and, thanks to the knowledge and experience gained in the studies on the effects of dynamics fluid, has decided to adopt this technology on all its production, regardless of the economic costs and competitors choices.
The primary objective of the Rainieri International philosophy is to design boats with maximum performance output , the best comfort and more effective optimization of consumption . And always , these concepts have addressed every company project to finalize it to the real needs of the customer from the point of view of aesthetics , quality and safety in all situations of use.

Historically, for Ranieri International, the study and design of the technology applied to the hull, represent a value only if useful to the improvement of existing models, without following the fashions of the moment. For this reason has been decided to equip all its boats of redan technology that can greatly enhance the stability, performance, comfort and safety by offering many nautical masterpieces of high quality and high technology.

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