DE2749362C3 - Boat hull with a displacement keel below the waterline on each side - Google Patents

Description

The invention relates to a boat hull with a on each side of the ship below the waterline arranged displacement keel keel, which has an approximately has a triangular cross-section with a concave underside and extends over a considerable part the length of the boat.

Such a boat hull is known from US Pat. No. 2,677,139.

It is also known that the cruising properties of a sailing vehicle are crucial to its design the underwater lateral surface is affected. Measurements by Gilgenast showed that the The hull of a keel yacht only contributes around 30% to the necessary lateral buoyancy and around 70% applied by the keel fin.

The same applies to the propulsion resistance

so the other way around, here the trunk accounts for about 75% and on the keel fin about 25%. It is also known that keel fins with a high aspect ratio have a have greater lateral buoyancy with less drag than keel fins with a low aspect ratio.

The stability of sailing vehicles has a decisive influence on the sail carrying capacity and thus not only on the behavior when heeling due to wind pressure, but also on the achievable speed. Today, fast boats predominantly have wide, round-frame ship shapes with a divided underwater lateral plan and narrow deep keel fins or swords. The ballast! amounts to Keel boats approx. 40% to 50% of the empty weight.

Conventional vehicles with fixed keel keels or rafts have the advantage of being upright If the sailing properties are usually less favorable on firm ground, those of the larger surface and the low aspect ratio of the keels as well as the lack of adaptation of the keels to the changing ones Flow conditions on the ship's hull arises. In addition, these vehicles are mostly used for tidal waters designed for which a large draft is undesirable and with poorer sailing characteristics is bought.

It is therefore the object of the invention to improve the sailing properties of shallow sailing boats, which take into account an area with shallow water are designed to improve.

To solve this problem, a boat hull of the type mentioned is proposed, which according to the Invention has the features mentioned in the characterizing part of claim 1.

The advantages achieved by the invention are in particular that the lateral buoyancy of a The hull of the sailing vehicle with the help of the displacement keel keels with increasing heel is decisive is increased and thereby enables an improvement in the cruising properties. The one to achieve

such optimal cruising properties necessary fin keels or swords can be reduced very much in terms of area. In this way it is possible, totz low hull draft to achieve good cruising properties. By reducing the fin keel resp. Sword area enables an increase in speed.

Due to the wave interference of the bow wave system with the wave system of the displacement keel keels there is a reduction in the wave resistance, which also leads to an increase in speed.

The high dimensional stability achieved by the W-shaped cross-section of the boat hull increases this Sail carrying capacity and enables a considerable reduction in the amount of ballast in overturning-proof vehicles. This increases the speed of the vehicle, especially in light winds. The at flat-bottomed vehicles when driving in a wave trough occurring loss of stability, which lead to capsizing

can does not occur.

In addition, the vehicle has the well-known advantage of conventional Kimmkiclem, sword boats and Flat-bottomed vehicles such as standing upright when dry, even on less firm ones Underground. Another advantage over vehicles with a center keel is that they get stuck can not occur when sailing close to the wind in an inclined position, as the hull draft is with it decreasing heel reduced instead of as with the Miltelkie! enlarged

The lack of windwardness when sailing close to wind in many vehicles with increasing Heeling, which occurs especially in wide, flat vehicles with full aft hulls and to one Loss of speed will result with the help of the displacement keel keels due to their larger size Cornering force and directional stability effectively avoided.

The strong rolling on forward wind courses, which is particularly criticized in shallow, long-chipped vehicles with fetched swords or vehicles with a short, deep keel due to the lack of underwater lateral surface, is largely avoided by using the displacement keel keels, as they can be used as bilge keels with a cheap, without increasing the underwater lateral surface Distance from the roll axis take effect.

The enlargement of the The leeward angle becomes more and more effective with increasing heel Displacement keel with an increase in lateral buoyancy up to heel angles of 30 "avoided.

For the interior of a sailing vehicle J5 result from the arrangement of displacement keel keels new possibilities for interior design, as more volume with unchanged external dimensions for deep storage spaces and a more usable shape with a larger footprint arises. In this way, even with smaller boats, bunks with sufficient space between them can be created be arranged one above the other. The displacement keels allow the installation of deep-set swords that do not affect the interior affect. The ballast required for capsizing-proof vehicles can be detached on the inside over a large area be distributed to both displacement keel kills so as not to concentrate the mass force and the To increase the radius of gyration around the longitudinal axis. This reduces the stress on the trunk and an improvement in the rolling behavior brought about by the knitted to the ends the increasing shape of the displacement keels exerts a cornering force on the fuselage the course stability improves without impairing the ability to rotate. Due to the larger floor area of the Fuselage with the inclined front inner surfaces and the sharp tear-off edges in the rear part of the Displacement keels improve the gliding properties of the vehicle

Advantageous further refinements of the invention are characterized in the subclaims.

An embodiment of the invention is shown in the drawing and will be explained in the following with reference to described in more detail in this drawing

In Fi g. 1 the shape of the displacement keel keel is shown in side view, with curve (B) the upper line entering the hull, curve (F) the lower boundary line of the displacement keel keel and the almost vertical one, only in one direction to the ends of the ship inwardly curved surface (J) (hatched) represents the outside of the displacement keel.

In Fig. 2 the main bulkhead cross-section of the boat hull with the two displacement chimneys on the port and starboard side (hatched) is shown. The surface (I) shows the almost vertical outside, the surface (K) the downward and inward curved underside of the displacement keel.

In Fig. 3, an example of the inclination of the outside (I) up to a maximum of 15 ° from the vertical to the outside is given.

In Fig. 4 an embodiment example of the inclination of the outside (I) up to a maximum of 5 ^f inwards is given. This cross-section is particularly suitable for smaller GRP boats that are to be demolded in one piece.

F i g. 5 shows the special shape of the stern frame (port side v. 0-4) of the displacement keel (hatched) with the characteristic sharp V-shape on the underside of the keel.

F i g. 6 shows the special shape of the foredeck frames (port side v. 5-10) of the displacement keel (hatched) with the characteristic rounded underside. It should be noted here that the radius of the Underside increases towards the front.

F i g. 7 represents the in F i g. 5 and 6 indicated section XX , which is performed at an inclination of 15 ° to the horizontal through the displacement keel (port side). From this, the airfoil profile shape of the displacement keel can be seen, which becomes effective with increasing heel. The suction side of the profile points to the wind direction and the pressure side of the profile points to the flow direction of the water when sailing close to the wind.

For this purpose 2 sheets of drawings

Claims (6)

Patent claims: 1. Boat hull with a displacement keel keel arranged on each side below the waterline, which has an approximately triangular cross-section with a concavely curved underside and extends over a considerable part of the boat length, characterized in that the underside of the displacement keel keel at its deepest Place has a contour (L) that comes close to the half-oscillation of a sine curve, the half-wave length of which corresponds to the distance of the lowest point on the underside of the keel from the entry of the keel into the horizontal boat bottom and whose double amplitude value corresponds to the keel depth (H) unxtr to the horizontal boat bottom, where the underside length (M) of the keel is 80% of the largest half of the boat's width (WJ is (see Figs. 2 to 4). 2. Boat hull according to claim 1, characterized in that the length (A) of the displacement keel keel, beginning at the rear end of the construction waterline (DWL) , is 95% of the construction waterline length (see FIG. 1). 3. Boat hull according to claim 1, characterized in that the upper inlet line (B) of the displacement keel keel in the boat hull, seen from the side, approximates the shape of a trochoid wave, the wave height (D) of which is approximately 7% of the boat wave length (C) and whose greatest distance (E) from the construction waterline (DWL) is 5% of the wavelength (C) (see Fig. IJi 4. Boat hull according to claim 1, characterized in that the lower boundary line (F) of the displacement keel keel has the shape of a flat parabola, the lowest point of which is half the length of the construction waterline (DWL) and the greatest distance (G) from the Construction waterline (DWL) corresponds to twice the value of the keel depth (HJ (see Figs. 1 and 2). 5. Boat hull according to claim 1, characterized in that the crescent-shaped outside (I) of the displacement keel, standing almost vertically, inclined within the limits of 15 "outward to 5 ° inward and only in one direction from its widest point the ends of the ship is curved inward. 6. Boat hull according to claim 1, characterized in that a section guided at 15 ° to the horizontal in the waterline plane through the displacement keel takes the form of an asymmetrical hydrofoil profile, the greatest thickness (O) of which is about 40% of its length (P) from the front is measured, the thickness (O) of which is approx. 15% of its length (P) and the chord of which assumes an angle of 2 ° to 3 ° to the vertical plane of the ship's length (see FIG. 7).