DE2852434A1 - Catamaran converting buoyant bow and stern elements - are shaped to permit containment of static air bubble and to assist water flow - Google Patents

Abstract

The buoyant elements for fitting to bow and stern of a catamaran, create in effect a single-hull structure, and are intended to permit containment of a static air bubble (3). The size of this, and thus the vessel draught is controllable. The elements (1, 2) are flat-shaped, with flat tops and streamlined undersides. The forward element underside angle of incidence is such that water flow is deflected downwards to complement the body in containing the bubble. Additionally the narrowing cross-section effect increases the dynamic characteristics and reduces static pressure. The bubble static pressure is thus balanced underneath the elements so that water effects a substantial part of the containment.

Description

T i t e l: bow and stern section as displacement

Body between two-hull ships to form a constructive closed single-drum ship with adjustable draft by means of a static air bubble.

Field of application: The invention relates to displacement bodies which it allows between the side hulls and the bow and stern sections, as it were to accommodate static air bubble, for variable regulation of draft and ship displacement, especially for wide ships with large storage and loading areas: Ro-Ro Offshore Tugs Salvage Ships Gas Tankers Marine Research Ocean Development Fisheries Working platforms Helicopter platforms.

State of the art: I. Civil: Dropships and other ships (e.g. Ro-Ro ships) with highly variable low ranks, which carry both overseas traffic as well as landings on open beaches are not known (displacer) II. Military: Systems for using both tasks are not known! Known are landing craft: II 1.) Landing craft with a large draft have the disadvantage that To have to drop off unloading units far from the coast.

II 2.) Landing craft with a small draft have the disadvantage of Heavy seas and long inrun routes (displacer II1 + 2) Hoovercraft air cushions are known and 1.) aprons on all sides (with levitation ships: air propulsion) 2.) quasi-amphybic Vehicles (with aprons on all sides and water drive) 3.) Side wall vehicles (with sta: -or flaps in front and no submerged side walls aft + water drive) and aprons or - State of the art: III 1.-III 3. All ships are not displacers! The operating state is the limbo over Water! Criticism of the state of the art: Regarding I and II, properties already under 1 -II 2 are described.

All of these ships and landing craft can be used during the journey Do not change the depth and the displacement in an adjustable manner without balla or trimming and so that they do not affect their drag coefficients in the various operating conditions. .

III 1.-III 3. are not for the transport of heavy loads Long stretches across the open sea, suitable for all weather conditions, and for bulk transport uneconomical.

Task: The invention is based on the task of the Lücb between the large number of existing air cushion systems and displacement ships to close Ben! Solution: According to the invention, this object is achieved in that hydrodynamically streamlined Conveniently shaped and designed bow and stern displacement bodies make the connection from a two-hull system to a structurally closed monohull ship, and this resulting hull structure between the side hulls on the one hand and the bow and stern fuselage sections, on the other hand, receive a static air bubble can.

Further design.

Through this combination between the displacement of the four torso part and the static air bubble enclosed by it can be a changeable and adjustable ratio between trunk displacement and air-bubble displacement brought about which not only changes the draft, but also through the controllability the possible optimal operating conditions for the desired range of applications and can also be adapted to the given sea conditions and swell can The bow sinker can be optimized in such a way that it is not only suitable for the application the most favorable flow profile but also through the setting angle the front flow closure to the air bubble through the flow directed downwards guaranteed itself.

Continuation of further design: This is created while driving ean flow closure of an equilibrium ratio between the Kp power the flow and the Kp of the air bubble bidet.

This flow closure against the flow changes its position below the bow displacement body ie. of the horizontal surface profile in the constriction cross-section forward at lower speed and forward at higher speed to the rear.

Achievable advantages: the structural assembly of two hulls by the bow and stern displacement bodies shown according to the invention: The with The advantages achieved by the invention are in particular that: a.) without ballast and without trimming, the displacement and draft can be changed in an adjustable manner.

b.) Rivers and shallow water areas can and also be navigated the landings in shallow water harbors and on flat beaches like landing craft is made possible, which significantly increases the economic value of the invention.

C.) the draft according to the operational areas and the swell can be adapted to the specified operating conditions.

d.) similar to catamarans, the roll moments and heel (max 16 °) is improved compared to the monohull ship, and the sea behavior improves with lower horsepower.

e.) larger parking spaces are given by larger ship widths.

f.) a considerable reduction in frictional resistance by eliminating them of the ship's bottom is to be recorded, namely with larger parking spaces and widths.

g,) better maneuverability like the tatamarans.

h.) higher curb clearance and side curb heights.

i.) a lighter trunk weight is achieved.

Description: Between two (or more) asymmetrical hulls - as with catamarans - in contrast to these, a bow and stern displacement body arranged as bow and stern section in such a way that both hulls become one constructive tightly closed monohull ship are joined together.

1.) Bow displacement body.

The bow displacement body as a bow section and a fixed connection between the side hulls, is asymmetrical as a rod or surface with a long thick Streamlined profile formed, which is only flowed around on one side, while the the other side forms the deck floor of the A-deck.

2.) Flow closure at the bow displacement body.

The flow closure should also be under the profile, through the flow itself, the static air bubble between the trunk in the direction of travel forward to lock.

The profile (1) results in a cross-sectional narrowing of the flow between the bow formations of the side hulls and a flow acceleration, so that the dynamic pressure increases and the static pressure decreases.

This profile is to be designed in such a way that the dynamic pressure closes the air guaranteed below the profile against the air bubble and the static pressure forms an equilibrium ratio to the static pressure of the air bubble. ' Through this there is a closure of the static air bubble to the front at a depth that not filled by the bow-displacement body but to a substantial extent by the flow is taken over.

These considerations assume that between the multiple hulls the air bubble is closed up by a deck.

Claims (11)

Claim generic term: Displacement body as bow and stern section between multiple hulls to form a monohull ship to accommodate static Air bubble between the fuselage sections, for adjustable change of the air bubble and the draft's. Characteristic part 1. characterized in that in the bow and Stern area as a fixed connection between the multiple hulls streamlined, planar displacement body arranged with an angle of incidence to the plane of the ship that close the multiple cumofs at the front and back and make the recording more static Allowing air bubbles between the hulls that are open at the bottom. 2.) characterized in that the bow-displacement body with its thick flow profile and angle of incidence directs the flow downwards, that in addition to the displacement body under this another closure of the static air bubble occurs. 3.) characterized in that the bow displacement body with its thick flow profile is designed in such a way that the cross-section is narrowed the dynamic pressure increases and the static pressure decreases and thereby a Equilibrium to the static air pressure of the air bubble can be established and thus - the front end below the bow displacement body in essence Areas through the medium of water (as in 2.). 4.) characterized in that in the profile area of the constriction cross-section the closure automatically forwards or backwards when the speed is changed relocated accordingly. 5.) characterized in that this relocation of the conclusion reaches its desired front and rear limit in the flow profile area, by changing the static pressure on the flow body when the speed changes and simultaneous back pressure reductions. 6.) characterized in that this relocation of the conclusion on the flow body without flaps in certain areas can be regulated by changing des-static pressure'5-and the height of the air bubble in relation to the external draft. 7.) characterized by different interpretations of the surfaces -Profiles, for different application spectrums of the ships, both for optimal long distances as well as with a different surface profile for the special task of the Strand-Landuny can be interpreted. 8.) characterized in that it is below the surface profile the conclusion in the equilibrium relationship between the static pressure of the flow (in relation to the dynamic pressure) on the one hand and to the static pressure of the air bubble on the other hand the most favorable streamline profile between the media water and air the flow itself forms and the most favorable drag coefficient in this area is achieved through nature itself. 9.) characterized in that by means of profile changes Slotted flaps at the end of the profile of the bow displacement body variable Flow patterns are achieved around the design and application spectrum according to (7) to expand. 10.) characterized in that the surface = profile of the rear displacement body -Analogous to (1-9) can be applied taking into account the flow Design for the stern layout and the wake behavior of the current. 11.) characterized in that changes by means of profile plastic coating over the surface profile, by blowing air between the profile and plastic cover instead of a split flap also the profile curvature and thus the flow pattern can experience a controllable change in its effect.