DE1781036A1 - Ship bow - Google Patents

Description

Alexbow Canada Ltd., Calgary / Canada

Ship's bow "

Priority: August 15, 1967 Canada
Application number: 997,888

The invention relates to a ship's bow construction which makes it suitable for use in icebreakers. Embodied the invention has some features of the known bulbous bow, but also has various new features through which the bow is particularly useful for use as an icebreaker.

The so-called bulbous bow was designed for installation in the fuselage of Ocean-going ships developed in order to create certain advantages for the shipping traffic on the high seas, which meanwhile quite well-known have become, mainly good behavior at sea combined with relatively low pluid resistance

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Publishers ^, ^^

when driving through the water. A bulbous bow consists of a part of the ship's hull that extends forward below the waterline extends. This protrusion is generally circular in cross-section, but can also be pear-shaped, with the surface this cross-section decreases, the more the bow turns forward to a curved, bulged (roughly hemispherical) Tapered nose part. This bulged nose part creates a wave system when the ship is in motion, and this wave system creates a certain interference pattern with the wave system generated by the rest of the bow, which as a whole results in a reduction of the total fluid resistance of the ship.

So far, however, bulbous arches have been rather ineffective in breaking ice on those equipped with such arches Meet ships. And for this reason, this particular type of bow construction has not yet been particularly preferred for Ships that are likely to have to pass through a fair amount of ice. One of these is definitely there Construction not obvious as a bow shape, which is suitable for installation in a watercraft, which is specially designed as an icebreaker is.

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Contrary to these prior art references, however, it has been found that the bulbous bow construction is such can be carried out that it is particularly suitable for icebreaker use by certain essential Changes to the dimensions of the bow construction.

The main change that needs to be made '· to the bug for icebreaker work to make suitable, consists in a modification of the cross-sectional shape (at least in the front area of the Bulbous bow) in the sense that the horizontal distance in the plane containing the center line of the bulge from a side edge measured on the other side edge of the bulbous bow becomes larger as the perpendicular distance in the corresponding perpendicular centerline plane from the top surface to the bottom surface of the bulbous bow. Less exactly, but more figuratively expressed, one can say that the bulbous bow is somewhat flattened, i.e. made wider than high, at least in the area that protrudes from the stem. In contrast, are Prior art bulges are generally higher than they are wide, or in some cases have the same height and width (i.e. a circular cross-section).

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In the construction according to the invention, the preferred ratio of width to is. Height (as defined above) in the range of 1 1/2: 1, although in certain circumstances this ratio can go down to about 1 l / ^w : 1 or up to 2: 1.

Other important features of the changes to be made to the bow shape that make the bow suitable for use in ice breaking are described in more detail below.

Another feature of the preferred embodiment of the invention is to provide an addition to the main Bulged nose section in the form of a protruding blade that protrudes upwards to a sharp upper edge and see extending along the central upper portion of the major portion of the bulbous bow and making an ice-splitting puncture. In connection with the use of the term "sharp" in In the present description it should be noted that this expression is to be carried out in the light of the part in question Function as well as in consideration of typical ship surfaces can be seen. For example, the so-called sharp top edge the blade is counted from a round rod with a diameter of, for example, 2.5 cm (1 inch) or more, or less, depending on the size of the ship. During a

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such a surface in the normal sense of the word hardly considered sharp could be described, it is one in comparison with the typical, gently curved surfaces that merge into one another The hull is very sharp indeed. Even a typical ship's stern with a radius of curvature of perhaps 15.2 ^ cm (6 inches) or the like is considered sharp when considering his ability to divide the water and him compares to most other torso curvatures.

Further features of the construction according to the invention are the creation of a V-shape for the lower and lower upper surfaces of the bulbous bow, i.e. those causing the overturning upper surfaces and the lower bow surfaces with considerable tailing; as well as the creation of further, upwardly and outwardly sloping deflecting, overturning surfaces that stand out from the. the rollover causing bow surfaces extend rearward and serve to collect and temporarily support ice while they are deflect it outward onto the piled-up ice through which the ship cuts a gully. These and other features are described in detail in the description below.

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AD

The invention is explained in more detail below with reference to drawings of an exemplary embodiment.

Pig.l shows a general front perspective view of the bow, this view representing more of an artistic impression in order to get a general pictorial idea of to convey the shape of the bow and not attempt to accurately reproduce the relative dimensions of the individual parts;

Fig.2 is a typical hull diagram and shows Boundary lines of the bow construction according to Fig.l, i.e. a series of cuts in vertical fore and aft planes from the Ship center line starting to one side;

Fig. 3 shows a group of body sections of the bow construction, i.e. cuts in vertical transverse planes;

Fig. Jj shows two water lines of the bow construction, i. Sections in two horizontal planes;

FIG. 5 shows a modification of the embodiment shown in FIG .

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BAD ORiG / NAL

In accordance with the conventional drawing practice in shipbuilding, the body sections shown by the curved lines in Figure 3 lie in transverse sections denoted by 16, 16 1/2, 17, 17 1/2, 18, 18 1/2, 19, 19 l / ^h , 19 1/2, 19 3 / ^, 2o. Also shown are three additional cuts in front of the actual fuselage, designated A, B and C, the lines along which cut 19 and the cuts before it are shown in Fig. 2 and all of the cut lines in Fig. ^B . These body sections are thus identified in FIG. 3 by corresponding reference numbers. With the same means, the boundary lines shown by the curved lines in FIG mentioned levels is shown in Fig.3. _{Finally, FIp 1} comes from the designation of the water lines. * · Show that they lie in horizontal planes, which are marked with BCL (bulb centreline plane) and WL (normal load waterline plane).

Various features of the construction of the invention emerge from these diagrams.

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First of all, it can be seen from Fig. 3 that the cross-sectional shape of the bulbous bow 29, i.e. the part in front of the body cut 2o is not circular. If you take section C as an example, you can see that the cross-section is on both sides of the center line CL has a relatively flat upper major surface 3o and a relatively flat lower surface 31 which unite along a curved edge 32. The surfaces 3o represent the surfaces causing the overturning On the underside, the surfaces 31 meet on each side of the center line CL in a sharp ridge 33 and are inclined outwards and upwards in such a way that they show a considerable upswing. According to an alternative solution, you can the surfaces 3o and 31 ', in particular the lower surfaces 31, may be designed with a certain curvature in which it it is usually a convex curvature, with the possible exception of some areas of the upper surfaces 3o, where a certain concave curvature can even be used up to section C. On the top, the surface goes 3o on each side of the center line CL into an almost vertical protruding wall 3 * J, the two walls 3 ^ along their The upper edge are connected to one another by a strong rod 35, which creates a sharp upper edge and thus a so-called split blade 36 forms. As

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As can be seen from the drawing, the blade 36 'forms one additional part of the cross-sectional shape of the bulbous bow, its main part to the plane BCL containing the bulge center line at least at the very front at the point of the section C is substantially symmetrical. Preferably the blade is 36 to be provided, but this is up to you as this part is not essential for the basic bow construction.

A second feature of pattern C (and to a large extent also of patterns B and A and even of the pattern 2o, but to a lesser extent the further the cross-section sform moves aft) is that the width dimension W from one edge to the other in the plane BCL is significantly greater than the height dimension H vertically along its length the center line CL between the crest 33 and point 38 at which the upper surfaces 3o intersect, in which case the additional slitter blade 36 is disregarded and only the cross-sectional area of the major part of the bulbous bow is considered.

Fig. 2 shows that the slitting blade 36 from the side seen from a front area ^ o, at which it is in a sharp nose part *> 1 of the bow (at line D) passes until is beveled to a middle area ^ 2 in height

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and has its maximum height between cuts A and 2o. A rearmost area ^ 3 of the blade merges into the stem ill). From FIG. 2 it can be seen that the stem ^{U] J has} a negative angle of inclination, ie it is inclined upwards and backwards at the loading water line WL and up to a considerable height above this water line.

In front of the plane BCL containing the bead center line, a bow section ^ 5 swings gently downwards and backwards to a floor line H6.

As can also be seen from Fig. 3, behind the bulbous bow 29 on both sides of the hull is a so-called "tumble home" surface ^ 7, which represents a rearward extension of the upper surface or bow-overturning surface 3o and extends rearward and outward to merge with the ship's hull surface 8. This surface, which serves as an ice deflecting surface for laterally moving away the ice broken by bulbous bow 29, faces up and out so that it is suitable for the ice Temporary support, which distracts them when the ship moves forward and a gully opens. The surface ^h 7

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has this upward inclination all the way to the hull surface i> 8 (in the vicinity of the body section 16 and further aft), whereby the last-mentioned surface ^ 8 forms the maximum width of the hull for all components of the same except protruding side areas ^b 9 , which provided on both sides of the ship below the waterline and are centered around the plane BCL containing the bead center line (see FIGS. 3 and 10 ⁾ . The last-mentioned figure also shows how the projection ^b 9 approximately in the body section

16 1/2 disappears because it enters the surface of the trunk 1 * 8 passes. The side projections * »9 can vary depending on However, if required, it can also be omitted.

^{In addition to the surfaces b} l causing the overturning of the Elses, the bow has on each side an outwardly widening surface 52, that is to say a surface which points outwards and downwards.

The lines E, F and G denote the upper deck, the forecastle and the bulwark, respectively.

It should also be noted that, seen in a rather horizontal section at the loading water line WL (see. Fig. ^B ) , the

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uniting, causing the ice to roll over Surfaces 3o and * »7 result in a profile that at the front (apart from the splitting blade 36) is relatively pointed and even more sharply pointed than the horizontal profile of the Bead centerline BCL.

In operation, the bulbous bow behaves essentially as it is known under normal sea conditions « Bulge bow designs, i.e. it contributes to a safe

Behavior at sea, a good location in heavy seas, relatively low Fluldwiderstand at "drive A \ XTch the water and an additional increase to the overall buoyancy to achieve the watercraft. In addition, the bow has mainly because of its "flat" shape, ie because of the fact that the ratio W: H is not the same, but is approximately in the range of 1 1/2: 1 and because of the general cross-sectional shape of the bow, which is continuous extensive surfaces causing the overturning of dee Elses and the various profiles, as well as excellent ice breaking properties in view of the presence of the slotted blade. In the case of ice sheets with a thickness of up to about one third of the draft of the loaded ship, the bow 29 moves under the ice, which is caused by the combined action of the slotted blade 36 and the upper bow surfaces 3o

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is broken. This blade itself is the subject of the parallel running U.S. Patent Application 75o 583 to which respect a detailed description of the specific circumstances by which the slitting blade causes the ice to shatter will.

Broken ice is deflected outwards and upwards along the continuously extending surfaces 3o and 7, which cause the overturning, and then outwards and downwards by the outwardly widening surfaces 52. These surfaces extend outward into the area designated by in FIG. 3, which is above the water line WL. The consequence of this is that ^{broken ice deflected upwards and outwards along surfaces Ü} 7 and finally downwards by surfaces 52 is piled up on the ice cover next to the vehicle instead of being submerged in order to reappear in the ship's lane. This effect creates a cleaner channel behind the ship, in which fewer pieces of ice swim around than was previously the case with conventional icebreakers.

If the ship encounters ice ridges or ice sheets that are so thick that they extend down to below the Extending bead centerline BCL then acts that of the faces

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formed bottom of the bow in the same way as one conventional icebreaker, i.e. it pushes itself on the ice and breaks it with downward pressure, and steers then the broken pieces of ice laterally outwards due to the kinge contained in the inclination of the surface 31. But usually the bow penetrates under the ice so that the main breaking and deflecting action is up. on in any case, the bow has sharp ice-cutting surfaces in both directions, namely the crest 33 below and the Blade 36 above. The V shape bears the underside of the bow also helps to reduce violent impacts in ice-free water.

With the help of the side projections * 9 it is possible to the hull with surfaces 51 of strong rollover effect for the ice in greater proximity to the maximum width of the main hull train than would be possible without lateral projections. This feature has the consequence that a wider groove than the maximum Width of the main hull in the ice is opened before this maximum width enters the channel, creating the possibility ramming is reduced and turning is made easier.

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Despite the numerous differences between the construction according to the invention and conventional bulbous bow designs, by means of which the construction according to the invention is made usable for ice breaking, the construction according to FIG of the invention, but essentially still at least some of the advantageous high-sea properties for the bulbous bow cons structures are known.

Pig, 5 shows a modified embodiment in which the nasal part * 1 'at the bow center line BCL is not as sharp or sleek as the nosepiece ^b l in the embodiment according to FIGS. Apart from changes in the other surface shapes, which are caused by the more blunt nasal plate 1 * 1 *, the bow shown in FIG. 5 embodies all the main features of the bow according to FIG Slit blade 36.

Claims

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Claims (1)

Claims 1. Ship bow construction for ice breaking and normal Ocean traffic with a stem and bulbous bow extending forward from the stem below the loading waterline, the stem forming a negative angle of inclination at and above the loading waterline and the bulbous bow being horizontal and describes the forwardly extending plane containing the bead centerline, symmetrical about that of the perpendicular The main plane of the ship containing the center line is arranged and has a cross-section width and height that extend Weeping clay from a part of the nose continuously to surfaces that merge outwards and backwards into the hull of the ship, characterized in that a) the cross section is designed at least in the front areas of a main part of the bulbous bow such that i) the horizontal distance in the plane containing the bead center line from one edge of the bulbous bow to the others is greater than the perpendicular distance in the plane containing the perpendicular center line of the upper surface of the main part of the bulbous bow to the lower surface of the same, "17 009837/0583 οη fArt. 7 5 1 para. 2 M ₁ ,, ς,., _{3 dpc r,.} ^ . _q ., _{v 4 g} * 17 - ii) and that the upper, partially delimiting the cross-section surfaces upwards in the direction of the vertical The plane containing the center line is inclined and so form bow surfaces which cause the ice to overturn, while the lower, also the cross-section delimiting surfaces downwards in the direction of the vertical The plane containing the center line is inclined so that there is a considerable upswing, b) and that the surfaces merging into one another are designed in such a way that, seen in a horizontal section sji the LadewEsserlinie, they form a profile tapering to the front and have further surfaces causing the ice to overturn, which are rearward of the surfaces causing the overturning continue and extend to the loading waterline to pick up ice, temporarily support it and deflect it outwards as a result of the forward movement of the ship. 2. Ship bow construction according to claim 1, characterized in that the lower surfaces of the bulbous bow are inclined backwards and downwards and merge into further backwards and downwards inclined continuations of the same, which maintained the keel a considerable distance back from the bulbous bow, and that these continuations ultimately merge into the ship's bottom in a plane substantially below the plane containing the bead centerline. 009837/0583 3. Ship's bow according to claim 1 or 2, characterized in that g e that the ratio between the horizontal and vertical distance is in the range of approximately 1 1/4: 1 to about 2: 1. 4. Ship's bow according to claim 3 »characterized by g e k e η η, that the ratio is about 1 1/2: 1. 5- ship's bow according to claim 1 or 2, characterized in that the. Main part of the bulbous bow at least in the front regions is substantially symmetrical to the plane containing the vulcanized center line. 6. Ship bow according to claim 5 »characterized in that the vulst bow has an additional part has, which has a protruding blade that extends from the central upper region of the main part to a sharp Top edge protrudes upwards. 7. Ship bow according to claim 6, characterized in that the blade is beveled in height is to merge to the front in the 'nose part and to the rear in the stem. 8. Ship's bow according to claim 6, characterized in that the cross section is shaped such that that it has essentially flat surfaces on the underside which are inclined downwards and inwards to one another, to the. To form the bottom surface as a sharp comb. 009837/0583 -W- 9 «Ship bow according to claim 3 _S, characterized in that the cross-section is shaped such that it has essentially flat upper surfaces which are inclined upwards and inwards in sight of the blade. ■ 10. Ship according to claim 1 or 2, characterized in that the merging faces of possess behind the Wulstbugteil deflecting surfaces which extend rearwardly and outwardly, to proceed in aen hull, these deflecting surfaces have their part surfaces facing to flat and the outside in order to take up the r'is and temporarily support it and divert it towards the outside when the ship moves forward. 11 «Ship's bow according to claim Q, characterized in that the deflecting surfaces extend outwards have widening areas above the waterline that point outwards and downwards to enclose ice outwards' and deflect down onto the ice sheet adjacent to the ship as the ship moves forward. 12. Ship's bow according to claim 9, characterized in that the surfaces merging into one another have sloping surfaces behind the bulbous bow, which gentle continuations of the essentially flat upper ones Have surfaces and extend backwards and outwards, 009837/0583 - 2o - - 2ο - 17810 ^ 6 to merge into the hull, the distracting Surfaces which cause the overturning of the egg ("tumblehome" surfaces), which face upwards and outwards instruct to pick up and temporarily support ice and deflect it outwards when the ship is moving moved forward, as well as outwardly widening surfaces above the surfaces causing the overturning, the face down and out. 13. Ship's bow according to claim 12, characterized in that g β k e η η, that the deflecting surfaces extend backwards up to the maximum width of the ship's hull * 14. Ship bow according to claim 12, characterized in that the deflecting surfaces according to at the back extend into lateral projections, which towards the sides over the maximum width of the rest The ship's hull protrudes below the loading waterline, with the lateral protrusions then following extend rearward and inward to merge with the ship's hull. 009837/0583