JPS6127236B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for facilitating turning navigation for an ice-breaking cargo ship, and more particularly to a method and apparatus for facilitating turning navigation for an ice-breaking cargo ship, and more particularly to a method and apparatus for facilitating turning navigation for an ice-breaking cargo ship, and more particularly to a method and apparatus for facilitating turning navigation for an ice-breaking cargo ship, and more particularly to a method and apparatus for facilitating turning navigation for an ice-breaking cargo ship, and more particularly, to provide a substantially vertical ice crushing surface on each side of the ship's hull. By forming and selectively bringing the ice layer crushing surface on either the port or starboard side into contact with the ice layer, the imbalance of force that occurs between the ice layer and the port and starboard sides is utilized to facilitate turning navigation of the ship. The present invention relates to a method and apparatus.

The discovery of oil and natural gas reserves in the Arctic has sparked interest in the development of icebreaking cargo vessels that can be used to transport these resources to refineries and consumers in remote consumption areas.
It's rising today.

Cargo ships are required to have efficient navigation.
That is, fuel consumption must be kept relatively low and sufficient high speeds must be maintained. These requirements necessitate the design of ships with low hull-to-ice resistance per unit cargo capacity. In the past, ships designed to meet these requirements had a relatively large hull length-to-width ratio (hereinafter referred to as the L/B ratio), a narrow bow or a long mid-hull midsection, and port and starboard sides. are characterized by being parallel. These ships are capable of navigating well in frozen waters when sailing straight ahead, but due to their hull design, the channels cut into the ice layer are narrow, and their long, parallel hull structure results in poor turning performance. This lack of turning ability in icy waters poses a significant problem, as it is possible for vessels to alter their course to avoid large areas of ice and for turning passages when entering or exiting anchorage facilities (so-called docks). This is because performance is essential from both aspects of safe navigation and economical navigation time and costs.

In contrast to icebreaking cargo ships, other ships other than those described above have been conventionally designed as icebreakers that primarily escort or assist cargo ships. These ships are required to have a high degree of navigability in icy waters and the ability to clear wide channels for following cargo ships. To obtain the required navigability and wide waterways, the L/B ratio should be relatively low, e.g. from 4.0 to
There has been a need for a squat round hull structure in the 5.5 range, such as that disclosed in US Pat. No. 857,766. The waterline shape of this type of hull allows a certain degree of turning within the limits of the waterway cut by the width of the ship. However, their high beam-to-displacement ratio makes such hull shapes unsuitable for cargo ships. In other words, since the ship has a high width-to-displacement ratio, the power required per unit cargo capacity is relatively high. Furthermore, this high ship width-to-displacement ratio also results in an increase in self-propelled hull resistance per unit displacement.

Other prior art attempts to design a cargo ship with turning performance for cruising in frozen waters include a hull shape with a wide front body as disclosed in Canadian Patent No. 947,483. The purpose of the wide forward profile design is to allow the bow to carve a sufficiently wide channel in the ice layer to allow the relatively narrow midsection and stern of the vessel to turn. This concept was also embodied in the refurbished tanker SS MANHATTAN. The idea of widening the bow section is to achieve a certain degree of improvement in turning performance in icy seas, and the effect is similar to that of the round-hulled convoy or auxiliary vessel described above to some extent. In other words, a wide hull is suitable for ice-breaking navigation.
They require a greater thrust per unit displacement than would be required for similar ships with relatively high L/B ratios, narrow bows, and long parallel midsections, and Therefore, even if turning performance is improved, this comes at the expense of fuel efficiency.

Yet another prior art attempt to design an icebreaking cargo ship with improved turning performance features a "gouged out" section in the hull area aft of the widest section and close to the icebreaking waterline. Some people have devised a hull that does this, for example, as disclosed in U.S. Pat. No. 3,727,571. This hull design is similar to that of the SS MANHATTAN mentioned above, with the only difference being that the hull was widened to its maximum width below the ice-breaking waterline, increasing cargo carrying capacity. That's true. This hull design is
Although not as much as in the case of the SS MANHATTAN hull design, improvements in turning performance still come at the expense of cargo capacity and fuel efficiency.

The object of the present invention is to provide a turning navigation method and method that can exhibit advanced turning performance in ice waters even when the hull has a relatively large L/B ratio and a long parallel section in the center of the hull. Our goal is to provide a hull structure that makes this possible.

Another object of the present invention is to provide a turning aid device configured to change the shape of the waterline of the ship's bow when turning in ice water.

Another purpose is to change the shape of the water line at the bow when turning around in ice, creating an imbalance of forces on both port and starboard sides of the ship, and increasing the net pressure acting almost perpendicularly on one side of the ship. It is an object of the present invention to provide a turning aid device configured to generate pressure.

Still another object of the present invention is to create a turning navigation method for ships in frozen waters that creates an imbalance of force between the ice layer and the port and starboard sides of the ship, thereby creating a pressing force on one side of the ship. The goal is to provide the following.

Still another object is to provide ice-breaking surfaces oriented substantially perpendicular to the waterline and facing at least obliquely to the direction of travel on the port and starboard hull portions above the ice waterline during normal straight-ahead navigation. It is an object of the present invention to provide a turning aid device provided with a mechanism for selectively protruding the ice-breaking surface on either the left or right side so as to come into contact with the ice layer.

More particularly, the present invention is directed to a method and apparatus for turning aid or turning aid for use in the hull of a ship adapted for navigation in icy waters.
The hull is covered with ice layers on both sides of the ship while sailing straight ahead.
There are port and starboard portions that have sloped configurations that apply approximately symmetrically distributed bending forces. Turning aid elements are arranged on the hull on each port and starboard side, and are kept in a position where they do not come into contact with the ice layer when the vessel is sailing straight ahead. Each of the turning aid elements has an ice-breaking wall portion (ice-breaking surface) oriented substantially perpendicular to the water line, at least in a portion facing obliquely to the direction of travel. Either one of the starboard or starboard sides of the almost vertically oriented ice-breaking wall portion of the turning aid element is driven selectively into contact with the ice layer, and the other is placed in a position or posture that does not contact the ice layer. A tilting mechanism or actuating mechanism is provided to maintain the vessel's position.
Improved ship turning navigation is achieved by energizing the hull tilting or actuating mechanism to bring the generally vertically oriented ice-breaking wall portions on either port or port side into contact with the ice layer. It is. A crushing force is applied to the ice layer by the ice-breaking wall that is in contact with the ice layer, while a bending force is continuously applied to the ice layer on the other side of the hull, and this imbalance between the crushing force and the bending force causes the ship to This facilitates turning navigation.

Referring now to the drawings, Figures 1A to 3 show a hull 1 of a type generally suitable for navigation in ice waters, having a bulge 2 according to the invention attached to the forward part 3 of the hull. It is being As can be seen in Figure 3, the bulge-like protrusion 2 is located on the port side 4 of the hull.
It is arranged symmetrically on both sides of the starboard side 5 and includes a forward edge 6, a central edge 7 and an aft edge 8. Each of the edges 6, 7 and 8 has a wall surface 9, 10 and 11 extending generally perpendicular to the waterline. The lower edge surface 12 of the bulge 2 slopes upwardly, as seen in FIG. 1A, and serves to prevent pounding when the vessel navigates ice-free waters. Note that part A in FIG. 3 is a slope part for bending the ice sheet.

Frame lines 14-20 indicate the general profile of a generally sloped hull. In FIG. 1A, a line 16a indicates the water line of icy seawater relative to the ship's hull when the ship is navigating straight through an icy area. The bulge-like protrusion 2 is located above the frozen surface, so it does not affect the ice-breaking resistance of the hull at all when the ship is sailing straight ahead, and for this reason, the hull shape below the waterline is ideal for straight sailing through ice. It will be understood that it may have any desired shape.

The precise shape and positioning of the bulge-like protrusion 2 depends on the hull shape, its structural strength, dimensional limitations of the berthing facilities (so-called docks), expected ice thickness, ship's heel and trim characteristics, etc. It can be changed as appropriate according to the specificity.

Generally, it is preferable that the bulge-like protrusion 2 extends outward beyond the maximum width of the hull.
By extending the protrusion 2 beyond the maximum width of the hull, contact with the split end opened by the forward part 22 (Fig. 2) of the bow is increased, and the unbroken ice layer and the hull side on the outside of the turn are increased. The gaps between the parts are increased.
This increased clearance allows the stern to swing outward a little, allowing for slightly sharper turns. If the hull width is required to be restricted due to the special nature of the docking facility, the protrusion 2 can be configured to be movable toward the front of the hull, thereby reducing the influence of the protrusion on the hull width. .
It is preferable to position the bulge so that it is no further aft than the widest part of the hull, otherwise the line of action of the moment that exerts the ice-breaking force when forcing the hull to turn is This is because the length is reduced. Another effect of projecting the bulge beyond the width of the ship is that it increases the ability of the vessel to cut through the channels opened on both sides during ice formation, thereby increasing the ship's "advance-retreat" During repetition, that is, when the ship is repeatedly moved forward and backward over a distance of several ship lengths, the width of the channel is increased with each movement to increase the possibility of obtaining sufficient clearance for sharp turns. .

FIG. 1B shows the attitude of the vessel relative to frozen water as the vessel makes a starboard turn. The port bulge 2 has been lowered and is in contact with the frozen water. FIG. 2 shows a perspective view of the hull and starboard bulge 2. FIG. 3 is a cross-sectional view along the water line of the first embodiment of the present invention, inclined toward starboard during a port turn (steering).

Figures 4 to 7 illustrate another embodiment of the present invention, in which the bow part of the hull has been modified so that when the vessel is sailing straight ahead, the line indicating the water line The hull portion above 16a is configured to have a surface perpendicular to the water line. The position of this generally vertical surface 24 is indicated by frame lines 25-31. The location where the knuckle line or generally sloped surface changes to a substantially vertical surface is indicated at 32. The substantially vertical knuckle line is located above the waterline and at least in a portion diagonally facing the direction of travel, and the vertical surface preferably extends at least slightly beyond the expected turning navigation waterline. The structure is such that it extends upward. If necessary for navigational performance, the hull may be shaped to widen again above the turning navigation waterline, as shown in FIG. Note that part B in FIG. 6 is a slope surface for bending the ice sheet. Moreover, part C is a vertical surface for crushing the ice plate. Furthermore,
W in FIG. 7 is the starboard turn navigation waterline.

FIGS. 8A-10 illustrate yet another embodiment of the present invention in which movable flaps 36 create a substantially vertical ice-breaking surface that facilitates turning navigation. Movable flap 36
are located symmetrically on both port and starboard sides of the ship at the freezing waterline position when the ship is sailing straight ahead. When the vessel is sailing straight ahead, the port and starboard flaps 36 are maintained in their retracted position, ie, in an attitude that follows the general contour of the vessel (FIG. 9). These flaps 36 preferably extend a distance below the breaking water line and greater than the ice thickness expected to be encountered. An actuation mechanism 37 is provided which moves the flap 36 between a retracted position following the hull contour (section B' in FIG. 10) and an extended, generally vertical position (section C' in FIG. 10). The operating method of this flap extension/retraction operating mechanism 37 may be mechanical, hydraulic, pneumatic, or electrical, and the detailed mechanism forms part of the present invention. However, the flap operating mechanism shall have a function that exceeds the ice-breaking force exerted by the flap when the vessel is turning. The movable flap compartment should be sealed to prevent water or ice from entering the hull. The location and shape of the flaps will vary depending on the particularities of the hull shape and construction, its internal structure, and the anticipated icebreaking operating conditions. The movable flaps reduce interference with access to and from the docking facility, advantageously avoiding the need to heel or trim the vessel during turns. These movable flaps 36 are pivotally supported by longitudinally extending hinges 38 so as to be retractable and protrusive (FIG. 9).

11 to 13 illustrate yet another embodiment of the present invention, in which the effects of the bulge-like protrusion 2 and movable flap 36 described above are combined. Figures 11 to 1
Movable flap structure or movable flap 4 shown in Figure 3
0 requires only a single flap on each side of the hull, as opposed to the multiple flap configuration shown in FIGS. 8-10. Figures 11 to 13
As shown, the movable flap 40 has a vertical pivot 41 and a longitudinally extending horizontal pivot 42.
It is pivoted on. A pair of actuating or locating devices 43 and 44 are provided on each side of the hull for pivoting the flap 40 about a vertical pivot 41 and a horizontal pivot 42, respectively. To place the flap in its ice-breaking vertical position or attitude, positioning devices 43 and 44 are actuated to pivot the rear end of the flap outwardly about the forward vertical pivot 41 and to rotate the bottom of the flap upwardly. It is rotated about the horizontal pivot 42 in which it is located. Alternatively, the movable flap 40 could be located in a parallel extending portion of the hull aft of the illustration, with only a single forward vertical pivot.

In order to turn the vessel shown in Figures 1A-3, the vessel is heeled to one side, for example as shown in Figure 1B, by the use of heel tanks or other known methods to reduce the weight of the vessel. Do this by leaning to one side. In this way, in order to turn the ship to starboard, the port side is lowered and the bulge-like protrusion 2 on the same side is brought into contact with the ice layer. The ship's rudder is operated in the same way as normal steering when turning. The bulging protrusion 2 is substantially perpendicular to the wall surfaces 9, 10 and 1.
1 exerts a crushing force on the ice layer, while the starboard generally curved hull section continues to exert a bending force on the ice layer.

As is well known, the bending strength of an ice layer is much smaller than its compressive strength. Therefore, as mentioned above, the ice layer on the side that receives bending force from the curved hull (starboard side) cannot apply a large reaction force to the hull, but it does receive crushing force from the almost vertical walls 9, 10, and 11. The ice layer on the receiving side (port side) exerts a reaction force on the hull due to compression resistance. the result,
An imbalance of forces occurs between the port and starboard sides of the bow, which forces the hull to turn the bow toward the right, promoting a right turn.

Almost vertical wall surfaces 9, 10 of the bulge-like projection 2
and 11 are not necessarily perfectly perpendicular; this means that the deviation from vertical at the time of contact with the ice layer is the critical angle, i.e. the force applied to the ice layer is bounded by the crushing force to the bending stress. This is true as long as the angle is less than or equal to the angle that changes to . This critical angle θ is a function of the coefficient of friction (μ) between the ship's hull and the ice layer. More specifically, the critical angle θ=tan ⁻¹ (μ). Therefore, μ=0.20
When , θ allows a deviation of 11.3° from the vertical.

A second embodiment of the present invention, shown in FIGS. 4 to 7, has substantially the same specifications as described above for the embodiment shown in FIGS. will be held.

Regarding other embodiments of the present invention shown in FIGS. 8 to 10, or still other embodiments shown in FIGS. 11 to 13, the ship is It can encourage turning navigation. That is, a single flap or flaps on the side opposite to the direction of the turn are projected to form a substantially vertical ice crushing surface, thereby compressing the ice layer as the vessel moves forward. It is. As previously mentioned, the force crushing the ice layer on the side of the ship opposite to the direction of the desired turn is greater than the bending force applied on the opposite side of the ship, so a net turning moment is developed and the desired turn is Navigation is facilitated. Figures 9 through 11 and 13 illustrate the flap being protruded to facilitate a starboard turn, while Figure 12 shows the flap being extended to facilitate a port turn. This shows a state in which the flap is protruded to promote the movement.

The invention may be embodied in other construction details without departing from its spirit or essential characteristics. Accordingly, the embodiments disclosed herein are in all respects merely illustrative and not restrictive, and the scope of the present invention is not limited to what is described in the Detailed Description section above. Rather, the invention is defined by the scope of the claims set forth at the beginning of this specification, and all changes that come within the meaning or scope of equivalents to what is described in the claims are intended to be included within the scope of the present invention. It should be understood that

As explained above, the following three inventions are included in the present specification, and the first invention is a method for navigating a ship as described in claim 1, which includes the following three inventions. A turning aid means for the breaking ice surface, which is substantially perpendicular to the water line, is provided above the part formed in the inclined shape, facing at least obliquely to the direction of travel, and is maintained above the ice layer water line when navigating straight ahead. By tilting the ship's body to the left and right when turning, one of the turning aids applies a crushing force to the ice layer, and the other sloped part applies a bending force. This enables smooth turning, and is typified by the embodiments shown in FIGS. 1 to 7 described above.

The turning method of the present invention skillfully utilizes the property that the compressive strength of the ice layer is greater than the bending strength, and creates an imbalance between the crushing force of the turning aid means and the bending force of the inclined portion on both port and starboard sides. Since this is a device that generates a curve and turns, even a ship with a large L/B as described above can be turned smoothly.
For example, according to the results confirmed by model experiments,
In the case of a normal ice sea merchant ship with L/B = 6 to 8 and a long parallel section in the center of the hull, the turning radius of the conventional hull was about 30 times the hull length L.
According to the present invention, the radius can be significantly reduced to a small radius of 10 times L or less.

The second invention is a method for navigating a ship as described in claim 2, which is a method for navigating a ship that is substantially perpendicular to the water line in the first invention and facing at least obliquely to the direction of travel. The provided ice-breaking surface turning aid means is made to be freely retractable from the ship's surface, and is immersed in the ship's hull during straight sailing, but when turning, one of the sides is made to protrude, and as in the first invention, it The turning is performed by generating an imbalance between the crushing force and the bending force, and the above-mentioned figures 8 to 13
This is represented by the embodiment shown in the figure. This invention also skillfully utilizes the property that the compressive strength of the ice layer is greater than the bending strength, and can obtain the same effects as the first invention. In the case of the first invention, the hull is tilted to the left and right when turning, but this second invention
In the invention, the turning performance is improved by causing the turning aid means to protrude and retract from the surface of the ship's hull without tilting the ship's hull from side to side.

The third invention provides a hull structure suitable for navigation in icy waters as set forth in claim 3. With this hull structure, the navigation method of the second invention can be effectively carried out, and the effects of the navigation method can be achieved.

[Brief explanation of the drawing]

FIG. 1A is a front view of a bow section having a bulge-like protrusion according to an embodiment of the present invention installed on an ice-breaking cargo ship, showing the positional relationship of the protrusion when the ship is sailing straight; Figure 1B shows the positional relationship of the bulge-like protrusions when turning to starboard.
Figure 2 is a front view similar to Figure 1A, Figure 2 is a perspective view of the icebreaking cargo ship with the bulge shown in Figure 1A,
Figure 4 shows the bulge-like protrusion shown in Figure 1A and a partially cutaway cross-sectional view of the icebreaking cargo ship at the waterline when the ship is heeled to starboard due to a port turn in ice water. FIG. 5 is a front view of the hull showing a second embodiment of the present invention in which the bow is provided with a vertical surface above the normal ice-breaking water line; FIG. 5 is a perspective view of the embodiment of the present invention shown in FIG. 4; A diagram showing the hull structure of an ice-breaking cargo ship. Figure 6 is a waterline plan view of the embodiment shown in Figure 4 when the ship is heeled to port for a starboard turn. Figure 7 is a diagram showing the structure of the ship to improve sailing performance. FIG. 8A is a front view of a modified example of the second embodiment of the invention, which has been modified for the purpose of turning the ship, and FIG. FIG. 8B is an explanatory view showing details of the single flap in the embodiment shown in FIG. 8A;
The figure shows the condition of the flap when turning to starboard.
Cross-sectional view of the bow portion of the embodiment shown in Figure A, No. 10
The figure is a schematic sectional view on the water line of the embodiment shown in FIG. 8A during a starboard turn, and FIG. 11 shows a single flap protruding from the hull of an ice-breaking cargo ship;
FIG. 12 is a perspective view showing a fourth embodiment of the present invention in which the hull has an asymmetrical shape and generates a vertical ice layer crushing force. FIG. FIG. 13 is a cross-sectional view of the embodiment shown in FIG. 11 along the water line, showing a state in which the port flap is protruded for turning to starboard. . 1...hull, 2...bulge-like protrusion, 4...
Port side, 5... Starboard side, 36, 40... Movable flap, 43, 44... Arranging means or actuating means.

Claims (1)

[Scope of Claims] 1. An inclined shape is formed on both the left and right sides of the bow part of the ship body so as to apply a nearly symmetrical bending force to the ice layer, and above the slope shape is formed approximately perpendicular to the waterline A turning aid means having a breaking ice surface is provided so as to face at least an inclined direction in the direction of travel, and the turning aid means is maintained above the ice layer water line when sailing straight ahead, while tilting the ship body in the left-right direction when sailing in a turning direction. The ice crushing surface of one of the turning aids is brought into contact with the ice layer to apply a crushing force, while the other is kept in a non-contact state and a bending force is applied to the ice layer by the gunwale to reduce the force generated between the port and starboard sides. A turning navigation method for a ship in an icy area, characterized by turning the ship's body toward a turning aid means in a non-contact state due to imbalance. 2 Forming an inclined shape on both port and starboard sides of the bow of the ship that applies a nearly symmetrical bending force to the ice layer,
A turning aid means having an ice-breaking surface substantially perpendicular to the waterline from the hull surface is removably provided, and the turning aid means is immersed in the hull during straight sailing and maintained at a position along the ice layer waterline; During turning navigation, the ice-breaking surface of one of the turning aid means protrudes from the hull surface to apply crushing force to the ice layer, while the other is retracted to apply bending force to the ice layer, creating a bending force between the port and starboard sides. A method for turning a ship in an icy area, characterized in that the ship body is turned toward a turning aid means in an immersed state due to an imbalance of forces. 3. Form the bow of the hull on both the port and starboard sides in a tilted state that applies a nearly symmetrical bending force to the ice layer,
A turning aid means having an ice-breaking surface substantially perpendicular to the water line is provided at a portion corresponding to the ice layer water line during straight sailing on both starboard and starboard sides, and a position where the ice-breaking surface protrudes from the hull surface and the hull. It is characterized by being able to freely move in and out of a position substantially equal to the surface, and further provided with an operating mechanism that operates to selectively project one of the ice-breaking surfaces of the turning aid means and maintain the other in a retracted state. The hull structure is suitable for navigation in icy waters.