All about increasing the speed of ships. Wave resistance. Chasing speed at sea. Layered Plating Group

The pursuit of records is not alien to sea routes. Flight from Europe to North America by plane it takes only a few hours, while the fastest ship takes three and a half days to cross the ocean. If we talk about the transport ships of today and the near future, they still move much slower than the fastest passenger ship 25 years ago. It was not until 1973 that a merchant ship reached a record speed of 33 knots. However, this figure today is just as little representative of the average level of speeds achieved in the merchant marine fleet as in previous years. Average ship speeds are much lower than this maximum achieved by individual ships, and there are reasons for this. Increasing speed, although it leads to a reduction in cargo transportation time, is very expensive financially. VFM ships reach speeds of no more than 60 km/h. As speed increases, the costs of building a ship and operating it greatly increase. The feasibility of increasing speed is also determined by the duration of vessel stays in ports. From an economic efficiency point of view, the increase in speed will only be justified if at the same time improvements in ship handling technology in ports are carried out to reduce docking time. Also, Navy ships maintain this trend, and their speeds range from 50 to 60 km/h. And these speeds are enough to effectively carry out combat missions.

"Peter the Great" reaches a speed of 57 km/h.

"Moscow" maximum speed of the cruiser is 60 km/h.

"Varyag" reaches a speed of 60 km/h.

“Persistent” destroyer speed is 62 km/h.

“Admiral of the Fleet of the Soviet Union Kuznetsov” speed - 53 km/h.

The submarine "Yuri Dolgoruky" surface speed is 28 km/h, underwater speed is 53 km/h.

Multi-purpose nuclear submarine of the 4th generation "Severodvinsk", surface speed of the submarine is 30 km/h, underwater speed is 57 km/h.

The patrol ship "Tatarstan" of project 11661 ("Gepard") is the flagship of the Caspian flotilla. Speed ​​- 52 km/h.

Corvette "Savvy". The speed of the corvette reaches 50 km/h.

Thus, the desire to increase the efficiency of dry cargo ships by increasing their speed, which began in the 60s, was not successful. Qualitatively new conditions arose only after the introduction of containers for the transportation of general cargo. Combined with the creation of special kits for container transhipment, this led to a sharp reduction in the downtime of container ships during cargo operations and provided the necessary prerequisites for increasing the speed of transport ships. Fast ships are very expensive in any case. Despite this, the speed of ships has become of great importance in the competitive struggle in the global freight market, especially for liner vessels. High speed is considered a sign of high competitive ability and serves the respective shipping company to gain or maintain prestige; This phenomenon inherent in capitalist relations of production contributes to the waste of social labor. Operating costs, which increase significantly with increasing speed, are superimposed on the cost of transported goods. This is only justified when transporting valuable general cargo, where high freight rates can be recouped by more fast delivery. As for dry and liquid bulk cargo, due to their lower cost, they cannot withstand large markups on transport, otherwise their further processing will be economically unprofitable. Therefore, among high-speed ships you can only find container ships, horizontal loading ships, refrigerated ships and lighter carriers, i.e. mainly ships intended for the transportation of valuable piece goods, but not tankers or ships for the transport of bulk cargo. It should be noted that recently the number of high-speed vessels has also included tankers for transporting liquefied gases. This type of transport presents a special problem that will be discussed later. Increasing ship speeds, however, is not a purely economic issue. The faster the ship, the sharper its contours it should have. Large hull points, which extend from the ends of the ship almost to the midship frame itself, lead to a very inconvenient shape of the ship's holds from the point of view of stowing cargo during loading, or to large losses of cubic capacity compared to slower ships of similar sizes. At the same time, it is containers that place very high demands on the cubic capacity of ship holds.

The power of the power plant required to move the ship increases approximately in proportion to the third power of the ship's speed. To achieve a speed of 18 knots, a modern 14,000-ton dry cargo ship requires an installation with a power of approximately 8,100 kW, and a container ship with only three times the lifting capacity requires 85 thousand kW to achieve a speed of 30 knots. Along with the need to install such powerful engines on board the ship, it is also necessary to provide for the possibility of stowing fuel reserves for them. If we look at this example, it turns out that for a dry cargo ship for one voyage in East Asia“only” 1300 tons of fuel will be required, while the mentioned container ship will be forced to carry almost 11 thousand tons of fuel with it if it does not replenish its reserves along the way, and calls at intermediate ports are associated with inevitable losses of time. In connection with the further increase in the requirements for the speed of transport ships, it can be assumed that the increase in speeds will be restrained not only by the increase in costs for the construction and operation of ships, but also by certain technical and physical aspects of this problem. The upper theoretical limit of the speed of any ship will obviously be reached when all its useful carrying capacity has been consumed by the mass of engines and fuel reserves. But for merchant ships this option is unacceptable. Indeed, why should a ship go on a voyage if it will not carry any payload? However, nothing else will work if, for example, you set the task of designing a ship with a total carrying capacity of 10 thousand tons for sailing on a line of 10 thousand miles at a speed of 40 knots. The carrying capacity of such a vessel is only sufficient to accept the fuel reserves necessary for the operation of a power plant with a capacity of more than 75 thousand kW. With empty holds and 10 thousand tons of fuel in the double bottom and other compartments, this vessel will begin the voyage as a tanker and arrive at its destination with empty fuel tanks. In practice, however, things will not come to this, if only because the size of ships is growing at the same time as speed. This has a favorable effect on the upper limit of the power of the power plant that can be installed on the ship, but, on the other hand, requires a constant supply of cargo in quantities sufficient to load such large ships.

In addition to the above considerations of weight and size, there is another, hydrodynamic limit on the speed of transport ships, associated with a sharp increase in wave resistance. This follows from the fact that, starting from a certain speed, the resistance of water to the movement of the vessel increases so much that any further increase in speed is associated with an excessive increase in resistance. For example, with a further increase in the speed of a large 40-knot dry cargo ship by just 1 knot, a significant increase in the power of the power plant is required - up to 40%. But such an increase in speed would be too expensive. This creates a speed limit for all vessels floating on the surface of the water. The maximum speed, in accordance with physical laws, depends on the length of the vessel and has different meanings for vessels with full formations and with sharp contours. Predictions of the highest achievable speed are made, of course, only for displacement ships, which, in accordance with Archimedes' law, displace as much water as they themselves weigh. These forecasts do not apply to hydrofoils, hovercraft, gliders, or underwater vessels. Although the speeds currently included in the designs of high-speed vessels with sharp contours always turn out to be below extreme values, nevertheless, a trend is quite clearly visible: high-speed displacement vessels must at the same time be large in size. Thus, forecasts of speed increases must also take into account the size of the vessels. Lengthening a vessel from 300 to 400 m, for example, although it increases the maximum speed by 6 knots, but at the same time increases the vessel's carrying capacity from approximately 40 thousand tons to 70 thousand tons. Such a container ship is designed to transport about 3,000 20-foot containers. All these containers must be brought to the port as soon as possible for loading onto the ship and just as quickly removed from the port after unloading. One cannot fail to note the difficulties of storing such large quantity valuable cargo.

In 1973, the first transport ships with a speed of 33 knots entered service. Research is being conducted in Japan related to the construction of a 35-knot container ship. It is quite possible that by the end of the century the speed of container ships in some cases will reach 40 knots. However, to achieve such speeds, even greater scientific and technological achievements are needed. Significant resistance to the increase in ship speeds comes from sharp increases in oil prices and, as a consequence, fuel prices. Since 1973, fuel prices in international shipping have increased several times. Therefore, now (and in the future) when choosing ships, fuel prices can only serve as purely indicative economic assessments. In this regard, it should be pointed out that faster ships are usually not the most economical. It is noteworthy that the fastest ships are owned by government-subsidized shipping companies. Military considerations are decisive here, since as part of the US global strategy, fast transport ships are assigned important military functions. The impact of these circumstances on international shipping when designing container ships and horizontal loading vessels precludes the possibility of choosing the optimal speed from an economic point of view. The competition of capitalist shipping companies leads to overestimation of the speed of such ships. This is counterbalanced by research and development work leading to the achievement of higher speeds by reducing water resistance and increasing the efficiency of ship power plants. The most commonly used means for reducing water resistance is the bow bulb, which gives maximum effect with moderately sharp contours: with very sharp contours, the bow bulb provides about 5% power savings, with more complete contours up to 10-15%.

The increasingly wide range of hull coatings offered by the paint and varnish industry makes it possible to reduce corrosion and fouling of the hull, which also leads to some, albeit small, reduction in frictional resistance. Much greater effect can be expected in the future from blowing air and injecting high polymer solutions (as far as environmental considerations allow) into the boundary layer between the hull and the water. The effect will come when the costs of these measures are compensated by the benefits from them in the form of power and fuel savings. At present it is still difficult to say when this will happen. To reduce drag, the correct choice of the ratio between the length and width of the vessel is of great importance, especially now, when there is a further increase in the speed and size of ships. All this serves one purpose - the maximum possible reduction in the power of ship power plants. For a displacement vessel of a conventional type, moving at the interface between two media - water and air, a speed of more than 40-45 knots is hardly achievable. If greater speed is required, it is necessary to use new methods of ship movement. This does not mean, however, a simple departure from the currently accepted hull form. The ship's hull must leave the interface and move in only one environment. There are two ways to do this: down, under the surface of the water, or up, above it. In both cases, wave resistance should disappear. Indeed, a vessel can move faster above or below the surface of the water, and speed limits are no longer valid. wave ship hydrodynamic

The move from monohulls to multihulls is also expected to lead to higher speeds. In principle, however, any increase in ship speed is associated with a significant increase in power. It is interesting that the nature of the increase in power with increasing speed is very different for ships different types. The superiority of one type of hull over another is always associated with a certain speed range. If we first ignore the problems associated with the choice of main engines, then for the future, from the point of view of achievable speeds, the following new classification of ships can be proposed:

• -- displacement single-hull vessels moving on the surface of the water, in a semi-submerged state and under the surface;
• -- displacement vessels with two or more hulls, moving on the surface of the water and in a semi-submerged state;
• -- vessels with hydrodynamic support forces: planing and hydrofoil;
• -- hovering vessels: hovercraft with aerostatic support force and ekranoplanes with aerodynamic support force.

In all vessels of an unusual type, the hull of which is either raised above the surface of the water or lowered under the water, wave drag, which is the dominant part of the total resistance of water for ordinary displacement ships, disappears. In reality, such maximum speeds. Underwater transport 50--60 knots. Semi-submersible multihulls 50--80 knots. On hydrofoils 60--100 knots. On an air cushion 80--200 knots.

These speeds are significantly higher than those of conventional merchant ships. The speed range between transport aviation and the merchant marine fleet will be filled, at least in part, by hydrofoils and hovercraft. In any case, ideas about the prospects for the development of ships of these two types go very far. Although projects of heavy, weighing many thousands of tons, hydrofoil and hovercraft with speeds of about 150 knots and even more than 200 knots are recognized as technically feasible, their construction remains unrealized, since there is no socially determined need for this yet. It can be assumed that such projects will take decades to implement, during which time great advances in other areas of transport are inevitable. In the future to efficiency maritime transport High demands will be made. Will it be possible, however, using hitherto known technical means to create ships that can satisfy the wishes of the maritime transport clientele? The increasing level of specialization of ships and the increase in their size create the prerequisites for sea transportation of goods with minimum cost funds. Automation of ship production processes, combined with their high reliability, will also help improve the efficiency of ships. However, is this enough? Will the navy of the future be faced with the problem of meeting new, currently unknown needs of society? Apparently this will be the case. The question of whether the maritime fleet in the future will be able to meet the requirements of high speed transportation of valuable cargo also remains unresolved. Aviation is already an alternative to transoceanic transportation by ship. Achieving high speeds is the most important future task for all international shipping. This means not only the transportation of valuable cargo, but also the expanding ferry services and tourism.

But how can sailing time be reduced if the possibilities for increasing the speed of conventional ferries have already been practically exhausted? Will these transport tasks in the future be assigned to helicopters or, say, airships, or will the operation of high-speed hydrofoils and hovercraft prove to be more economical? Completely new, unusual challenges are facing sea ​​shipping due to more intensive use of northern sea routes. Vessels making their way through the Arctic ice with the aim of bringing this part of the Earth into the sphere economic activity, are the forerunners of the ships of the future. Today it is almost impossible to foresee what demands the extraction of marine raw materials, the importance of which will increasingly increase, will impose on shipbuilding and shipping. From our current point of view, future engineering structures intended for the extraction of marine raw materials on the surface of the sea, under its surface or on seabed, as well as floating enrichment plants, floating liquefied natural gas stations and other floating enterprises must look highly unusual. Naturally, in this promising offshore production process, it will be difficult to draw a clear line between ships and other industrial structures. However, these and other issues will inevitably have to be addressed as we are talking about the courts of tomorrow. New challenges lead to new technical and technological solutions. Along with the ever-improving conventional vessels, the following will also make their contribution to solving future transport problems at sea: vehicles new, non-traditional type.

We can safely say that shipping is the oldest of all existing modes of transport, although it is hardly possible to answer the question of when and where the first ship was built. But in in this case That's not what we're interested in. Let's take, for example, the Greek ships on which Homer's heroes made their campaigns, and a modern high-speed liner. Let's compare them. The difference is definitely huge. Machines with a power of tens of thousands of horsepower, a carrying capacity measured in thousands of tons - all this, of course, testifies to the undeniable progress achieved in shipbuilding over the past two to three thousand years. However, on the other hand, it can be argued that fundamental difference there is no difference between the compared ships. Thus, the shape of the ship's hull floating in the water - with a pointed bow, smoothly expanding sides, and then tapering towards the stern - remained virtually unchanged. And the speed of a modern transatlantic turboprop - winner of the Blue Ribbon - is only 5-6 times higher than the speed of the Odysseus ship, which was propelled forward by two to three dozen oarsmen.

If we compare these results with the progress achieved over much more short term on land, and even more so air transport, then they look more than modest. This suggests that the speed of a vessel in the traditional method of moving through water, whether driven by an oar or a propeller, is close to the upper limit. Of course, shipbuilding engineers continue to work on improving the shape of the ship's hull, and this gives results that are important for the national economy. For example, in the recent past, only by changing the shape of the bow - installing the so-called bulbous extension - it was possible to reduce the overall resistance of the vessel by about 5-7%. But there is no need to talk about any fundamental achievements in this and in many similar cases.

Probably, it is possible to improve the shape of the vessel only to a certain limit, which is already close and which cannot be surpassed. The fact is that even a perfectly streamlined hull, when moving, causes the formation of waves and experiences resistance from the friction of water against its hull. These forces, which impede the movement of the vessel, increase in proportion to the square and even cube of the speed and very quickly reach values ​​that cannot be overcome by any amount of power.

Since they cannot be overcome, you need to get rid of them if possible! This problem arose seriously at the end of the last century. It was then that attempts were made to replace movement in water by sliding along its surface - planing. The first glider, built in 1867 by the Frenchman Ader, developed a low speed - a little over 20 km/h, but its appearance marked the beginning of a new era in the history of the struggle for speed on water. It is noteworthy that its beginning coincided with the first successful human flights in the air, and further development The development of high-speed ships was in close connection with progress in aviation.

In the years that have passed since the testing of the first planing boat, a leap has been made that is no longer comparable to what has been achieved in the entire previous history of shipbuilding: the modern water speed record, set in 1967 on a planing boat with a jet engine, is 459 km/ hour! These results became possible only because planing made it possible to significantly reduce one of the main obstacles to increasing speed - wave drag. On modern planing ships, most of the engine power is no longer spent on the formation of waves, but on overcoming the frictional resistance of the water (on racing planing boats it reaches 60-70% of the total resistance to movement, although its absolute value is much less than that of a displacement vessel). To achieve a further increase in speed with a given limited engine power, this obstacle must also be overcome.

However, the ability to glide along the surface of the water is also one of the inherent weaknesses of the glider. At high speed, there is a danger of completely lifting off the water, switching to ricocheting mode (like a flat pebble jumping on water) and even taking off into the air, the inevitable result of which will be an accident - remember the end of Campbell’s “Blue Bird”! On the other hand, the surface of the water is never as smooth as a concrete road, and in rough waters the same thing will happen to a high-speed glider as to a racing car launched over rough terrain. It is clear that this limits the areas of application of high-speed gliders.

Recently, a number of new methods of moving through water at high speeds have been theoretically substantiated and practically implemented. We are talking about the use of hydrofoils, the principle of hovercraft propulsion, etc. Many of our readers were also interested in the problem of using wheels on water. The incentive for this was very tempting publications in some newspapers and popular science magazines. Here is what, for example, was published in No. 12, 1967, of the magazine “Young Technician”:

“Engineer V. Podorvanov was the first to think of using the almost forgotten “Magnus effect” in water jets. In its design, the cylinders are not entirely immersed in the oncoming flow, but only with their lower part. This is precisely the main advantage of the new design. Cylinder wheels with the least energy losses were especially easy to crush and pull counter jets of water under them. Their lifting force was so great that it lifted the entire hull of the ship above the water, much better than hydrofoils. After all, the resistance of the cylinders is much less than that of hydrofoils. In addition, they rotate much faster than the oncoming jets of water running under them. As a result, additional traction force appears, accelerating the movement of the vessel. The faster the ship speeds, the higher it rises above the water. Here the cylinders only barely touch the surface of the water with their lower surface. A new phase of movement - the cylinders only occasionally touch the water. Increase the speed even more and the ship completely switches to flight mode. Only the propeller pushing it remains in the water. Now the cylinders no longer operate in hydrodynamic, but in aerodynamic mode. The speed of a cylindrical ship can be increased above the surface of the water to 300 km/h, and possibly more, which is unattainable for hydrofoils and hovercraft.”

For now, we will not examine in detail the reality of applying this principle of achieving such high speeds, but let us get acquainted, at least briefly, with the project in question and for which V.P. Podorvanov was issued an author’s certificate.

A fast boat, which has a vertical air rudder and a horizontal stabilizer, is held above the water surface due to hydrodynamic forces generated on the surface of cylindrical wheels - two large bow wheels and two smaller ones in the stern. The wheels roll through the water with slipping and ricocheting, and the axis of rotation of the bow pair of wheels is located in front and above the center of gravity of the hull, bearing 70-90% of the weight of the entire boat. The wheels are mounted on shock absorbers. The movement is carried out due to the propeller stop.

We can also recall the Green Monster jet glider, built by the American Art Arfons to set a new water speed record: car wheels protruding downward are built into its sponson floats. According to the inventor, these wheels, as if on concrete, would roll on the surface of the water. What came of this is still unknown; at least the world record still belongs to Lee Taylor, not Art Arfons!

With a request to evaluate such projects and establish how much they correspond to the fundamental principles of the theory of hydrodynamics, the editors turned to scientists, members of the Scientific and Technical Society of the Shipbuilding Industry named after Academician A. N. Krylov. To clarify the topic of the conversation, we deliberately narrowed the range of questions, setting out to find out the fundamental possibility of increasing the speed of small vessels in contact with water, that is, excluding hovercraft, ekranoplanes, etc. from consideration. summary this conversation.

What can be said about the fundamental possibility of moving on water on copes?

Eng. E. A. Konov: Typically, the possibility of using wheels as load-bearing surfaces was associated with the idea of ​​reducing frictional resistance. This continues to attract inventors to this day. If we turn to history, it should be noted that back in the 30s, the project of a high-speed boat on wheels was proposed by the Englishmen Lambardini and Fidderman. They reported the results of their theoretical and experimental research in 1948 at the Second International Congress on Applied Mechanics. English engineers believed that if they installed a number of freely or forcedly rotating cylinders under the bottom of the ship, then by reducing friction resistance the speed of movement on the surface of the water would increase. But in order to support the ship above the surface of the water, the wheels must simultaneously create an appropriate lift. Essentially, the British considered the movement of the wheel in planing mode. However, as later experiments showed, the hydrodynamic quality (i.e., the ratio of lift to drag) of the wheels can be only slightly more than unity, that is, it always turns out to be significantly worse than that of a conventional flat bottom.

As for the materials on this issue published in some popular publications, unfortunately, they all suffer from scientific unreliability and therefore mislead readers.

Cand. tech. Science M. A. Basin: I don’t understand at all why talk about the planing wheel as a new principle of movement. The task of achieving high speeds when moving through water requires the creation of a planing surface with high hydrodynamic quality. A wheel (cylinder), even rotating in the direction of movement, does not have this quality, since it is a gliding surface with a shape that is far from optimal.

Let us summarize what has been said: the movement of a wheel on the water surface cannot be identical to the movement on land, as Arfons expected, and Podorvanov’s assumptions about the high load-bearing capacity of the wheels during planing are erroneous.

Eng. Yu. A Goldobin: Previous statements have shown that to increase the speed of a ship, putting it on wheels is completely useless. I would like to recall an interesting idea expressed by the famous aerodynamicist Professor Golubev. An ordinary wheel, when moving on the ground at any moment, as is known, has a point whose speed relative to the ground is zero - this is its fulcrum. In the same way, particles of water located at some distance from the hull of a moving ship remain at rest, while particles adjacent to the hull are carried along with the ship by viscous forces.

From this analogy we can conclude that the wheel invented by man is only a rough copy of the vortex mechanism created by nature, which is now commonly called the boundary layer.

The problem is to create an optimal mode of interaction between the boundary layer and the body. In science, this problem is called boundary layer control (BLC).

What is meant by boundary layer control to reduce frictional drag?

: One of the most promising ways to reduce the frictional resistance of a ship is to create a thin air layer on the bottom. At the same time, to achieve high results it is necessary to design a vessel with a special hull shape. The resulting effect is achieved by reducing the frictional resistance of that part of the body surface that is covered with an air layer and, roughly speaking, no longer moves in water, but in air. The air consumption, and therefore the power for blowing, in this case is incomparably less than that of a conventional hovercraft.

Eng. Yu. A. Goldobin: Interestingly, the effect of air lubrication has been noticed on sailing dinghies that have ejectors in the bottom to pump out water that has entered the hull. If the ejectors are opened at high speed, then the air sucked through them under the bottom significantly reduces the resistance and speed of the dinghy, while, despite the additional resistance of the ejectors themselves, it increases noticeably, and an intense air wake can be observed behind the stern.

Eng. A. S. Pavlenko: As reported by the magazine "Air Capital", the Americans, when testing a 9-meter high-speed boat, obtained a 40% reduction in frictional resistance thanks to the use of air lubrication. It should be noted, however, that air lubrication is not the only way to reduce frictional resistance. Of great interest, for example, are malleable body coatings.

Are we talking about “dolphin skin”?

Eng. A. S. Pavlenko: Yes, this name is accepted in popular literature. In principle, the effect of a pliable coating is not difficult to explain; one of them, developed by the American scientist Kramer, is shown in the figure. Bending under the influence of pulsating pressures, the pliable coating evens out and smoothes the flow, absorbs the energy of transverse vibrations of the boundary layer and thus laminarizes it. In tests conducted by Kramer, it was possible to reduce frictional resistance by 40%.

Cand. tech. Sciences V. P. Shadrin: Of course, there is an analogy, but it is far from complete. The principle of operation of dolphin skin, like any biological self-regulating system, is much more complex. The nerve endings that permeate the skin of a dolphin allow it, obviously, to more actively interact with environment and provide additional gains in resistance. The mechanism of this interaction is largely unclear.

There is another way to reduce ship friction - introducing special polymer substances into the boundary layer, for example, painting the outer plating with polymer-releasing paint. It is assumed that the relatively long and flexible polymer molecules are a kind of spring that dampens flow fluctuations in the boundary layer. Located along streamlines, such molecules resist lateral mixing of water and can delay the transition from laminar to turbulent. It is known that the International Sailing Union even issued a special resolution prohibiting the use of such coatings on racing yachts, so as not to give an advantage to individual athletes.

What are the physical basis of the action of polymer coatings and their prospects?

Cand. tech. Sciences A. A. Butuzov: The mechanism of action of polymer coatings has so far been poorly studied. The available experimental information does not yet provide grounds for any general conclusions.

Eng. Yu. A. Goldobin: There is an interesting report about an experiment carried out in the USA. A bucket of polymer solution was poured into the water from the bow of the boat. At the same time, the speed of the ship instantly increased, and a push was felt. The reduction in friction was estimated to be about 40%.

Let us now turn to a more accessible means of increasing speeds. What can we say about the future of hydrofoils! Can pi be named the speed limit that is available to ships on wings!

Cand. tech. Science M. A. Basin: It is perhaps not possible to name any specific value.

Eng. M. V. Mikhailov: In aviation, with increasing speeds, they began to go to high altitudes, where the air density is much less than at the surface of the earth, and therefore there are fewer friction losses. The same thing is happening in shipbuilding - hydrofoils no longer satisfy us, designers are now striving for complete separation of the vessel from an overly dense medium - water.

It seems that we are finally moving to the area of ​​​​application of hovercraft and ekranopans?

Eng. A. S. Pavlenko: There is no point in talking about the theoretically maximum possible speeds using one or another method of movement. After all, there are certain limits up to which the use of each of these methods is practically advisable. For example, a glider moving at a speed of 100 km/h has no advantages over a ship on wings in terms of energy costs, while in terms of seaworthiness it will be hopelessly inferior to it.

Eng. S. B. Solovey: Movement should be considered in the same relationship when using air injection under the bottom of the boat. Each method is effective only for certain combinations of speed and carrying capacity of the vessel.

Many readers of our collection are interested in the possibility of creating a multi-mode boat that could sail equally economically with high speed, and with a small one. For water tourism such a vessel would have no equal. Fans of water recreation often have to travel considerable distances to get to their favorite place. What solutions exist, at least theoretically, in this direction?

Eng. Yu. A, Goldobin: The simplest thing is to load the boat onto the car and throw it where you need it.

Cand. tech. Sciences M. M. Bunkov: On a serious note, we can recommend folding hydrofoils. Another interesting option- hydroskis, patents for which are now registered in many countries. In principle, the purpose of skis is the same as that of wings - to push the hull of the vessel out of the water to reduce its drag. The difference is that, firstly, the skis are installed not across, but along the hull, and secondly, they are not under water, but glide along its surface. When parked and when moving at low speed, the skis are pressed to the bottom and do not affect the amount of body resistance. Of course, the hydrodynamic quality of skis is lower than that of hydrofoils, and with equal power of the mechanical installation, a ship on the wings will be able to develop greater speed. This can be seen even when comparing the drag curves of both ships. But in rough seas, a boat with hydroskis turns out to be more seaworthy compared to a glider. When moving at high speed, skis, gliding through rough water, due to their flexibility, seem to follow its surface and thus dampen and soften the blows of waves, which usually turn sailing on a flat-bottomed boat into torture. To increase the damping effect of skis, Japanese shipbuilders proposed installing them on shock-absorbing supports.

It is known that when accelerating a ship, the wings create enormous additional resistance, which looks like an impressive hump on the graph. Skis do not give such a hump and the resistance of the vessel changes with increasing speed in approximately the same way as that of a conventional planing boat. In addition, by changing the angle of the ski, you can adjust the lift required to lift the body off the water. Anyone familiar with water skiing can easily imagine how this is done.

So: skis, wings, polymers, air injection, pliable coatings - these are the main directions, the main ways to achieve the limits of the possible in the struggle for the speed of the vessel. Each of these areas, of course, can be the topic of a special conversation. Therefore, expressing gratitude on behalf of the readers of “Boats and Yachts” to all participants in today’s conversation, we hope that they will not refuse in the future to more fully present their thoughts on the issues raised from both theoretical and practical points of view.

Usage: the invention relates to shipbuilding and can be used to increase the speed of movement of sea and river boats without increasing their power or to reduce the power of power plants of ships under construction at the design speed. The essence of the invention: to reduce the resistance to the movement of the vessel's hull, the mode of motion of the enveloping water flow is changed by creating a negative dynamic pressure gradient in it, influencing the flow using a rigid fairing connected to the vessel's hull by an elastic connection in the form of a spring and performing an oscillatory movement relative to the hull using a source hesitation. 2 ill.

The invention relates to shipbuilding and can be used to increase the speed of movement of sea and hand craft without increasing their power or to reduce the power of power plants of ships under construction at the design speed. There is a known method of increasing the speed of movement of a vessel in an aquatic environment, which consists in creating vibrations of the working body of the bow of the hull of a vessel progressively moving in the aquatic environment by transferring them to this working body through an elastic connection from the source of vibrations. The disadvantage of this method is the complexity of its implementation. The purpose of the described invention is to simplify the implementation of a method for increasing the speed of a vessel in an aquatic environment. This goal is achieved by using a rigid fairing as a nose working body, and a spring-loaded pusher as an elastic connection. In fig. 1 schematically shows a device for implementing the described method; in fig. 2 - node I in Fig. 1. A spring-loaded pusher 2 is attached to the rigid fairing 1 made of sheet metal, which passes through the hole 3 in the vessel hull 4 and with protrusions 5 rests on a spring 6, which is mounted on a hollow guide rod 7, which passes the pusher 2 through itself and is fixed to the hull 4. To prevent water from entering between the body and the fairing, the gap between the edge of the fairing and the body along its entire length is covered with a strip of elastic material 8, ensuring free movement of the fairing 2 when it oscillates relative to the body 4. The other end of the pusher is connected to the source 9 of vibrations. Due to the pressing of the elastic material 8 by water pressure into the gap, the latter is blocked along the entire length by a strip of reinforced elastic material 10, with one edge fixed to the fairing 2, and the second edge freely resting on the body (Fig. 2). The fairing 2, perceiving the force of hydrostatic pressure, approaches the body when the elastic connection in the form of a spring 6 is compressed. The proposed method is implemented as follows. In a state of equilibrium, the fairing 1 is held at a certain distance from the body 4 by a spring 6, when the force of hydrostatic pressure is equal to the force of elastic compression of the spring 6. If the fairing 1 is brought out of balance by an external force from the source 9 of vibrations and approaches the body 4 at a certain distance, a, then in this position, a force acts on the fairing 1 from the side of the spring 6, under the influence of which it begins to move away from the body 4, pushing away a certain volume of water adjacent to its surface. Under the action of an elastic force, the fairing 1 moves with a speed increasing from zero to the maximum value of the equilibrium position. At the moment of crossing the equilibrium position, the volume of water adjacent to the surface of the fairing 1 has a movement speed equal to the speed of the fairing. Crossing the equilibrium position, the fairing 1, having mass, moves by inertia, moving away from the equilibrium position by the same distance as it approaches the body, while its speed of movement decreases from maximum to zero. The force slowing down the movement of the fairing 1 is proportional to the stiffness of the spring 6. The volume of water adjacent to the fairing, after crossing the equilibrium position of the fairing 2, also moves by inertia, but the effectiveness of the force inhibiting the movement of its particles from the surrounding fluid is much less than the effectiveness of the force , slowing down the movement of the fairing 1. Therefore, having equal speed at the moment of crossing the equilibrium position, the fairing and the adjacent volume of water move away from the equilibrium position with at different speeds, when the speed of the fairing is less than the speed of the water adjacent to its surface. Only at the beginning of the movement of the fairing 1, a positive pressure acts between it and the water, since the adjacent volume of water is accelerated by it from a state of rest. Further, practically during the oscillating operation, a negative pressure acts between the fairing and the water, since the speed of movement of the thrown water is greater than the speed of the fairing 1. If a force from the propulsion is applied to a vessel with an oscillating fairing 1, then during movement it will not experience the force of the frontal resistance of the water, but but on the contrary, the force of attraction by a passing current, since the speed of water escaping from the surface of the fairing is greater than the speed of movement of the fairing. The negative dynamic pressure developed along the surface of the fairing prevents the development of processes in the flow that are accompanied by the occurrence of transverse movement of liquid particles in it, which, according to recent studies, is the cause of hydraulic resistance in turbulent flow conditions. Returning to the idea of ​​a “running wave,” we can explain its occurrence along the dolphin’s body. If we proceed from the assumption that when a dolphin moves, its head performs a back-and-forth oscillation, then it is natural that it is transmitted to the elastic skin of the dolphin, along which a transverse wave of disturbance runs from the head to the tail. The traveling wave is only a consequence of the dolphin's actions aimed at creating a negative pressure gradient, but does not cause laminarization of the flow. The proposed invention solves the problem of influencing the enveloping flow of water in order to laminarize it to reduce hydraulic resistance. Reducing fuel consumption when transporting goods by waterways by significantly increasing the speed of ships indicates the economic efficiency of the proposed method. The inventive method is supposed to be used to increase the speed of movement of ships under construction, for the reconstruction of those in operation, as well as when designing other bodies moving in the aquatic environment. (56) Copyright certificate of the USSR N 1403520, class. B 63 B 1/36, 1985.

Claim

METHOD OF INCREASING THE SPEED OF MOVEMENT OF A VESSEL IN THE WATER ENVIRONMENT, which consists in creating vibrations of the working body of the bow part of the hull of a vessel progressively moving in the aquatic environment by transferring them to this working body through an elastic connection from the source of vibrations, characterized in that a rigid fairing is used as the bow working body, and as an elastic connection - a spring-loaded pusher.

/ pirates, merchants, in order to sell goods on time and escape from pirates, pirates, in order to catch up with merchants, mercenaries, in order to complete government tasks on time, and, of course, rangers, in order to successfully complete everything at once.

Ship speed calculation

Speed ​​is one of the most complex characteristics and depends on a number of parameters, the main one of which, of course, is the rated speed of the engine, which is subject to various acceleration and deceleration effects.

Slowdown effects

Overload

The large mass of the ship, equipment and cargo that it carries in the hold can lead to a decrease in speed. In this case, the deceleration coefficient fluctuates from 1 to 0.333 and is calculated by the formula:

Thus, with a ship mass of 2000 coefficient. will take its minimum value and will not decrease with further increase in mass.

Overheat

Broken engine

Acceleration effects

Equipment

Some acrine equipment or hulls may provide speed bonuses (or penalties) as a whole number rather than a factor.

Fast and Furious

Gaalistra of time

A stimulant that makes the brain work several thousand times faster and, in addition to bonuses to skills, increases the speed of the ship by a third, thereby adding a coefficient to the speed formula 1,3 .

Artifacts

• Psi Matter Accelerator- with the help of his own powerful consciousness, he allows the engine to use the physical laws of psi-space. By implementing some of these laws, the engine significantly increases the speed of movement. In the first and second parts, cosmosgi adds +100 units speed, in KRHD the integer bonus was replaced by a coefficient one - 1,2 , i.e. the bonus is 20% .
• Co-planner- Self-extracting set of additional nozzles, which are connected at the expense of one unused gun compartment. Thanks to the freer release of energy into outer space, the speed of the ship increases. Gives a permanent bonus +100 units to speed.

Speed ​​calculation mechanism

• BS = motor speed
• SW = speed reduction due to overload (0.333 to 1)
• SE = speed reduction due to overheating (0.5 to 1)
• SBE = speed reduction when motor broken (0.6 or 1)
• H = product of all acceleration factors
• FS = sum of all bonuses to speed (including from acrin)

Changes to the speed calculation mechanism in KRHD

• The penalty for a broken engine has been increased to 70%
• Slow effects are applied according to the formula:

• Pure effects (flat) are applied before scaling effects are calculated.
• All speed reductions below 200 come with an 80% penalty
• All speed increases above 1000 come with a 30% penalty
• All speed increases above 1500 come with a 50% penalty
• Any increase in speed above 2000 comes with an 80% penalty

Examples

Notes

Small missile ships today are becoming one of the most popular combat units in the Russian Navy. Not to mention the Soviet MRKs that are in service, for the needs of the Russian fleet, Buyany (project 21631) and Karakurt (project 22800) are being built in parallel in large series. Doctor of Technical Sciences Viktor Dubrovsky prepared an article for FlotProm in which he calculates options for increasing the seaworthiness and speed of ships of this class by changing the shape of the hull.

Introduction

At the same time, one of the aspects of the problem is the extreme need for a broad technical outlook of customer representatives, because awareness of promising capabilities today is inseparable from understanding the full range of possibilities that would appear when using various new types of ships.

It must be borne in mind that modern surface ships are “capacity carriers,” speaking in general terms. This means that their dimensions are mainly determined not by the mass of the payload, but by the deck area required to accommodate it and the crew (taking into account all the areas necessary to control the ship and service its systems and devices). Typically today, the payload of surface ships (NS) with a steel hull and superstructures is within 10-15% of the total displacement, rarely exceeding 20%.

In addition, important operational qualities of the NK are the achievable speed and the ability to maintain it in rough sea conditions. If the first is achieved through modern power plants, then the second is almost independent of the available power of the power plant and is determined by the characteristics of the hull, as well as the presence of pitch control systems. Note that the capabilities of such systems in relation to longitudinal pitching are fundamentally very small for ships of a traditional type.

Let us also note that the speed of travel in waves of sufficient intensity is almost always reduced (or the course is changed, which lengthens the route) to ensure those levels of seaworthiness characteristics that are required for the safety of navigation and the possibility of functioning of all subsystems of the ship, primarily the hull and crew. This influence is greater, the smaller the displacement of the NK and the worse the seaworthiness, determined by its architectural and structural type.

Thus, today the NK must have a sufficiently large deck area, the highest possible seaworthiness and high performance.

All these qualities are more easily achieved when using multi-body NK than with traditional single-body ones. So below, multi-hull NK are considered as promising alternative options for NK, primarily of small and medium displacement, most susceptible to the influence of waves. various types.

Many years of research and practice in the use of several dozen built objects with a small waterline area have shown their significant advantages over traditional ones. To summarize, we can say that a multi-hull object with a small waterline area has the same seaworthiness as a single-hull with a displacement of 5-15 times greater (depending on the degree of smallness of the waterline area that can be ensured when the entire complex of requirements for navigational testing is met).

For example, in Fig. 1 and 2 compare field data on the amplitudes of pitching and rolling of traditional ships with a displacement of 1000 and 3000 tons (corvette and frigate) and a 600-ton ship with a small waterline area (SMWA), designed in the 70s as an experimental one (according to model data tests in the nautical basin of the Central Research Institute named after A. N. Krylov. Options without pitch dampers are being considered.

Rice. 1. Pitch amplitudes in head seas: 1 – corvette, 1000 tons, 12 knots; 2 – CMPV, favorable seas, 10 knots; 3 – the same, head seas, 10 knots; 4 - the same, 18 knots; 5 – frigate, 3000 tons, 15 knots.
Rice. 2. Amplitudes of roll with a lag to the wave: 1 – corvette, 1000 tons; 2 – frigate, 3000 tons; 3 – KMPV, 10 knots, 4 – the same, 18 knots.

It is obvious not only the advantage of the CMPV, but also the inverse - in relation to single-hull - dependence of pitching on the travel speed: with the CMPV, an increase in speed leads to a decrease in the pitching amplitudes. So for these ships, the power reserve actually causes an increase in speed in rough seas - unlike single-hull ships, where it cannot be realized due to the need to reduce speed to maintain the required level of seaworthiness.

However, for the pre-design selection of one or several types of NK, which are advisable to study in more detail, the participants in this choice need to understand as accurately as possible the needs of the Navy, as well as how their provision will affect the final performance characteristics of ships of various types. At the same time, it is impossible to limit the interaction of designers with the customer only to the very early design stage. This interaction must be constant at the pre-design stages, and accessible at all subsequent stages, because at all stages of design alternative technical solutions arise that affect the design results.

It is proposed to consider the sequence of pre-design solutions using the example of a small rocket ship, MRK, since it has a small displacement and therefore can be replaced by a new type of ship without any major disruption to the fundamentals of shipbuilding.

Pre-design solutions

Without a significant increase in speed, the transition to one of the new types of ships will, at a minimum, achieve a more or less (depending on the type) noticeable increase in seaworthiness, which is especially useful for a small-tonnage ship.

Higher seaworthiness, together with an increase in deck area, will make it possible to additionally accept aircraft weapons (drones) and use them quite effectively.

The following discusses possible limitations and requirements that may determine the choice of the types under consideration. Note that to ensure comparability, all options must have the same area of ​​internal decks in the platform connecting the hulls as the area of ​​the internal decks and platforms of the original option. In addition, the same set of weapons is assumed, i.e. its mass, which plays the role of payload when choosing dimensions.

Obviously, there is no restriction on the length of alternative options. However, the draft of the original ship is clearly limited, and the influence of this circumstance should be considered. The same draft can be ensured:
- catamaran (double-hulled ship with traditional hull lines);
- CMPV with a special choice of dimensions;
- semi-KMPV (when the bow parts of the hulls have a small waterline area, and the stern parts have normal contours, which makes it possible to conveniently place a power plant (PP) of almost any required power).

The catamaran will be better than the traditional version, in addition to the increased deck area, in terms of initial lateral stability and by the amplitudes of roll (at approximately equal accelerations of this roll, which can be ensured by a rational choice of dimensions).

A small draft can also be ensured when using a CMPV if the height of its nacelles (underwater displacement volumes) is assumed to be equal to the draft at full displacement. With a draft equal to the height of the nacelles, the CMPV will be used in calm waters, and in rough waters it will take on water ballast to increase the draft, and therefore improve seaworthiness. The volume of ballast corresponds to approximately half of the total volume of the racks (i.e., the volume from the gondola to the platform).

Moving the motors to the platform means using more complex and expensive power transmission to the propulsors, such as inclined shafts, or bevel gears, or electrical transmission. All this complicates and increases the cost of CMPV with limited draft.

The same result - an increase in the waterline area and the resulting deterioration in seaworthiness - will occur when using a semi-CPMV.

Thus, a strict limitation of draft in the initial data will limit the number of types, shape of contours or possible ES options.

It should be noted that all ships with a limited draft must have water-jet propulsion - just like the original traditional ship.

Using the advantages of the CMPV will be the cheapest in the absence of draft restrictions.

One of the conditions influencing the choice of type, in this case, is the height of the main missile launcher. If this height is more than 5 m, which does not allow them to be placed within a two-tier platform connecting the buildings, then it is most convenient to use the option with outriggers; in this case, the launchers will be linearly placed in the superstructure above the main hull - with the possibility of their lower parts being located in the hull rack. In this case, the outriggers and the superstructure connecting them to the hull will provide additional protection for the launchers.

This variant may have the same main engine and propulsion as the original single-hull prototype. You can then expect a reduction in the achievable speed in calm water. However, by reducing speed losses due to waves, the average speed in sea conditions can remain almost the same.

More traditionally, a twin-shaft propulsion system can be used for warships; at the same time, the same speed in calm water will be ensured as that of a single-hull prototype - due to an increase in power and an increase in propulsive efficiency with an increase in the area of ​​​​two propulsors compared to one (at the same draft). At the same time, an increase in the total hydrodynamic cross-section of the propulsors will make it possible to use propellers instead of more expensive and complex water jets. In this case, the average speed in rough seas will also be higher than that of the single-hull prototype.

Finally, the achievable speed of the CMPV can be approximately twice as high as compared to the traditional prototype - of course, with a noticeable increase in the power of the propulsion system and the displacement of the ship.

Thus, depending on the customer’s needs, the following alternative RTO options can be considered when limiting draft:
- catamaran
- CMPV with two drafts, for calm water and for waves, with power plants in gondolas or in a surface platform;
- semi-CMPV (with a small waterline area of ​​the bows and traditional stern contours).

If there is no draft limitation:
- KMPV with outriggers for the same speed range as a traditional ship, single-shaft or twin-shaft;
- double-hull CMPV with double full speed compared to a traditional ship.

Below, as an example, the main results of the approximate choice of dimensions and the expected characteristics of the last two versions of the RTO are briefly shown.

Initial data

With a side height of 6.57 m, the height of the hull can accommodate one or two decks; with an error on the safe side, when estimating the area of ​​the internal premises, including the area of ​​the superstructure, we assume the presence of two decks. Then the area of ​​the internal premises, without flooring the second bottom, will be about 1300 sq. m.

Let's take the payload mass equal to 15% of the total displacement, i.e. approximately 150 t.

We consider the indicated speed and power values ​​to be initial values ​​for design studies.

Options without draft restrictions

KMPV with outriggers

The use of a specific technique that takes into account the features of the CMPV makes it possible to determine the dimensions and characteristics of the CMPV with outriggers in the zero approximation.

The overall width of this option is determined by the requirement for initial stability stated above.

Approximate diagram general location RTO with outriggers is shown in Fig. 3.

KMPV with "semi-planing" contours

The significantly increased power of the propulsion unit compared to previous options requires an increased width of the racks, and therefore leads to an increase in the waterline area. However, in the design mode of full speed, the ship will float to the waterline at the upper edge of the nacelles, so here the area of ​​the waterline of the struts will somewhat degrade seaworthiness only at low speeds. This deterioration should be compensated as much as possible by the pitch control system.

The approximate diagram of this version of the CMPV is shown in Fig. 4.

Approximate data on the main dimensions and main characteristics of RTO options, the draft of which is not limited

The foregoing shows that the variety of multi-hull objects studied can significantly improve the tactical and technical qualities of small and medium-tonnage NK. However, in order to select options that best take into account the needs of the Navy, constant close cooperation between the customer and designers is necessary.