The hulls of all heavy cruisers of the Admiral Hipper type had bulbous formations in the bow underwater. The picture of the cruiser "Prince Eugene" was taken on August 22, 1938, on the day the ship was launched. The bulb is clearly visible in the bow of the hull. It reduced wave formation, reduced the resistance of the hull during the movement of the ship and increased the stability of the ship on the course. Despite the presence of a bulb and an "Atlantic" stem, the deck in the bow of the cruiser was heavily flooded with water when moving, even in relatively calm weather.

ADMIRAL HIPPER, 1939

PRINZ EUGEN, 1942

The heavy cruiser "Blucher" on trials in the Baltic Sea after repair, the picture was supposedly taken in March 1940. The stem is of the "Atlantic" type, the chimney is equipped with a visor, like on the pipe of the cruiser "Admiral Hipper". "Blucher" is equipped with a FuMO-22 radar, the antenna of which is mounted on the front tower-like mast above the optical rangefinder.

Admiral Hipper-class cruisers

Heavy cruisers became a new type of ships that appeared as a result of the conclusion of the Washington 1922 and London 1930 naval agreements. These were ships with a displacement of 10,000 "long" tons (10,161 metric tons) and armed with 203 mm main battery artillery. All the leading maritime powers of the world - Great Britain, the USA, Japan, France and Italy - started building heavy cruisers. Germany, however, remained constrained in its desires by the restrictions of the Treaty of Versailles. The Anglo-German naval agreement of 1935 allowed Germany to have a navy with a total tonnage of 35% of that of the British navy. The agreement specified the tonnage, but not the class of ships, as a result of which Germany received a legitimate opportunity to build ships of any class, including battleships and heavy cruisers. Under the agreement, the Germans could build five "Washington" cruisers with a total displacement of 51,000 "long" tons. German representatives informed London about the start of construction of two such cruisers immediately after the conclusion of the agreement. The first ship, the cruiser H (ERSATZ HAMBURG), was laid down at the Blom und Voss shipyard in Hamburg 11 days before the formal signing of the Anglo-German Naval Agreement.

The specification provided for the construction of a cruiser with a displacement of 10,000 "long" tons with maximum speed at 33 knots, armed with eight to nine 152-mm guns, with adequate armor, the estimated cruising range was 12,000 nautical miles (22,238 km). According to its characteristics, the German ship was very close to the French Algiers-class cruisers and the Italian Zara-class cruisers, the latest for that period and the most successful ships of this class in the world. The Germans failed to build complete analogues of French and Italian heavy cruisers due to restrictions imposed on the displacement of the ship. The designers again had to go through compromises. The cruiser "H" (during the descent received the name "Admiral Hipper") and the cruiser "G" ("ERSATZ BERLIN" - "Blucher") turned out to be slower against the terms of reference, not so well protected by armor, the cruising range turned out to be much less than planned. All the shortcomings were the result of the need to fit into a predetermined upper limit of displacement. "Admiral Hipper" entered the combat structure of the Kriegsmarine on April 29, 1939, "Blucher" - on September 20, 1939.

Solemn launching in Bremen on January 19, 1939 of the heavy cruiser Seydlitz, the second ship of the second group of heavy cruisers of the Admiral Hipper class. The Seidlitz was launched after the Prinz Eugene and before the Lutzow. These three ships initially received lengthened "Atlantic" bows. The anchor will be released as soon as the ship is on the water to slow down the reverse movement of the hull after the descent. During the descent, larger anchors were used compared to the regular ones. The coat of arms of the Seydlitz family is reinforced in front of the anchor clewse, however, before the “baptism” of the ship, the coat of arms is draped with fabric. Above the waterline, the cruiser's hull is painted in Schiffbodenfarbe 312 Dunkelgrau, below the waterline in Schiffbodenfarbe 122a Rot. The waterline stripe is Wasserlinienfarbe 123a Grau.

The unfinished heavy cruiser "Lutzow" is being tugboats to the Soviet port, April 15, 1940. Only the tower "A" of the main caliber is fully equipped and mounted, the 203-mm guns of this tower fired at the Nazi invaders during the defense of Leningrad.

"Admiral Hipper", just out of repair, in the ice of the Kiel Bay. The stem on the ship has been replaced, it has become inclined, but still straight, not rounded. A visor is mounted on the chimney. A FuMO-22 radar antenna is installed above the optical rangefinder on a tower-like mast. In early February 1940, when the ice weakened, the cruiser moved to Wilhelmshaven.

The command of the Kriegsmarine ordered three more ships authorized under the Anglo-German agreement: the cruisers "J", "K" and "L" ("Prince Eugene", "Seidlitz" and "Luttsov", respectively) in 1935 and in 1936. By this time, ship designers could no longer pay attention to any contractual restrictions, so the ships turned out to be larger in size, and the displacement was increased by 1000 tons. The armor, armament and speed of the cruisers remained at the same level, but the cruising range increased by 14%.

"Admiral Hipper" takes on board the landing force, Cuxhaven, Germany. The troops are to be delivered to Trondheim as part of Operation Weserübung. The picture was taken on April 6, 1940. With their unusual appearance, mountain rangers arouse genuine interest among the sailors from the cruiser's crew, who crowded around the railing of the ship's deck. The upper parts of the main battery turrets are painted yellow. A 20-mm anti-aircraft gun is installed on the roof of the tower "B" of the main caliber.

The sides of the vessel at the extremities are brought together, connecting at the stem and sternposts. In the stern, above the load waterline, the continuation of the sides is also a stern gap. Majority stem sea ​​vessels It is basically a forged or rolled steel bar of rectangular section (see Fig. 56).

Rice. 56. Stem.

Above the load waterline, the area of ​​this section can gradually decrease, reaching at the upper end up to a value of 70% of normal. If the stem, due to its great length, cannot be made at the same time, then it is made up of separate parts connected on the same lock that was shown for the bar keel. The same lock connects the stem to the bar keel, if the vessel has the latter. If the ship has a horizontal keel, then the connection is usually somewhat more complicated. In this case, as can be seen in the same Fig. 56, at the stem, the lower part (sole) is made shaped, in the form of a special steel casting, attached to the lock to the rest of the stem. The shape of the stem sole, as can be seen in the figure, is such that gradually turning towards the bottom into a trough-shaped section, it allows a gradual transition to a flat, horizontal keel. The first, nasal sheet of the horizontal keel, obtaining an appropriate trough-shaped form, covers the bottom end of the stem and, riveting with it, thus gives the required connection of the stem with the keel. The sole of the stem - usually extends to the collision bulkhead and in the forepeak is connected to the vertical keel brackets mentioned earlier. For this purpose, in the casting of the sole, the stem is made vertical longitudinal rib. At contemporary very large ships the stem sometimes gets a much more complex shape. Firstly, due to its large size, it has to be made of cast steel, as can be seen in Fig. 57;

Rice. 57. Cast stem.

at the same time, like a casting, it already receives a trough-shaped shape along its entire length. On the stem locks, the same trough-shaped, forged short fittings are placed to cover them (Fig. 58). A trough-shaped casting for greater strength is made with a number of horizontal ribs inside. The lock connection of the individual cast parts that make up the stem is bolted, of the flange type (see Fig. 58).

Rice. 58. Cast stem lock.

In its lower part, as can be seen in Fig. 59, modern stems are beginning to be given a pear-shaped, or rather “bulb” shape, in order to achieve better streamlining of the bow of the vessel with water cut through by the lower part of the stem during the course. propeller shafts of the vessel with propellers located at the ends of the latter, as well as the ship's rudder is also hung here.The design of the sternshaft therefore receives a close connection with these devices and, depending on the nature, takes on a different form.Therefore, we first consider the location in the stern of the vessel of these devices. With regard to the output of the propeller shafts and the location of the propellers, here it is necessary to distinguish between two main cases: a vessel with an even number of propeller shafts (and with it propellers) and with an odd one. In a single-screw vessel, the propeller shaft is located in the diametral the plane of the ship and therefore its axis lies in the plane of the stern; the sternpost shall be so designed as to give room for the end of the propeller shaft to emerge from the hull of the vessel and for the position of the propeller at that end.

In a twin-screw vessel, the propeller shafts pass on both sides at a certain distance from the center plane of the vessel, sufficient so that, when the propeller shaft leaves the vessel's hull, the propeller mounted on the end of this shaft can rotate freely without touching the vessel's hull. For the latter purpose, in addition to a sufficient distance of the axis of the shaft from the diametrical plane, a sufficient removal of the end of the shaft back to the stern from the place where it exits from the ship's hull is also necessary. In the case of a twin-propeller vessel, it is easy to imagine that there can be complete independence between the sternpost (located in the centreline) and the propeller shaft exit device and propeller location (located away from the centreline). However, as we will see, this is not always the case, and often, nevertheless, a connection between them is established.

Rice. 59. The bow of the ship with a cast stem.

Rice. 60. Ordinary sternpost and steering wheel.

On the design of the place where the propeller shaft exits from the ship's hull, we will focus further on.

As for the rudder device, the latter of a sea vessel is always in the diametrical plane and is suspended directly on the sternpost. It affects the shape of the sternpost depending on its design, namely, depending on whether we are dealing with a steering wheel of a conventional design, the plane of which is on one side of its axis of rotation, or with a steering wheel balancing type, in which a known part of the plane is also in front of its axis of rotation (the advantage of this type of steering wheel is that it is easier to turn it around the axis). The rudder of the balancing type in its design can be of two types that affect the shape of the sternpost, namely: it can have only the lower part of its plane protruding forward from the axis of rotation, or it can have a part of its plane protruding forward along its entire height. The rudder of the latter type, of course, cannot be hinged to the sternpost, which, on the contrary, is mainly the case with all other types of rudders.

Rice. 61. Steering wheel balancing type.

All these combinations of rudder devices and the location of propellers and propeller shaft outlets can be seen more clearly in Fig. 60-66. All possible other combinations of these devices can be imagined easily on the basis of the same figures.

1) In fig. 60 shown aft a single-rotor vessel with a simple rudder hinged to the sternpost; a clearance is provided in the sternframe for locating the end of the propeller shaft with the propeller in it.

2) In fig. 61 shows the lower part of the stern of the same single-rotor ship, the rudder of which, however, rotates around the axis (shown by the dotted line), so that part of the rudder in its entire height is ahead of the axis of rotation (balancing type rudder).

3) In fig. 62 shows the lower part of the stern of a three-screw vessel, in which one screw is in the diametrical plane, while the other two (one left screw is visible in the figure) are located on the sides; the rudder of this vessel, such as balapsing rudders, is suspended on hinges, having only a part of its lower area protruding forward; the sternpost must have a complex curly shape.

4) In fig. 62 a twin-screw vessel with the same rudder is filmed on the slipway; the structure of the exit of the left propeller shaft from the ship's hull is clearly visible in the foreground of the picture.

Fig. 62 Stern of a three-bay vessel with a semi-balanced rudder.

5) In fig. 64 shows the rudder of a simple type of twin-screw ship, suspended on hinges. To support propeller shafts emerging from corps boats with a large offset at the propeller, there is a special external bracket.

Rice. 63. Stern of a twin-screw vessel with a semi-balance rudder.

6) Figure 65 shows the outlets of the propeller shafts with propellers near a large four-screw vessel (two right guys are visible in the figure; two of the same propellers are located on the other side of the vessel).

Rice. 64. Stern of a twin-screw vessel with an external bracket.

7) Finally, in fig. 66 shows the steering frame (not yet sheathed with sheets) of a baluster-type steering wheel without hinges. A rudder of this type is often used in a twin-screw or four-screw vessel shown in the previous figure; the sternpost in this case gets a completely peculiar shape.

Rice. 65. The output of the propellers of a four-screw vessel.

Rice. 66. Sternpost with balance wheel.

Turning to the consideration of the design of the sternposts themselves, we must first of all note that only in very small marine vessels the sternposts are made forged, but usually, due to their complex shape, they have to be made of cast steel, made up of separate parts. These parts are connected on the locks of the same type that were considered at the stems. However, due to the fact that the sternframe has to perceive the work of the propeller shaft, these locks are made somewhat more solid.

Rice. 67. The sternpost of a single-rotor ship.

The sternpost of a small twin-screw vessel has the simplest form. This form differs from the stem only in that its horizontal and vertical branches converge at a right angle and the vertical branch is provided along its height, from the bottom to the aft gap, with loops for hanging on the rudder stern, and below - with a heel to support the latter. The rudder heel, in order to avoid damage to the rudder when the bottom of the vessel touches the ground, is always recommended to be made slightly raised against the keel line. The hinges and the heel must be made integral with the stem. The sternposts are connected to the keel in the same way as it was indicated for the stems, and for better connection with the ship's hull, the sternpost sole should have a length of at least 8 times the width of its body (usually 4-5 spacings). The upper branch of the sternpost, rising upward, enters the aft gap and here, inside the vessel, is firmly riveted to the transom bulkhead.

In large twin-screw ships, and especially with semi-balanner rudders, the sternpost, if it is independent of the output of the propeller shafts, receives a somewhat more complex form of a steel casting, similar to the casting shown in Fig. 66. The designs of these sternposts are independent of the exit of the propeller shafts from the ship. If the sternpost of a twin-screw vessel is connected with the outlet of the propeller shafts, then its shape turns out to be extremely complex. Therefore, we will first consider the stern of a single-rotor vessel. This stern is inevitably associated with the output of the propeller shaft. Therefore, its shape takes the form shown in Fig. 67, and in the lying form (manufactured) - in fig. 68. Here the sternpost already forms, as it were, a frame, inside of which the propeller is located.

Rice. 68. Photo of the sternframe of a single-rotor ship.

Rice. 69. Stern tube with mortar, (twin-screw vessel).

Through the front of this frame, called starnpostom, the end of the propeller shaft enters this frame, for which the corresponding hub is arranged in the starnpost (visible in the foreground at the lying sternpost). This hub (often called an apple) from the inside of the vessel enters the end of the stern tube through which the propeller shaft is removed from the vessel's hull. This pipe passes through the afterpeak, being fixed with its opposite end on the afterpeak bulkhead. Thus, the propeller shaft from the engine goes through the tunnel of the propeller Ball, then through the stern tube and finally goes out (see Fig. 69). The second part of the sternframe (Fig. 67), on which the rudder is hung, is called the ruderpost and it is similar to the same part of the sternpost of a twin-screw vessel. For greater connection of the sternpost with the ship's hull, in addition to the previously indicated connection of the upper part of the rudder post with the transom bulkhead, the starpost also has in its upper part a branch that usually also enters the vessel, which is connected inside the vessel with a specially reinforced floor located in the afterpeak - above the frame of the sternpost ( see Fig. 67, 70, 71).

Rice. 70. Asterpost with trihedral cross-section starnpost.

The sections of the stern frame parts are usually made rectangular; the heel between the starpost and the ruderpost is made flatter and wider. The upper parts of the stern legs usually have flanges for better attachment inside the vessel to the transom bulkhead and floor.

Recently, the sternposts of single-screw ships have been made, as shown in fig. 70, with a trihedral section of the starnpost, pursuing the goal of better streamlining it with water jets during propeller operation.

A somewhat special shape, shown in Fig. 71, has the stern of a single-rotor vessel, equipped with the previously mentioned balancing rudder, rotating around the axis. This axis in this case, as seen in Fig. 71, replaces the usual rudder post. The steering wheel bearings cover this axis, and the steering wheel can thereby rotate around it. We do not dwell on the special design of the rudder itself, which at the same time has a fish-shaped cross section (for the purpose of its better streamlining), since consideration of the rudders, which already belong to the equipment of the ship (to ship devices), is not part of our task.

The section of the branches of the stern post above the aft gap can gradually decrease, reaching at the upper end up to 50% of their normal section below, at the gap.

Rice. 71. Asterpost without a rudder post.

Now let's return to the consideration of the stems of twin-screw ships. As we noted above, in these ships the stern post has a more or less simple shape only if the outlet of the propeller shaft is completely unrelated to the stern post.

Consider the design of the output of the propeller shaft. The propeller shaft in this case also passes in the stern tube through the afterpeak. For small vessels, the end of the stern tube coming out of the hull is fixed on the outer skin of the vessel in a special holder (steel-cast and forged), called mortar propeller shaft. It is shown in Fig.72. The mortar of the rowing ball, being well connected with the corresponding transverse set of the vessel, is a solid support for the end of the stern tube. The ship's plating sheet covers the mortar and is fastened to it watertight by means of rivets and gougons. The propeller shaft that came out of the mortar at the place where the propeller was placed on it at the end, as mentioned earlier (see Fig. 64), is supported by a special bracket propeller shaft. This bracket, located on the outside of the boat, consists of a hub that wraps around the end of the shaft and two posts extending from the hub.

Rice. 72. Mortar propeller shaft.

These racks, if possible, go at an angle close to 90 ° to each other and are riveted to the hull of the vessel (usually over the outer skin) with the paws at their ends.

Rice. 73. Cast bracket propeller shafts.

The ship's hull in this place is properly reinforced from the inside. The lower paw rests mainly on the sole of the sternpost. In order for the bracket protruding outside the vessel to cause as little resistance as possible when the vessel moves, a streamlined section is given to its racks (such a section is given to the steering wheel we met earlier, as well as in the aircraft industry - to the wings of aircraft).

Rice. 74. Set of the stern of the vessel.

However, the same design of the outward-protruding bracket, both from this point of view and from the side of the fortress, is unacceptable for large marine two- and four-screw vessels. Therefore, in such vessels, the propeller shaft bracket, of a more solid design (in the form of special castings), is placed inside the ship's hull. For this purpose, the bracket is made of the type shown in fig. 73, cast as two branches at once for the right and left shafts, with a long enough overhang so that the propellers can fit outside the vessel in close proximity to the bracket. All the frames of the vessel going forward from this bracket are made in a special shape (see Fig. 74), due to which it is possible to lead the outer skin of the vessel up to the bracket. The ship's hull then receives a smooth ledge, visible in Fig. 63 and fig. 65, inside of which a stern tube passes and at the end of which, directly outside, a propeller is placed.

Rice. 75. View of the stern of a large twin-screw vessel.

This will always achieve a significantly better streamlining of the ship's hull in the region of the propeller shaft outlet with a very large support strength for the end of the propeller shaft. Modern large two- and four-rifle marine vessels all have this propeller shaft output. In this case, inside the ship's hull, the brackets can still get a direct connection with the stern, as can be seen in Fig. 75, which shows, together with the brackets, the sternpost of a vessel of the type that was previously shown in fig. 63.

An even more solid connection is obtained with the design of the sternpost shown in Fig. 76; the design of such a sternpost in the manufactured form is clear from Fig. 77.

Above the sternpost and rudder, the stern clearance of the vessel protrudes above the load waterline, and when cruising the stern, this clearance is submerged in the water slightly below the load waterline (Fig. 2).

Rice. 76. The design of the stern of a large twin-screw vessel.

The design of the stern clearance is also made up of frames and beams, and when cruising the stern they are usually similar to frames and beams in other parts of the vessel.

Rice. 77. Photo of the sternpost of a large twin-screw vessel.

Rice. 78. Set of the stern of the vessel.

With the usual form of the aft gap, the frames and beams are always fan-shaped ( radial or rotary), based on the transom bulkhead, as can be seen from Fig. 78. They are attached to the transom bulkhead on the knees. Through the aft gap along the transom bulkhead in the diametrical plane passes a semicircular or square vertical helminth pipe, going from below and reaching, to one of the decks of the vessel (lower or upper) in the aft gap. This pipe is carried inside the ship to this deck rudder stock, i.e., that upper, circular section, part of the rudder, which turns the rudder (using a special mechanism installed nearby on this deck).

4. Outer plating of the vessel and second bottom flooring.

The outer skin of the vessel creates the last of its waterproof shell and at the same time gives the necessary strength to the vessel. The outer skin consists of the remaining sheets riveted to the frames and stringers, and these sheets are located in their grooves along the vessel; the sheets connected by joints one with the other form going along the length of the vessel belts outer cladding. Separate belts of the outer skin have different names. The belt of the bottom, crossed by the diametrical plane, is, as we know, the name of the horizontal keel. In the presence of a bar or layered keel, a bottom belt, called sheet pile, adjoins it on one side and the other. The remaining belts of the bottom are called the bottom belts of the outer skin. Goes along the cheekbone zygomatic belt and above him row of side belts. The upper side strake adjacent to the upper continuous deck is called sheerstrake, with the strake below it often called belt below the sheerstrake. Side plating belts go further to superstructures, and the upper belt will be sheerstrecom add-ons. The belt between superstructures on board, above the upper deck, is called bulwark.

The thickness of the sheets of individual belts is taken differently: firstly, we have already seen, the horizontal keel belt is made the thickest, as well as the sheerstrake belt; bottom belts, including the zygomatic belt, have the same thickness; the side strake also have the same thickness, usually slightly less than the bottom strakes, with the exception of the strake below the sheerstrake, the thickness of which is intermediate between the thickness of the sheerstrake and the thickness of the side plating strakes. As you approach from the middle of the ship to the ends, the thickness of the sheets of each belt (outside the middle half of the ship) gradually decreases to a certain value. At the same time, however, the three belts of the bottom plating, adjacent on both sides to the horizontal keel, must retain the thickness that they have in the amidships up to the collision bulkhead. In the same way, the thickness corresponding to the thickness in the middle part must be maintained by the sheathing sheets adjacent to the sternpost and to the places where the propeller shafts exit. If cuts of considerable size are made in the ship's side plating, then these cuts must be compensated by thickening, sheathing, the introduction of overhead sheets, etc. by methods.

The thickness of all strakes of the outer plating must be increased if the ship's frame distances are increased against the normal ones. Vessels intended for navigation in ice require special thickening of the bow end sheets in the area of ​​the load waterline.

Of particular importance in relation to the longitudinal strength of the ship is the sheerstrake belt, as the most distant of all the side belts from the neutral plane of the ship. In this regard, the following feature is provided in the design of this belt. As we know, the long middle superstructure of the ship can contribute to the longitudinal strength of the ship. In the case of a long middle superstructure, its sheerstrake, being still more distant from the neutral plane than the sheerstrake of the upper deck, will take an even greater part than the latter in the longitudinal strength of the ship. From these considerations, the following is provided: with long middle superstructures, the belt near the upper deck in the superstructure area, except for its ends, does not thicken, but has the same thickness as the rest of the side belts; sheerstrake is placed at the deck of the superstructure. At the same time, the sheerstrake of the superstructure has a thickness less than would be required for the sheerstrake of the upper deck. To compensate for a sharp change in the cross section of the longitudinal hull bracing at the ends of the middle superstructure, the following fortifications are provided here: the upper deck sheerstrake does not break immediately at the superstructure, but extends beyond it for a length equal to a third of the width of the ship. At the same time, the thickness of the sheerstrake sheet of the upper deck at the ends of the superstructure is made 50% thicker than the adjacent sheerstrake sheets; this thickened sheet of sheerstrake shall extend at least 3 spacings inward and 3 spacings outward beyond the end of the superstructure.

Also, the lower cladding belt of any superstructure extends beyond the ends of the superstructure by at least 3 spacings, then smoothly passing into the bulwark belt (thinner than the superstructure plating sheets). Reinforcements similar to those indicated are also made at the ends of the long forecastle and poop (the length of which exceeds a quarter of the length of the vessel). The thickness of the outer plating of the vessel (and superstructures) is taken depending on the length of the vessel, its draft and the height of the side to the upper deck (and to the superstructure deck).

The joints of adjacent chords of the outer plating of the vessel, in order to avoid weakening the longitudinal strength of the vessel, should not be close to each other. For the spacing of the joints of the chords in the outer skin, there is the following rule: the joints of the sheets of two adjacent chords must be removed from each other by at least two spacings. The joints of the sheets of belts located through one belt should not be in the same spacing. In this case, however, the last paragraph does not apply, for the sake of the possibility of maintaining a symmetrical arrangement of joints for the right and left halves of the vessel, to sheet piling and chords adjacent to the horizontal keel. Riveting of the grooves and joints of the outer skin, as mentioned earlier (ch. Ill), is carried out with a chain seam, and the number of rows of rivets in the joints exceeds the number of rows of rivets in the grooves, especially at the bottom, sheerstrake and belt under it. To the stems, however (and to the outer keel), the skin sheets are fastened with a checkerboard seam.

The width of the plating belts: horizontal keel, sheerstrake, belt under it and bilge belt is maintained constant along the entire length of the vessel. They also try to maintain the widths of the remaining belts without large reductions in them, however, as we will see below, it is not possible to comply with this condition for all belts along the length of the vessel.

Let us first consider the very important question of the method of attaching the outer plating chords to the transverse framing of the vessel (frames and floors). The grooves of the chords of the outer skin are currently only in exceptional cases connected to the butt strips. The groove joints currently used are flush with or without flanging, and we only meet the first of these methods. With this method, either one edge of each belt (one-sided flanging) can also be flanked, or not all belts can be flanked, but through one, but in this case the flanged belt must receive flanging along both edges (two-sided) (see Fig. 79) . Double-sided flanging has production advantages, since it requires only half of all skin sheets to be fed under the machine, but from the operational side, one-sided flanging of chords has advantages, since in this case, when repairing and changing skin sheets, each sheet can be easily removed from its place. In case of double-sided flanging, the sheets of the non-flanged chord can be removed only after the sheets of one of the neighboring chords have been riveted. When using overlapping groove riveting without flanging, in order to rivet skin sheets to frames or floors, it is necessary to place a wedge gasket along the profile flange, between the sheet and the flange, as can be seen in Fig. 79. At present, a similar method of connecting the grooves is used abroad, but without a gasket, which is achieved by appropriate upsetting of the profile to which the sheet is riveted (this method of connection is shown in Fig. 80 in riveting sheets of the flooring of the second bottom to the floors); the landing of the profile is convenient for the small size of this profile. Noteworthy is the method of riveting the outer skin to the floors, shown in the same figure, where both the upsetting of the profile and the use of gaskets are avoided. True, this method has not received recognition from the classification institutions.

Rice. 79. Grooves of the side skin.

The connection of the grooves on the internal butt strips is made only in exceptional cases, when it is required to obtain a completely smooth surface at the outer skin of the vessel. This is the case, for example, with icebreakers. In this case, gaskets are also placed along the frame or floor, or the profile is subjected to landing, as indicated above.

As for the joints at the sheets of the outer skin chords, these joints occur between the frames or floors. Therefore, it is not difficult to make them both on internal butt strips and with an overlap. In the latter case, the overlap should be done in such a way that the outer cover sheet does not have an edge directed towards the bow, i.e. against the movement of the vessel.

At present, the overlapping joints of the outer skin are more often used; there are indications that such a butt weld, when stretched, retains its tightness better than a butt weld with an ordinary inner lath, while giving savings in material.

Very important in the design of the outer skin is the implementation of pairing the groove with the joint. The simplest way is to use in this place a wedge-shaped gasket along the groove shown in the race. 81.

Rice. 80. A set of flora with a planted reverse square.

However, such a design is now more often replaced by a stitching of the corresponding petting at the corner of the sheet, as seen in Fig. 82. Stitching the edge of the sheet is now used when passing the profile across the groove (or joint) of the sheet. Such a stitch is shown in Fig. 83. On it, the profile smoothly passes through the groove, requiring neither landing nor the use of a wedge-shaped gasket.

Rice. 81. Installation of a wedge-shaped gasket.

The design of the outer plating of the vessel is represented by a special drawing, in which the plating is depicted in the form of the so-called her stretch marks(see appendix 2). This stretch drawing is obtained by unrolling each frame (and floor) of the vessel into a straight line. Since the length of each of these lines depends on the contours of the hull and turns out (due to the shape of the vessel sharpening towards the extremities) of a different length of the vessel, the skin, with such a stretch, takes on a figured appearance, as can be seen from the above figure. It should be borne in mind that the skin is usually stretched, as is done in this figure, only in one direction, namely in the transverse (along the frames and floors), but not along the length (not along the waterlines). Thus, in the drawing of the outer skin, without distortion, the actual width of the sheets is given, but not their length, which in reality will be somewhat larger than it is shown in the drawing.

Rice. 82. "Weasel".

Rice. 83. Stitching a sheet.

Considering the width of the sheets of individual strakes of the outer plating, we see that due to the reduction in the contours of the vessel towards the ends, it is not possible to have all the cladding strakes of the same width in the bow and stern as they have in the middle part.

Rice. 84.

Rice. 85.

Leaving the width of the chords of the horizontal keel, sheerstrake and the chord below it unchanged, as well as the zygomatic chord, in order to obtain the required type of stretching, we would have to lead all the other chords of the outer skin to the ends gradually and evenly tapering up to the stem. Such a design, however, would be rather complicated in terms of production. Therefore, the belts of the outer skin sheets are designed somewhat differently, as can be seen in the same figure. Namely, the width of the sheets for most of the belts of the outer skin is kept unchanged. Some belts (usually a small number of them are enough for this) are made sharply tapering towards the ends of the vessel, to the point that these belts finally break off between adjacent belts adjacent to them, without bringing such tapering belts to the stems. Consequently, in some places of the skin, some belts disappear; such places are called losses these belts.

The design of losses is different and some of the most common variants of these designs are given in Fig. 84-86.

Rice. 86.

Of some interest is another feature in the design of the outer skin of the vessel. It consists in the following: in addition to the transverse bracing of the vessel, the fastening of the outer skin to which we have just considered, there are a number of longitudinal braces inside the vessel, which in some cases are also riveted to the outer skin. These bonds are usually located in such a way that the bond goes along the corresponding belt of the outer skin, without leaving it and on its way crossing only individual joints of the sheets of this belt. Such an arrangement can usually be maintained in relation to all longitudinal ties, with the exception of one - the zygomatic stringer (extreme double-bottom sheet). The zygomatic stringer, due to its position on the bilge of the vessel, on which we previously dwelled in detail, cannot go along its entire length along the zygomatic belt of the outer plating of the vessel alone. Approaching the extremities of the vessel, it begins to descend from the zygomatic belt to the adjacent belt, thus crossing the corresponding groove of these belts and, moreover, at a rather sharp angle. The passage of the lower square of the extreme bottom plate along the groove of the outer skin is in itself rather inconvenient, in this case it is further complicated by the fact that both the riveting of the groove and the riveting of the square of the bottom plate are particularly responsible in terms of their water tightness.

To obtain water tightness both along the groove and along the square, the design shown in fig. 87, where the location of the rivets in the groove and the location of the rivets in the square can be performed with the frequency required for both, ensuring their water tightness.

Rice. 87. Crossing a square with an impenetrable groove.

In addition, the very transition of the square through the protruding edge of the groove can be made conveniently feasible. With this design, the outer skin, as it is easy to see in Fig. 87, gets in the place in question salient feature in the form of a short tooth at the groove of the zygomatic girdle and at the bottom girdle adjacent to the last.

Rice. 88. Crossing a square with an impenetrable groove by welding a strip.

However, since the device of such a tooth requires significant trimming of the sheet, then in recent times, in connection with the use of electric welding, very often they resort to a simplified design, limited, as shown in Fig. 88, by local broadening of the horizontal flange of the square of the extreme double-bottom sheet in the area of ​​​​the passage of this square along the groove. This broadening is achieved by welding small pieces of sheet to the square flange, which allows a sufficient number of rivets to be placed in this place, which ensures sufficient both the density of the groove riveting and the density of the square riveting on the outer skin.

With that said, we will end our consideration of the ship's outer plating.

Device flooring of the second bottom facilitated by the fact that, as mothers know, the surface of the second bottom is usually horizontal. We have already dwelled earlier on the device of the extreme double-bottom sheet and its features. The remaining sheets of flooring are laid, as a rule, along the vessel, forming a series of belts. At the extremities, where the width of the second bottom decreases, the belts adjacent to the extreme interbottom sheet are cut at an angle, along the direction of the interbottom sheet, to form a seam with this sheet.

In the diametrical plane of the ship, along the entire deck, there is a middle belt, the thickness of which is taken greater than the thickness of the remaining belts. In general, the thickness of the sheets of both those and other belts is assigned depending on the length of the vessel and the distance between the frames.

In the area of ​​the engine room, all flooring sheets should have a thickness equal to the thickness of the middle chord; in the area of ​​​​the boiler room, all sheets receive an even greater increase in their thickness. In the same way, those sheets of steel flooring of the second bottom in the cargo holds, which fall under the clearance of cargo hatches, are thickened, if these sheets are not protected by additional wooden flooring placed in the hold over the steel one. A special thickening of the flooring sheets is done in engine room in those cases when the ship's engine frame is installed directly on the deck of the second bottom without a special foundation for the engine on the deck.

In places where the transverse bulkheads of the ship pass along the decking of the second bottom, it is allowed, as an exception, to place flooring sheets under the bulkhead - across the ship, and, however, the middle chord and the extreme double-bottom sheet should also maintain their longitudinal position in this place. The transverse arrangement of the flooring sheets under the bulkhead gives production advantages when setting the lower lining square of the bulkhead.

Flooring sheets of the second bottom are almost always connected with a lap, and usually with their flanking; along with this, the possibility of using other methods of connection, including the one shown earlier in fig. 80.

The joints of the flooring sheets are made stronger than the grooves. The foregoing applies in particular to the joints of the middle belt and the extreme double-bottom sheet. The joints of the grooves and joints have the design mentioned earlier when considering the outer skin of the vessel.

Rice. 89. The layout of the steel deck flooring.

For access to the double-bottom space in the flooring of the second bottom, manholes are arranged, at least 2 in number for each separate compartment of the double bottom, and, if possible, they should be located at opposite ends of the compartment. The dimensions of the necks should be sufficient for the convenience of crawling through them. The mouths are closed with special waterproof covers. The dimensions of the necks (as well as the design of their lids) are standardized. Covers must be protected from the possibility of damage when loading heavy cargo into the hold.

(1) There are designs in which the base of the stem also consists of a rectangular bar riveted to the skin with squares. Editor.

(3) The design of the stern tube is such that it does not allow outboard water to penetrate through it into the vessel while the propeller shaft freely exits through it (due to the stuffing box packing system) and rotates freely in it.

nasal and aft end the ship's hulls limit and reinforce the stem and stern, respectively. The stem and sternpost (Fig. 5.24, 5.25) are connected by welding to the outer skin, with a vertical and horizontal keel, high floors, side stringers, platforms. Thus, it is formed strong construction, capable of absorbing significant loads that occur during the operation of the vessel (impact on ice, floating objects, touching the berth and other vessels, loads from a working propeller, etc.).

Since the bow and stern ends of the vessel experience significant additional loads from wave impacts, the so-called. "slamming", these areas of the vessel are reinforced by reducing the spacing, additional side and bottom stringers, platforms, high floors, frame frames.

Fig.5.24. The stem is welded.

1 - breshtuk, 2 - longitudinal stiffener

SHIP DEVICES

anchor device

The anchor device is designed to ensure reliable anchorage of the vessel in the roadstead and at depths up to 80m. The anchor device is also used for mooring and unmooring, as well as for quickly discharging inertia in order to avoid collision with other ships and objects. The anchor device can also be used to refloat the vessel. In this case, the anchor is brought on the boat in the right direction and the vessel is pulled to the anchor with the help of anchor mechanisms. In some cases anchor device, as well as its elements, can be used to tow the vessel.

Marine vessels usually have a bow anchor device (Fig. 6.1), but some ships also have a stern one (Fig. 6.2).

Anchor device usually includes the following elements:

- anchor, which, due to its mass and shape, enters the ground, thereby creating the necessary resistance to the movement of the ship or floating object;

- anchor chain, which transmits force from the vessel to the anchor on the ground, is used to recoil and raise the anchor;

- anchor hawse, allowing the anchor chain to pass through the elements of the hull structures, directing the movement of the ropes when the anchor is released or selected, the anchors are retracted into the hawse for storage in the stowed position;

- anchor mechanism, providing return and lifting of the anchor, braking and locking of the anchor chain when anchored, pulling the vessel to the anchor fixed in the ground;

- stoppers, which serve to fasten the anchor in the stowed position;

- chain boxes for placing anchor chains on the ship;

- mechanisms for fastening and remote recoil of the anchor chain, providing fastening of the root end of the anchor chain and its quick return if necessary.

Anchors depending on their purpose, they are divided into deadlifts designed to keep the ship in a given place, and auxiliary- to keep the vessel in a given position while anchored at the main anchor. Auxiliary ones include a stern anchor - a stop anchor, the mass of which is 1/3 of the mass of the anchor and verp - a light anchor that can be brought aside from the vessel on a boat. The mass of the verp is equal to half the mass of the stop anchor. The number and weight of dead anchors for each ship depends on the size of the ship and is selected according to the Rules of the Register of Shipping.

The main parts of any anchor are the spindle and paws. Anchors are distinguished by mobility and the number of paws (up to four) and the presence of a stock. Legless anchors include dead anchors (mushroom-shaped, screw, reinforced concrete) used in the installation of floating lighthouses, landing stages and other floating structures.

There are several types of anchors that are used on marine vessels as anchors and auxiliary anchors. Of these, the most common are the anchors: Admiralty (previously used), Hall (obsolete anchor), Gruzon, Danforth, Matrosov (installed mainly on river boats and small sea vessels), Boldt, Gruzon, Cruson, Union, Taylor, Speck, etc.

The Admiralty anchor (Fig. 6.3a) was widely used in the days of the sailing fleet, due to the simplicity of its design and large holding force - up to 12 anchor weights. When pulling the anchor, due to the movement of the vessel, the rod lies flat on the ground, while one of the paws begins to enter the ground. Since there is only one paw in the ground, when the direction of the chain tension changes (the vessel yaws), the paw practically does not loosen the soil, and this explains the high holding force of this anchor. But it is difficult to remove it in a stowed manner (because of the stock, it does not enter the hawse and it has to be removed to the deck or hung along the side), in addition, in shallow water, a paw sticking out of the ground is a great danger to other vessels. Anchor chain can get tangled behind it. Therefore, on modern ships, Admiralty anchors are used only as stop anchors and verps, with occasional use of which its disadvantages are not so significant, and a high holding force is necessary.

The Hall anchor (Fig. 6.3 b) has two swivel legs located close to the stem. When the vessel yaws, the paws practically do not loosen the soil, and therefore the holding force of the anchor increases to 4-6 times the gravity of the anchor.

The Hall anchor meets certain requirements: 1) it is quickly released and conveniently fastened in a stowed position; 2) has sufficient holding power with less weight; 3) quickly picks up the soil and easily separates from it.

The anchor consists of two large steel parts: a spindle and paws with a head, connected with a pin and locking bolts.

This anchor does not have a stem, and when harvesting, the spindle is drawn into the hawse, and the paws are pressed against the body. Among the large number of anchors without a stem, the Hall anchor compares favorably with a small number of parts. Large gaps at the joints of the parts exclude the possibility of jamming of the paws. When falling on the ground, thanks to the widely spaced paws, the anchor lies flat and, when broached, the protruding parts of the head part make the paws turn towards the ground and enter it. Burrowing into the ground with both paws, this anchor does not pose a danger to other vessels in shallow water and the possibility of entangling the anchor chain for it is excluded. But due to the fact that two widely spaced paws are in the ground, when the vessel yaws, the ground is loosened and the holding force of this anchor is much less than that of the Admiralty with one paw in the ground.

The Danforth anchor (Fig. 6.4) is similar to the Hall anchor, it has two wide, knife-shaped swivel legs located close to the stem. Due to this, when the vessel yaws, the paws practically do not loosen the soil, increasing the holding force up to 10 times the gravity of the anchor and its stability on the ground. Thanks to these qualities, the Danforth anchor has received the widest distribution on modern marine vessels.

Fig.6.4. Dumfort Anchor

Matrosov's anchor has two swivel legs. In order for the anchor to lie flat on the ground in all cases, there are rods with flanges in the head of the anchor, and after being pulled by the vessel, the anchor lies flat and, thanks to the protruding parts of the head, the paws turn and enter the ground. Yako Matrosov is effective on soft soils, so it has become widespread on river and small sea vessels, and its large holding force allows to reduce weight and make the anchor not only cast, but also welded.

On small ships and barges, multi-armed rodless anchors, called cats, are used. Ice navigation vessels are equipped with special single-legged rodless ice anchors designed to hold the vessel near the ice field.

anchor chain serves to fasten the anchor to the hull of the vessel. It consists of links (Fig. 6.5) that form links connected to one another with the help of special detachable links. The bows form an anchor chain with a length of 50 to 300 m. Depending on the location of the bows in the anchor chain, anchor (attached to the anchor), intermediate and root bows (attached to the ship's hull) are distinguished. The lengths of the anchor and root bows are not regulated, and the length of the intermediate bow, which has an odd number of links, is 25–27.5 m. Anchor is attached to the anchor chain with an anchor shackle. To prevent twisting of the chain, swivel links are included in the anchor and root bows.

Anchor chains are distinguished by their caliber - the diameter of the cross section of the link bar. Chain links with a caliber of more than 15 mm must have spacers - buttresses. For the largest ships, the caliber of anchor chains reaches 100-130mm. To control the length of the etched chain, each bow at the beginning and end has a marking indicating the serial number of the bow. Marking is done by winding annealed wire on the buttresses of the corresponding links, which are painted white.

Anchor hawses perform two important functions on ships - they provide unhindered passage of the anchor chain through the hull structures during the release and selection of the anchor and provide convenient and safe placement of the rodless anchor in the stowed position and its quick release. Anchor fairleads consist of a hawse pipe, a deck hawse and a side hawse.

The hawse pipe is usually made of steel welded from two halves (in diameter), and the lower half of the pipe is thicker than the upper one, since it is subjected to greater wear by the moving chain. The inner diameter of the pipe is taken equal to 8-10 chain gauges, and the wall thickness of the lower half of the pipe is in the range of 0.4-0.9 chain gauge.

Side and deck closures are cast steel and have thickenings in the places where the chain passes. They are welded to the hawse pipe and welded to the deck and side. Anchor spindle in a stowed way enters the pipe; only the legs of the anchor remain outside.

To prevent water from entering the deck through the fairleads, the deck fairlead is closed with a special hinged lid with a recess for the passage of the anchor chain.

To clean the anchor and chain from dirt and bottom soil with water when choosing, a number of fittings connected to the fire main are provided in the hawse pipe.

On passenger and port ships, anchor hawses are often made with niches - welded steel structures, which are recesses in the sides of the vessel, into which the anchor paws enter. An anchor drawn into such a hawse does not protrude beyond the plane of the side outer skin. These fairleads have a number of advantages, the main of which are the following: reducing the possibility of damage to ships during mooring operations, towing and movement in ice, as well as improving the fit of the legs to the outer skin by changing the slope of the inner surface of the fairlead.

Protruding Clus shown in Fig. 6.6 b, where its difference from the usual clus is clearly visible. Protruding hawsers are used on vessels with a bulbous bow shape, which makes it possible to exclude the impact of the anchor on the bulb during its return.

Open Cluses, which are a massive casting with a chute for the passage of the anchor chain and the anchor spindle, are installed at the junction of the deck with the board. They are used on low-sided ships, on which conventional hawses are undesirable, since water gets on the deck through them on waves.

Anchor mechanisms serve to release the anchor and anchor chain when anchoring the vessel; stopping the anchor chain when the vessel is at anchor; anchoring - pulling the vessel to the anchor, hauling the chain and anchor and pulling the anchor into the hawse; mooring operations, if there are no mechanisms specially provided for these purposes.

The following anchor mechanisms are used on sea vessels: windlasses, half windlasses, anchor or anchor-mooring capstans and anchor-mooring winches. The main element of any anchor mechanism working with a chain is a chain cam sprocket drum. The horizontal position of the sprocket axis is typical for windlasses, the vertical position for capstans. Some modern ships(for a number of reasons) conventional windlasses or capstans are not practical. Therefore, anchor-mooring winches are installed on such vessels.

Windlass Designed to serve both left and right side chains. On large-tonnage vessels, half windlasses are used, offset to the sides. The windlass consists of an engine, a gearbox and chain sprockets and turrets placed on the cargo shaft (mooring drums for working with mooring lines). The sprockets sit freely on the shaft and can only rotate when the engine is running when they are connected to the load shaft by special cam clutches. Each sprocket is equipped with a pulley with a band brake. Windlasses provide joint or separate operation of sprockets of the left and right sides. The use of friction clutches allows you to soften shock loads and ensure smooth inclusion of sprockets. The anchor is released at shallow depths due to its own mass and the mass of the chain. The speed is controlled by the windlass band brake. On the great depths the chain is etched using a windlass mechanism. Turachki sit rigidly on the cargo or intermediate shaft and always rotate when the engine is on. In the bow anchor device, both sprockets and mooring drums have one drive.

The capstan mechanism is usually divided into two parts, one of which, consisting of a sprocket and a mooring drum, is located on the deck, and the other, including a gearbox and engine, is located below deck. The vertical axis of the sprocket allows unlimited variation in horizontal plane direction of chain movement; along with good looks and a slight clutter on the upper deck, this is a significant advantage of the spire. Often the anchor and mooring mechanisms are combined in one anchor-mooring capstan.

Anchor-mooring winches. Currently in anchor device

Fig. 6.11. Anchor-mooring winch (half windlass with mooring drum). Scheme.

large-capacity vessels began to use anchor-mooring winches with hydraulic drive and remote control. These winches are composed of half windlasses and automatic mooring winches, which have a single drive. Anchor-mooring winches can serve an anchor device with a chain gauge up to 120 mm. They are characterized by high efficiency, less weight and safety in operation.

Anchor mechanisms can be steam, electric or hydraulic driven.

Stoppers are designed to fasten anchor chains and hold the anchor in the hawse in the stowed position. To do this, use screw cam stoppers, stoppers with a mortgage link (mortgage stoppers) and for a tighter pressing of the anchor to the hawse - chain stoppers.

Mortgage stopper (Fig. 6.12) consists of two fixed cheeks, allowing the chain to freely pass between them along the recess corresponding to the shape of the lower part of the vertically oriented link. On one of the cheeks, a mortgage fell is fixed in the slot, which freely enters the cutout of the opposite cheek. The inclination of the notch is such that the force generated by the locked chain completely absorbs the fall. This stopper is recommended for chains over 72mm.

In a screw stopper, the base is a plate, in the middle part of which a groove is made for the passage of chain links. On small vessels, a horizontally oriented link is pressed against the base plate with two cheeks. The cheeks are hinged and driven by a screw with opposite trapezoidal threads. AT open position the slaps allow the chain to slide freely along the groove of the base. To prevent the chain from damaging the screw during movement, the stopper has a limiting arc. The chain locking occurs as a result of the action of friction forces when the chain link is pressed against the stopper plate by the cheeks. On large vessels (with a large caliber of the chain), this method fails to provide the necessary force to lock the chain. Therefore, between the two vertically. located links are introduced cams located on the cheeks with a similar stopper scheme.

13-

11-1

Fig. 6.12. Design of anchor chain stoppers: a- mortgage, b-screw, in - chain.

1 - base plate; 2- mortgage fell; 3 - cheek; 4 - gutter; 5 - pin; 6 - arc; 7 - screw; 8 - slap; 9 - handle; 10 - chain; 11 - lanyard; 12 - butt; 13 - verb-gak.

The chain stopper is a short chain bow (smaller caliber) passed through the anchor bracket and which is fixed with its two ends to the butts on the deck. With a lanyard included at one end. chains, pull the anchor into the hawse until the paws fit snugly against the outer skin. The verb-hook, included at the other end of the chain, serves to quickly release the stopper. The windlass (spire) band brake is used as the main stopper when the vessel is at anchor. Such locking has a number of advantages, among which the most important is the possibility of releasing the chain due to slipping of the brake pulley relative to the brake band during jerks.

Chain pipe (deck hawse) serves to guide the anchor chain from the deck to the chain box. The chain pipe has sockets in the upper and lower parts. Chain pipes are placed vertically or slightly inclined so that the lower end is above the center of the chain box. When installing the windlass, the upper bell of the chain pipe is attached to its foundation frame. When installing the spire, an angular rotary bell is used, which consists of a cast body and a cover hinged in its upper part. The lid closes the socket, protecting the chain box from water ingress into it, and allows, if necessary, to keep a section of the anchor chain on the deck for inspection, for which it has a hole corresponding to the chain link.

The length of the chain pipe depends on the location of the chain box along the height of the vessel. The inner diameter of the pipe is taken equal to 7–8 chain gauges.

chain boxes are intended for placement and storage of anchor chains. When selecting anchors, the chain of each anchor is placed in the compartment of the chain box reserved for it.

The dimensions of the chain box must ensure self-laying of the anchor chain when the anchor is hauled out without pulling it apart manually. This requirement is met by cylindrical compartments of the chain box with a diameter equal to 30–35 chain gauges (in any case, the box should be relatively narrow). The height of the chain box should be such that the fully laid chain does not reach the top of the box by 1–1.5 m. A powerful semi-oval eye, through which the anchor chain, changing direction, is brought to the attachment of the root end. The chain box has self-draining.

Fastening and return of the anchor chain. In the upper part of the chain box there is a special device for fastening and emergency return of the root end of the anchor chain. The need for quick return may arise in the event of a fire on a neighboring vessel, a sudden change weather conditions and in other cases when the ship must quickly leave the anchorage.

Until recently, the attachment of the root bow to the body was carried out by zhvako-tack - containing the verb-gak. The return of the chain was made only from the chain box.

At present, to return the anchor chain, instead of the verb-hook, which is unsafe when the chain is released, they began to use folding hooks with a remote drive. The principle of operation of the hinged anchor hook is the same as the verb-hook, with the only difference being that the hinged hook stopper is released using a remote roller or other drive. The control of this drive is located on the deck directly at the anchor mechanism.

The fore and aft ends of the ship's hull are limited by the stem and stern, respectively, which are securely connected to the plating of the starboard and port sides, vertical keel, side stringers and decks.

Rice. 45. Welded stem.

1 - breshtuki; 2 - longitudinal stiffener

stem(Fig. 45) takes on impacts in collisions with other vessels, on the ground, pier, ice. The stems are cast, forged, welded from cast and forged parts and, most often, welded from bent steel sheets. The stem of a large vessel is divided in height into several parts, which are interconnected “in a lock” using arc or slag bath welding. The sheathing sheets adjacent to the stem are welded with a fillet weld.

Decks and side stringers reaching the stem are welded to the horizontal ribs of the stem - breshtuk- triangular or trapezoidal sheets reinforcing bent stem sheets. In the underwater part, the breshtuki are installed at least every 1 m, above the waterline - at least every 1.5 m. The vertical keel is welded to the longitudinal stiffener of the stem. The dimensions of the section of a cast stem or the thickness of a welded stem from sheets are determined in accordance with the Register Rules.

Akhtershteven(Fig. 46) - a powerful cast or welded structure that completes the aft end of the hull. On single-screw ships, the sternpost serves as one of the supports for the stern tube, which passes through a hole in the sternpost apple, located in its front rack, called starnpostom. The sternpost also serves as a support for the steering wheel, which rotates on pins connected to its vertical strut - ruderpost. Starnpost and ruderpost are connected in the upper part by an arch, and in the lower part - sole, thus closing stern window.

Rice. 46. ​​The sternpost of a single-rotor ship.

1 - starnpost; 2 - apple; 3 - sole; 4 - heel; 5 - ruderpost; 6 - steering wheel loop;

7 - window; 8 - arch

Rice. 47. The stern of a vessel with an “open” type stern

On some ships with a semi-balanced steering wheel, the rudder post is a bracket that is not connected to the star post at the bottom (Fig. 47). A similar stern post forms an “open” type stern, so named because of the lack of a stern post window (the propeller operates in an open space).

Sternposts are cast, welded from cast and forged parts and welded from sheets. The mass of cast sternposts of large ships reaches 60-180 tons, so they are made from several welded parts. A strong connection of the sternpost with the main hull structures is achieved by welding them with the stiffening ribs of the sternpost. The sternposts of ice-going ships, which, as a rule, have a cruising stern with sharp formations to protect the rudder and propeller, must have an ice outlet located aft of the rudder, i.e., a structure made of steel sheets with reinforcing ribs that protects the rudder from damage.

Rice. 48. Two-legged propeller shaft bracket.

propeller shaft brackets(Fig. 48) - these are support structures for side propeller shafts of two-, three- and four-screw vessels. Brackets are mainly cast and, less often, welded, single-legged and double-armed. The cross-sectional area of ​​each leg of the two-legged bracket is taken equal to at least 60% of the cross-sectional area of ​​the propeller shaft. The paws of the two-legged brackets are positioned relative to each other at an angle close to 90°. The axial lines of the legs must intersect on the axis of the propeller. The paws are attached to the hull set and outer skin by welding or riveting. In this case, the cross-sectional area of ​​the weld or the cross-sectional area of ​​the rivets fastening each leg must be at least 25% of the cross-sectional area of ​​the shaft.

The shape of the stem depends on the shape of the bow of the vessel (Fig. 1). Previously, ships were built with a vertical stem, and at present, the stem slope to the vertical is 10-20 °. Vessels intended for navigation in ice have a stem with a large undercut in the underwater part. The angle of inclination of the stem to the horizon on icebreakers is 20-30°, and on ice-going transport ships 40-50°. This shape allows the icebreaker to crawl onto the ice. To increase the speed in the underwater part of the stem, a drop-shaped thickening is made - a bulb, which reduces the resistance of water to the movement of the vessel.

Rice. 1 The bow of the ship: a - straight; b - inclined; c - icebreaking; g - bulbous

The stem (Fig. 2) can be made in the form of a bar of rectangular or trapezoidal section. For connection with a horizontal keel, the stem section in the lower part gradually changes into a trough-shaped form. Recently, welded stems made of sheet steel have been widely used. The stem, curved from a thick sheet, is supported along the entire height by large horizontal knees - breshtuks.

Rice. 2 Stem: a - bar (forged); b - leaf (svrioy); 1 - breshtuki

The sternpost (Fig. 3) of a single-screw vessel with an unbalanced rudder is a frame consisting of two branches, the front one is the star post and the rear one is the rudder post. A protected space is formed between them - an embrasure in which a propeller is placed. The starn-post has a thickening with a through hole (the apple of the starn-post) for the propeller shaft exit. The ruderpost is equipped with hinges for hanging the steering wheel, which have through cylindrical holes, in the lower hinge - the thrust bearing - there is a blind hole, where a bronze or back-out bushing is inserted. The heel of the steering wheel in the thrust bearing rests on a hardened steel lentil.

Rice. 3 Akhtershteven: 1 - ruder post; 2 - starn-post; 3 - apple starn-post; 4 - thrust bearing; 5 — steering loops; I - hinge, II - thrust bearing

On twin-propeller ships, the stern post does not have a star post and consists only of a rudder post on which the rudder is hung. On ships with balance rudder, the sternpost does not have a rudder post.

The sternpost of marine vessels has a rather complex shape and design and is more often cast with separate forged parts.

The upper part of the stern of modern ships usually looks like a flat vertical surface. This is a transom feed.

The propeller shaft on single-screw ships goes out through the stern tube (Fig. 4), which is attached to the afterpeak bulkhead with the bow end using a flange, the stern end passes through the starn-post apple and is fixed with a nut. The stern tube to the after peak bulkhead and the star post can also be attached by welding.

In the stern tube, the propeller shaft rests on bearings. As stern tube bearings, plain bearings with bushings from backout are used. Backout strips 1-1.5 m long are collected in a bronze bushing, which is pressed into the stern tube. A small gap is left between the strips through which outboard water enters to lubricate and cool the bearing. So that water from the stern tube does not penetrate inside the body, a stuffing box is installed at the bow end of the pipe.

Rice. 4 Stern tube: a - longitudinal section; b - stern tube with a set of liners from backout; 1 - starn-post; 2 - stern tube; 3 — aft stern tube; 4 - bow stern tube; 5 - gland packing; 6 - afterpeak bulkhead; 7 - gasket; 8 - stern tube flange; 9 — the pressure plug of an epiploon; 10 - propeller shaft; 11 - bushings of the stern bearing

For a set of stern tube bearings, instead of a backout, its substitutes are used:

• Rubber-metal strips;
• Wood laminate;
• Textolite;
• Kaprolon.

Recently, the number of ships with stern tube bearings made of babbitt has increased significantly. These bearings require pressurized oil lubrication, so a special stuffing box must be fitted at the aft end of the stern tube.

On twin-screw ships, the propeller shafts go out through the mortar - a short pipe firmly fastened to the hull. It has a stern tube bearing that supports the propeller shaft, and an oil seal that prevents water from entering the vessel's hull.

After exiting the mortar, the propeller shaft is pulled a certain length aft and directly at the propeller is supported by a bracket. On high-speed vessels and ice-going vessels, frame fillets are often arranged instead of a bracket. In this case, the contours of the aft part of the ship are shaped so that the propeller shafts can remain inside the ship's hull all the way to the place where the propellers are installed.