Differences of yachts in the shape of the hull

Sailing yacht classification

The main parts of the yacht

A yacht is any vessel, whether motorized or sailing, intended for sporting or tourist purposes. A sailing yacht has two main parts: the hull and the rig. The hull is designed to accommodate the crew and supplies of the yacht. Armament is understood as sails and all devices for setting sails and controlling them.

Consider the main parts of the hull of a sailing yacht (Fig. 1). The front of the hull is called the bow , the back is called the stern . The parts of the hull hanging over the water are called bow and stern overhangs ; side surfaces of the hull – sides . The starboard and port sides are determined when viewed from stern to bow. The lower surface of the hull is called the bottom , the transition from the side to the bottom is the cheekbone . The rear edge of the hull is called a transom , the surface of the aft overhang facing the water is a valance . From above, the hull is closed by a deck that protects the vessel from water ingress. A deck is generally any flooring that covers any room below. The fore part of the deck is called the tank , the stern part is the poop , the middle part is the quarterdeck *.

Cutouts are made in the deck to accommodate the crew – cockpits. Cockpits are open when they are not fenced off from the underdeck space, and closed. In the latter case, they are a box inserted into the deck cutout and isolated from the space below deck. An enclosed cockpit is usually made self-draining by placing its floor above the waterline and equipping it with drain pipes. Through these pipes, water that has entered the cockpit from the deck is drained overboard. Self-draining cockpits are found on marine yachts, which can get on the deck of large amounts of water, as well as on modern racing dinghies. True, in the latter, a self-draining cockpit has a drain of water not through pipes, but through a valve or simply holes in the transom cut at the level of the cockpit blind floor.

The lower part of the deck space, located under the floor of the cabin or cockpit, is called the hold. The hold is closed with a flooring, which is called sleigh or payol. The transverse bulkheads (walls) divide the hull of the yacht into rooms – compartments.

Living quarters on a yacht are called cabins; the cabin, located under the tank, is the cockpit, the extreme bow and stern compartments of the hull are, respectively, the forepeak and afterpeak.

Openings in the deck for communication with the underdeck space are called hatches. There are entrance and light (light) hatches, the covers of which are usually glazed.

If the height of the underdeck space is insufficient, then superstructures are made on the deck. The superstructure above the cabin is called the wheelhouse. Windows are cut out in the walls of the cabin (coamings) – portholes.

Household premises on a yacht, as well as on a large ship, have their own names: kitchen – galley, restroom – latrine.

The steering wheel is turned by a tiller to steer the yacht. The part of the rudder to which the tiller (or other steering gear) is attached is called the rudder head .

Rice. 1. Keel yacht and its parts: 1 – bow overhang; 2 – keel; 3 – hold; 4 – rudder blade; 5 – aft overhang; 6 – valance; 7 – transom; 8 – yut; 9 – cockpit; 10 – felling; 11 — entrance hatch; 12 – cabin; 13 – deck; 14 — light (light) hatch; 15 – railing, 16 – bow to the stern railings; 17 – anchor device (anchor, day, biteng “deck clewse), 18 – tank; 19 – cockpit; 20 – forepeak; 21 – compass.

The main parts of the armament of the yacht are sails, spars and rigging. Sails are the main propulsion of the yacht. They are divided into three sets: main (or tacking), additional and storm sails.

The yacht carries the main sails in normal voyages. The same sails determine the measured sail area of the yacht.

Racing requires special sails that increase the sail area in some situations that occur on the course (for example, with fair winds). Such sails are called additional.

When sailing in stormy weather, tacking sails are replaced by smaller and more durable storm sails.

The totality of all wooden or metal parts of weapons that serve to fasten and carry sails is called a mast.

Rigging – gear made of vegetable or steel cable – is divided into standing and running. Standing rigging is used to brace and maintain the spars in the working position, and running rigging is used for setting and cleaning sails and spars, controlling sails, for raising and lowering signals.

We will dwell on the arrangement of sails, spars and rigging in detail in the section “Arrangement and armament of a yacht”.

* The name “shkantsy” is not customary to use on small yachts, but on yachts over 14-15 m long it is quite appropriate.

Types of sailing yachts

In the practice of sailing, yachts of various types and sizes are used. Depending on the navigation conditions in a particular area, larger or smaller yachts of one design or another are used. The type of yacht is primarily determined by its purpose and area of navigation, as well as the design of the hull and armament.

On this basis, cruising and racing yachts are distinguished. The main purpose of racing yachts is sailing races over limited distances, so they are built as light as possible. For long-distance voyages, they are not strong enough and do not have amenities.

Cruiser yachts, on the contrary, have a very solid construction and a maximum of domestic amenities, that is, they meet their main purpose – cruising and racing on the high seas with a large distance from the base.

In modern sailing, purely cruising yachts are not common. There are a large number of yachts for participation in offshore races, which are called cruising and racing. Such yachts are also suitable for long-distance voyages, up to ocean ones.

Cruising and cruising-racing yachts are equipped with the necessary navigational equipment and, as a rule, an auxiliary engine.

In addition to such a general classification, there is also a sports classification of yachts, which determines their division into classes.

The sports classification of yachts is necessary to create equal conditions for sports competition in racing. Within each class, as far as possible, equal chances of winning the competition (to the extent that these chances are determined by the boat itself) are ensured.

In each class, the shape and dimensions of the yacht are more or less limited so that the yachts of this class have as much speed as possible and the best seaworthiness.

Differences of yachts in the shape of the hull

The design features of the hull of a sailing yacht are determined by the use of a sail on it as the main mover.

Rice. 2. The effect of the wind on the sails of a yacht sailing with a tailwind

Imagine that the wind blows directly into the stern of the yacht ( Fig. 2 ). Jets of air, running into the sail, create a certain pressure on its windward side. Rounding the sail, the jets tend to go further (along with all the moving air), as a result of which a certain rarefaction is created on the leeward side of the sail. As a result of the simultaneous pressure on the windward side of the sail and rarefaction on its leeward side, a force of wind pressure on the sail arises. It is she who pulls it, and with it the yacht in the direction of travel (if the sail is as shown, perpendicular to the wind). This is the simplest case.

Rice. 3. The action of the wind on the sails of a yacht sailing at an acute angle to the wind

Another thing is when the yacht is sailing in such a way that the wind blows at an angle to the direction of its movement ( Fig. 3 ). Then the force R of the wind pressure on the sail, obviously, will not coincide with the direction of the yacht. Experimentally found that it is directed approximately perpendicular to the plane of the sail.

This force will cause not only the movement of the ship forward, but also to a large extent drifting to the side, or, as they say, drifting to the wind.

It is possible to decompose the force R according to the parallelogram rule into two forces directed respectively in the direction of the yacht’s movement and perpendicular to it. The force T obtained as a result of decomposition will pull the vessel in the direction of its movement. They call it traction force. The force D causes the ship to drift (drift) to the side and is therefore called the drift force. The presence of these two forces, resulting from the pressure of the wind on the sails, determines the features that we have already talked about. Indeed, other types of ships (steam, motor, towed) do not normally have the drift force caused by their propulsion.

As seen in fig. 3 , the drift force is significant compared to the thrust force. Why does the yacht not go in the direction of the force R, as one would expect at first glance?

The resistance of any ship in the direction of movement is much less than the resistance to movement in the transverse direction. Therefore, despite the fact that in this case the thrust force is less than the drift force, the forward speed of the ship is still greater than the drift speed. However, an ordinary vessel, such as a powerboat, will be able to sail more or less well only with fair winds, when the drift force is relatively small compared to the traction force, since the lateral resistance is not enough. In order for the ship to sail well with such a wind direction, as shown in fig. 3 , it must have a sufficiently large lateral resistance. In sports sailing vessels, this is achieved with the help of vertical fins placed under the bottom of the yacht along the hull.

In addition, the drift force causes the yacht to roll, and in order to counteract this roll, any sailing vessel must have great stability, that is, the ability to resist roll. A feature of a sailing ship is that it almost always goes with a roll, sometimes reaching 30-40 °.

These two provisions determine the main difference between the hulls of sailing yachts – the difference in the way they deal with drift and roll.

Rice. 4. Keel yacht

The most characteristic and common type of sailing yacht is the keel yacht. The hull shape of a typical keel yacht is shown in fig. 4. The bottom of the hull passes into a deep fin, which creates significant lateral resistance. To give greater stability, a cast-iron or lead weight, called a ballast keel or false keel, is attached to the bottom of this fin . Yachts of this type are designed for sailing on the seas and lakes with deep water and strong winds and waves. A keelboat is very stable and cannot capsize under normal conditions. True, such a danger arises when the yacht goes along the crest of a large ocean wave (as they say, lag to the wave). So it was, for example, with the yacht of F. Chichester during his circumnavigation. But even with such an incident, the keel yacht will still be on an even keel if it has a good waterproof deck and closed hatches. It is difficult to sail on keel yachts along rivers and shallow lakes due to the large draft.

Rice. 5. Dinghy

Dinghys ( Fig. 5 ) have a shallow-draft and relatively wide hull. A slot is made in the middle of the hull, in which a flat (metal or wooden) retractable keel – centerboard is placed. The slot for the passage of the daggerboard is surrounded by a wooden or metal box – a daggerboard well, the upper cut of which is located above the waterline. When there is no need for additional lateral resistance (for example, with tailwinds) or when a shallow place is passed, the daggerboard can be raised and even completely removed into the daggerboard well.

The stability of a dinghy is much less than that of a keel yacht, and is mainly ensured by the corresponding shape of the hull—flat and wide. However, modern racing dinghies successfully race in difficult sea conditions, with stormy winds and large waves. Still, cruising on the high seas and on large lakes in cruising dinghies is risky and generally not allowed.

There are also intermediate types of yachts that combine the characteristics of the described vessels. So, to obtain increased stability with a small draft, ships are built with a centerboard passing inside the ballast keel ( Fig. 6 ). These vessels have less draft without a centerboard than keel yachts, but more than dinghies. Such yachts are called compromises.

rice. 6. Yacht-compromise

Previously, compromises were used mainly as cruising yachts in areas where there are significant open water areas with strong winds, but with low water, as well as for combined navigation, when you have to often go from the river to the sea, canal, reservoir, etc. However in recent years there have been many cruiser-racing compromises for sea and even ocean navigation, in which the centerboard is placed to control the lateral drag of the yacht.

In the most recent years, yachts have appeared that have a completely “marine”, heavy and durable design, equipped with the same well as the dinghies, with the only difference being that a heavy ballast fin profiled in the form of an airplane wing moves vertically in this well. Naturally, to lift such a “daggerboard”, special power drives are required, for example, hydraulic ones. Such yachts, according to the international rules for measuring cruising and racing yachts, are called yachts with “falling” keels.

So far we have been talking about yachts with one hull. However, there are also multihull yachts – catamarans and trimarans.

Catamarans ( Fig. 7 ) have two identical long narrow hulls separated by such a distance as to ensure greater stability. The resistance of such hulls is much less than the hulls of a conventional yacht, so the catamaran develops much higher speeds than the fastest racing dinghies. They also make cruising catamarans, on which they successfully make ocean voyages at very high average speeds (10-15 knots).

Trimarans ( Fig. 8 ) have three hulls: a middle hull (wider than that of catamarans, but much narrower than that of yachts) and two spaced and slightly raised side hulls, very narrow. The side cases are essentially floats,

Rice. 7. Racing catamaran class “B”

providing stability. When heeling, the trimaran goes on the middle hull and one of the side hulls. Trimarans once gained great popularity as cruising yachts, but now interest in them has largely declined. The fact is that on the wave they are rather poorly controlled, have a sharp roll and experience strong shocks that can lead to destruction. Great initial stability at small angles of heel does not protect trimarans (as well as catamarans) from rapid capsizing if wind and wave conditions (or steering errors) lead to slightly exceeding the allowable heel angles. And then it is almost impossible to put a catamaran or trimaran in the sea “on an even keel”.

Catamarans are successfully developing as very “sporty” racing vessels. However, as cruising and racing yachts, they did not live up to expectations either in terms of speed or safety. In serious ocean racing, there have been almost no major yacht accidents, let alone catastrophes, for many years. But cases of accidents and even death of catamarans and trimarans on the high seas are quite frequent. Thus, the race across the Atlantic in 1968 attracted forty-three yachts, which included eleven trimarans and four catamarans. Of the multihull yachts, only four reached the finish line, and only one catamaran was among the winners. Almost all catamarans and trimarans that left the race had more or less severe accidents, miraculously without human casualties.

All this makes one treat cruising multihulls with a certain caution, although in the transatlantic races of 1972 the trimarans performed much better, taking first, third and fifth places in this grandiose race.

The external shape of the yacht’s hull is characterized by the shape of its cross section, as well as the appearance of the bow and stern. When comparing ships, consider a section passing approximately through the middle of the yacht. It is called a section along the midsection frame or midsection.

Rice. 8. Trimaran: A – racing, B – cruising

According to the shape of the midsection, all yachts, regardless of type, are divided into yachts with a rounded midsection, or round schangout ( Fig. 9, a, b, c and d ), and with an angular midsection, or sharpie ( Fig. 9, e, f, g and h ), the shape of which is made up of straight or curved lines forming angles.

The construction of yachts with angular frames is easier and somewhat cheaper, but these yachts lose a little to round frames in appearance and speed. Therefore, racing yachts are most often built with round spanners, although there are quite a few yachts with an angular midsection that have gained great popularity (youth classes “Cadet”, “Optimist”, a yacht “Star class” and many others).

The classic shape of the midsection of a keel yacht is rounded, with a smooth transition from the bottom to the fin. Most of the more or less large keel yachts, both racing and cruising, have this shape.

Sometimes the transition from the bottom to the false keel is not smooth ( Fig. 9, c and g ), but sharp, and the false keel is attached to a wooden fin. Boats with this midship shape are called fin keel yachts. Now yachts with the so-called bulb-keel are widespread – a vertical profiled thin fin with a cigar-shaped ballast (bulb) from below. Such keels have yachts of Olympic classes

“Zvezdny” and “Tempest”, as well as many cruising and racing yachts of small size.

Dinghy boats, like keel yachts, are made with both an angular midsection ( Fig. 9, e ) and a rounded one ( Fig. 9, a ). In addition, there are dinghies with one and two dinghies.

Rice. 9. Forms of midship frames. Round frame yachts: A – dinghy; B – keel yacht with bulb keel (Tempest class); B – keel yacht with a fin keel; D – keel yacht of the usual form. Sharpie yachts: D – dinghy (class “Optimist”); E – keel yacht with bulbknlem (“Zvezdnyn class); Zh – keel yacht with a fin keel; 3 – sharpie with a cut cheekbone

In a single-dagger, the centerboard is located in the diametrical plane of the vessel. In a double-dagger, both daggerboards are set at an angle (dashed lines in Fig. 9, a ), so it resists drift somewhat better at large roll angles. With a strong roll, one of the centerboards does not work, and often completely out of the water; the second centerboard at this time is almost in a vertical position, then it takes over all the work to counter the drift.

Currently, double-screws are used very rarely.

According to the shape of the nose, yachts are traditionally divided into straight stems, yachts with a spoon-shaped stem and a clipper stem ( Fig. 11 ). However, spoon-shaped stems with a large bow overhang are now out of fashion, and most modern yachts and dinghies have bows of the type shown in fig. 11b . A straight stem in its pure form is now preserved only in some dinghies. Long-disappeared clippers ( Fig. 11, c ) nowadays appear more and more often not only on large motor and sail-motor yachts, but also on small cruisers.

In small dinghies and yacht boats (dings), the bow often ends not with a sharp stem, but with a flat inclined cut ( Fig. 10, e ). Such a nose is called a transom (sometimes pram), and the cut itself is a bow transom or fsrshpigel. The dinghies of the youth classes “Optimist” and “Cadet” have transom prows.

According to the shape of the aft part of the yacht, they can have a yacht stern with a normal or reverse (reversible) transom ( Fig. 10, a, b ), kayak ( Fig. 10, c ) or transom trimmed stern. The latter has two varieties; one of them is typical for keel yachts ( Fig. 10, d ), the other for dinghies ( Fig. 10, e ).

Rice. 10. Forms of stern parts: A – yacht stern with a normal transom; B – the same with a reversible transom; B – kayak stern; G – transom trimmed stern of a keel yacht; D – the same dinghy Rice. 11. Forms of bow parts: A – spoon-shaped stem; B – modern inclined stem; B – clipper-rod; G – straight stem; D – transom bow (forespiegel) of the Cadet dinghy

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