7. Keys

Unit 1. Type of Ships and Boats

1) How can ships in general can be classified by their use?

They can be classified by their use as Men of War or Warships and Merchant hips.

2) Why do certain types of warships tend to become obsolete or even don’t

appear?

Because of the invention of new weapons or the development of new tactics.

3) According to what criteria may the ships be classified?

They may be classified according to the following criteria:

a) If they are used for the trade, they are merchant ships and if they are used for belligerent purposes, they are warships.

b)If they are intended for the service on the sea, they are sea-going ships, and if they are intended for the service on the rivers, they are river boats.

c) If they carry the cargo, they are cargo ships, and if they transport passengers, they are passenger ships.

d)The type of cargo ships, they carry, such as: general cargo ships, bulk carriers, ore carriers, bulk/ore carriers, dry cargo ships, OBO ships, refrigerated cargo ships, containerships, oil tankers, liquefied gas carriers, LNG carriers etc.

e) The type of machinery they use for their propulsion, such as steamships, motorships and nuclear ships.

4)The ship may be built perpendicular or parallel to the water.

a) How are sea-going ships built?

b)How are river boats built?

a) Sea-going ships are built perpendicular to the water, i.e. their fore an aft line is perpendicular to the water, they are built and launched endwise.

b)The river boats are built parallel to the water, i.e. they are built broad-side and launched sideways.

5)Explain the following terms: the liners, the coasters.

The liners are the ships which keep a definite route.

The coasters are the ships whose route is along a coast.

6)The ship propelling machinery may be of different type.

Specify the types of ship propelling engines.

They are:

a) reciprocating steam engines,

b)steam turbines,

c) marine diesels (diesel engines),

d)gas turbines.

7)Which propelling machinery is of recent years?

It is the nuclear power plant.

8)What types of boats do you know?

I know the following types of boats: rowing boats, sailing boats, fishing boats, motorboats, life boats etc.

Unit 2. Tonnage of Ships

1)What is the displacement of a ship?

It the quantity or volume of water displaced by a ship.

It is equal to the weight of the ship.

2)How can the displacement of a ship be expressed?

It may be expressed either in cubic feet or in tons.

3)What kinds of tonnage do you know, and how they are applied?

I know deadweight tonnage, gross register tonnage and register tonnage. The deadweight tonnage is used for cargo ships and the gross and net register tonnage are used for passenger ships.

4)What spaces are deducted from the gross register tonnage to obtain the net register tonnage?

From the gross register tonnage are deducted such spaces, as may have no earning capacity, such as: machinery spaces, engine rooms, officers and crew’s quarters, alley spaces, spaces used in steering, etc.

Unit 3. Dimensions of a Ship

1) Which length is called the designer’s length and what is its abbreviation?

The designer’s length is the length between perpendiculars. Its abbreviation is Lpp.

2) What do you call the length from the extreme point of the stem to the extreme point of the stern?

It is the length over all.

3)What measurements are used for the breadth of the ship?

There are two measurements:

a) Breadth moulded which is the breadth of the ship at its widest point measured to the outside surface of the frames.

b)Breadth extreme which is the breadth measured to the outside surface of fenders or plating.

4)Which distance is called the depth of the ship?

It is the vertical distance from the keel at the centreline to the top of the deck beams of the highest complete watertight deck measured at the side.

5)What do you call the vertical distance from the water to the weather deck edge?

It the freeboard.

6)What is the draught of a ship?

It is the vertical distance from the surface of the water to the bottom of the ship.

7)What do you call the draught measured

a) at or near the stem?

b)At or near the sternpost?

a) The draught measured at or near the stem is called the draught forward.

b)The draught measured at or near the sternpost is called the draught aft.

8)Give a definition of the mean draught.

The mean draught is the mean value of the draught forward and aft.

9)What do you call a ship designed to have the same forward and aft?

It is an even keel ship.

10)Explain the statement: The ship is out of trim.

The hip is said to be out of trim when the draught forward and draught aft are not equal.

11)Where do we indicate the maximum draught to which merchant ships may be loaded?

It is indicated on the side of the ship at the midship section.

12)What is the name of the mark which indicates the maximum draught?

Its name is the Plimsoll mark.

Unit 4. Strength of Ships

1) When is a ship’s structure said to be sufficiently strong?

It is said to be sufficiently strong if it can support all the fixed loads of its machinery, fittings and equipment and all the cargo loads, and if it can withstand all the hydrostatic and hydrodynamic loads which can be imposed upon it.

2) When is a ship’s structure said to be sufficiently stiff?

It is said to be sufficiently stiff if, under any of the service loads, it does not flex or deform unduly.

3) To what kind of loads is a ship hull subjected?

It is subjected to vertical and lateral bending and twisting all at the same time.

4) Why is it so important that the structural material be well disposed and proportioned?

It is so important because the following requirements in building a ship must be satisfied:

– the ship hull must have minimum weight;

– the ship must be built at minimum cost, and

– the ship must perform all its functions acceptably.

Unit 5. Stability

1) What kinds of stability has a ship?

A ship has two kinds of stability, longitudinal and transverse.

2) Which of them is more important?

The transverse stability is more important than the longitudinal stability.

3) What is the tendency of the longitudinal and what of the transverse stability?

The longitudinal stability tends to keep a ship from rolling end over end. The transverse stability tends to keep the ship from capsizing.

4) What is the name of the force that keeps the ship on an even keel?

Its name is the force of buoyancy.

5) To what is the sum of the vertical components of the hydrostatic pressure equal?

The sum of the vertical components of the hydrostatic pressure is equal to the weight of the water displaced by the underwater body.

6) What force keeps the ship afloat?

The force of buoyancy keeps the ship afloat.

7) In which cases is the force of buoyancy reduced?

It is reduced if too much weight is introduced into the underwater body or on one side of the centerline as well as if the ship is stranded and the force of buoyancy is reduced by the reduction of the hydrostatic pressure acting on the underwater body.

8) Give the names of the static forces acting upon the ship hull.

They are the force of buoyancy and the weights on the ship.

9) Give the names of the dynamic forces acting upon the ship hull.

They are the force of wind and waves.

10) The characteristics of a force are its magnitude, line of action and sense. Which of these factors makes the force a vector quantity? Give some examples of scalar quantities.

A force is a vector quantity because besides its magnitude it has a line of action and a sense. Scalar quantities are: mass, time, numbers, etc.

11) What is the center of gravity of a ship?

The center of gravity of a ship is the point where the sum of the moments of all the weights of the ship with reference to any axis through this point is equal to zero.

12) In what plane does the center of gravity lie?

It lies in the longitudinal vertical centerline plane.

13) Where does the center of pressure of the force of buoyancy lie?

It lies at the center of gravity of the volume of displacement.

14) Suppose that the ship is on an even keel, i.e. the centerline plane is perpendicular to the surface of the water. In which plane does the center of buoyancy lie in that case?

It lies in the vertical longitudinal centerline plane.

15) Does the center of buoyancy remain in the same plane when the ship lists or rolls?

No, it doesn't.

16) How is the angle of inclination of a ship designated?

It is designated by the Greek letter phi.

17) How is the point M, the metacenter of the ship, obtained when the ship is inclined?

It is obtained by drawing a vertical line from B1 which cuts the vertical plane of the centerline.

18. Which distance is the metacentric height of the ship?

It is the distance between the center of gravity and the metacenter of the ship.

Unit 6. Building Systems and Their Characteristics

1) To what kind of forces is a ship hull subjected?

It is subjected to the different kinds of static and dynamic forces.

2)In what direction do these forces act upon the ship hull?

They act transversely, longitudinally and torsionally.

3)What are the basic structural members that provide the transverse strength of the ship?

They are ordinary frames, web frames or side transverses; beams, web beams or deck transverses; and floors or bottom transverses.

4. What are the basic structural members that ensure the longitudinal strength of the ship?

They are the keel plate, the centre girder, side girders, the sheer strake, the deck stringer plate, and that portion of the plating that is at the farthest distance from the neutral axis.

5)Explain the table which shows the characteristic features of the three kinds of building systems?

The table shows the characteristic feature of the three kinds of building systems. When the ship is built according to the transverse system, the side plating is stiffened by the transverse frames, the deck plating by the beams, and the bottom plating by the floors which may be plate floors or watertight floors. If the longitudinal system of building is applied the side, deck and bottom plating are stiffened by the side, deck and bottom longitudinals. In case of the combination system of building the bottom and deck plating are stiffened by the bottom and deck longitudinals while the side plating is stiffened by the transverse frames which may be ordinary or web frames.

6)What system of building is generally used for the fore and after peak?

A special transverse system is used for the peaks.

7) What is the characteristic form of the peaks?

At the peaks the hull form is abruptly changed because the ship breadth is suddenly reduced.

БИБЛИОГРАФИЧЕСКИЙ СПИСОК

1.Грамматика английского языка: Пособие для студентов педагогических институтов и университетов / В.Л Каушанская, Р.Л. Ковнер, О.Н. Кожевникова , Е.В.Прокофьева. - М.: «Страт», 2000. – 319 с.

2. Снежко Н.А. Английский язык для судовых механиков: учебное пособие / Н.А.Снежко, А.Д.Шерешевская, В.М.Ласточкин. - М.: Мортехинформ-реклама, 1989. – 200 с.

3. Shipbuilding 1989-1998

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