Fig.9. A capstan on a sailing ship.

 

The word, connected with the Old French capestan or cabestan(t), from Latin capistrum, -a halter, from capere, to take hold of, seems to have come into English (14th century) from French or Spanish shipmen at the time of the Crusades.

A capstan is a rotating machine used to apply force to another element, notably used on board ship and on dock walls, for heaving-in or veering ropes, cables, and hawsers.

In its earliest form, the capstan consisted of a timber mounted vertically through a vessel's structure which was free to rotate. Levers, known as bars, were inserted through holes at the top of the timber and used to turn the capstan. A rope wrapped several turns around the drum was thus hauled upon. A rudimentary ratchet was provided to hold the tension. The ropes were always wound in a clockwise direction.

Capstans evolved to consist of a wooden drum or barrel mounted on an iron axle. Two barrels on a common axle were used frequently to allow men on two decks to apply force to the bars. Later capstans were made entirely of iron, with gearing in the head providing a mechanical advantage when the bars were pushed counterclockwise.

Modern capstans are powered electrically, hydraulically, pneumatically, or via an internal combustion engine.

III. Answer the following questions:

1. What is capstan?

2. What did the capstan, in its early form, consist of?

3. Where were bars inserted?

4. Was a rudimentary ratchet provided to hold the tension?

5. Capstans evolved to consist of a wooden drum or barrel mounted on an iron axle, didn’t they?

6. How are modern capstans powered?

7. What is the origin of the word “capstan”?

IV. Translate the text “Gypsies and Wildcats.”

The wheels on either a vertical or horizontal windlass provide for either chain or line to be engaged. The wheel for line is termed a warping head, while the chain handling wheel is variously referred to as the gypsy(in the UK) or wildcat (in America), though due to the influence of the offshore oil industry the latter usage is now more common. For clarity in communication the generic term chainwheel is often used. On small craft a warping drum is sometimes used to handle both chain & rope, although particular care must be taken with sizing and compatibility of line, chain, and windlass, for this feature to work effectively.

It is important that the Chainwheel match the chain size (i.e. the link pitch) closely. Even a small difference in link size or consistency can cause undue wear on the chainwheel and/or cause the chain to jump off the windlass when the winch is operating, particularly during payout, a runaway condition sometimes referred to as "water spouting" should it occur at high speed.

Nowadays, especially on large tankers and cruise ships, the windlass may be split into independent Port & Starboard units. In these cases they are frequently coupled with Warping Drums. In some of these the warping drums are of the self tensioning or constant tension type.

V. Insert the missing words in following sentences:

1. A capstan is a … machine used to apply … to another element, notably used on … ship and dock walls.

2. …, known as bars, were inserted through holes at the top of the … and used to turn the ….

3. The ropes were always wound in a … ….

4. Capstans evolved to consist of a … … or barrel mounted on an iron axle.

5. Modern capstans are powered …, …, pneumatically, or via an internal … engine.

VI. Ask as many questions as possible to the following sentences:

1. A capstan differs from a windlass in having the axis on which the rope is wound vertical instead of horizontal.

2. Vertical capstans use a vertical shaft with the motor and gearbox situated below the winch unit.

3. Vertical capstans allow the machinery to be placed below decks, thus lowering the center of gravity.

4. The term “winch” generally implies a machine which stores the rope on a drum.

5. Typically, a gearbox is used which trades reduced speed, relative to the prime mover.

VII. Use the following words and word combinations in sentences of your own:

   To apply force, veering ropes, a vessel’s structure, to rotate, to insert through holes, to turn the capstan, to wind in a clockwise direction, to consist of a wooden drum, to push counterclockwise, to be powered hydraulically.

VIII. Translate the text “A jackline”

A jackline is a rope or wire strung from a ship's bow to stern to which a safety harness can be clipped, allowing a crewmember to move about the deck safely when there is risk of falling or being swept overboard. They are usually attached to strong padeye or cleat fittings at both ends of the boat, allowing the crewmember to move fore and aft by sliding their harness' clip along the line. Jacklines may be made of wire or low-stretch rope. More recently, sailors are using high strength nylon webbing. The reason is that flat webbing does not roll under foot while working on deck. This reduces the hazard that can be created by using rope. The image to the right shows the traditional steel wire jackline and the image below shows an example of a more modern jackline made of flat nylon webbing.

IX. Retell the text “Capstan”

 

UNIT 11. WINCH

I. Words and word combinations to be remembered:

a winch – лебедка

to wind up – наматывать

to wind out – разматывать

wire cable – стальной трос

a spool – катушка, бабина

tow trucks – эвакуатор

an internal combustion drive – привод внутреннего сгорания

a solenoid brake – соленоидный тормоз

ratchet and pawl device – храповой механизм

halyard – фал

a stripper – стриппер

II. Read and translate the following text:

A winch is a mechanical device that is used to pull in (wind up) or let out (wind out) or otherwise adjust the "tension" of a rope or wire rope (also called "cable" or "wire cable"). In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and elevators. The spool can also be called the winch drum. More elaborate designs have gear assemblies and can be powered by electric, hydraulic, pneumatic or internal combustion drives. Some may include a solenoid brake and/or a mechanical brake or ratchet and pawl device that prevents it from unwinding unless the pawl is retracted.

Fig.10. Anchor winch

The rope is usually stored on the winch, but a similar machine that does not store the rope is called a capstan. When trimming a line on a sailboat, the crew member turns the winch handle with one hand, while tailing (pulling on the loose tail end) with the other to maintain tension on the turns. Some winches have a "stripper" or cleat to maintain tension. These are known as "self-tailing" winches.

The earliest literary reference to a winch can be found in the account of Herodotus of Halicarnassus on the Persian Wars, where he describes how wooden winches were used to tighten the cables for a pontoon bridge across the Hellespont in 480 B.C.

The largest electric drive winch in the world is placed on the Balder, a construction ship. It is used as a Mooring Line Deployment Winch with a diameter of 10.5 meter.

 

III. Answer the following questions:

1. What is a winch?

2. What does a winch consist of?

3. How can the spool be called?

4. How can elaborate designs be powered?

5. What do some winches include?

6. Can you describe the mechanism of trimming?

7. When can the earliest literary reference of a winch be found?

8. The largest electric drive winch in the world is placed on the Balder, isn’t it?