Fig. 29. Modern ship rudder

A rudder is a device used to steer a ship, boat, submarine, or other conveyance that move through a fluid. A rudder operates by redirecting the fluid past the hull, thus imparting a turning or yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern or after end. Often rudders are shaped so as to minimize hydrodynamic drag. On simple watercraft, a tiller -- essentially, a stick or pole acting as a lever arm -- may be attached to the top of the rudder to allow it to be steered by a helmsman. In larger vessels, cables, pushrods and hydraulics may be used to link rudders to steering wheels.

Generally, a rudder is "part of the steering apparatus of a boat or ship that is fastened outside the hull", that is denoting all different types of oars, paddles and rudders. More specifically, the steering gear of ancient vessels can be classified into side-rudders and stern-mounted rudders, depending on their location on the ship. A third term, steering oar, can denote both types. In a Mediterranean context, side-rudders are more specifically called quarter-rudders as the later term designates more exactly the place where the rudder was mounted. Stern-mounted rudders are uniformly suspended at the back of the ship in a central position, but the term has historically been found wanting because it does not take into account that the stern rudders were attached to the ship hull in quite a different way: While the European pintle – and – gudgeon rudder was attached to the sternpost by pivoting iron fastenings, the Arabs used instead a system of lashings. Chinese stern rudders also featured tackles, but, unlike their medieval and Arab counterparts, had no sternpost to which to attach them. Roman and particularly ancient Egyptian stern rudders featured again a different method of fastening where the stock, having a single point of contact with the stern, was additionally secured to the ship body by an upright rudderpost or braced ropes.

Boat rudders may be either outboard or inboard. Outboard rudders are hung on the stern or transom. Inboard rudders are hung from a keel or skeg and are thus fully submerged beneath the hull, connected to the steering mechanism by a rudder post which comes up through the hull to deck level, often into a cockpit.

Some sailors use rudder post and mast placement to define the difference between a ketch and a yawl, similar two-masted vessels. Yawls are defined as having the mizzen mast abaft (i.e. "aft of") the rudder post; ketches are defined as having the mizzen mast forward of the rudder post.

Small boat rudders that can be steered more or less perpendicular to the hull's longitudinal axis make effective brakes when pushed "hard over." However, terms such as "hard over," "hard to starboard," etc. signify a maximum-rate turn for larger vessels.

Oars mounted on the side of ships for steering are documented from the 3rd millennium BCE in Persia and in artwork, wooden models, and even remnants of actual boats. An early example of an oar mounted on the stern is found in the Egyptian tomb of Menna (1422-1411 BC). Stern-mounted oars were also quite common in Roman river navigation as proved from relief depictions more than a millennium later.

II. Master the Active Vocabulary:

rudder – руль

to steer – править рулем

conveyance – перевозка, транспортировка

hinge – шарнир, крюк

hydrodynamic – гидродинамический

tiller – румпель

helmsman – рулевой, кормчий

pushrod – толкатель клапана

hydraulics – гидравлика

oar – весло

outboard – за бортом

inboard – внутри судна

cockpit – кубрик

III. Answer the following questions:

1. What is a rudder?

2. How does a rudder operate?

3. What are rudders used for?

4. What links rudders to steering wheels?

5. When were the first oars documented?

6. Were stern – mounted oars quite common in Roman river navigation?

7. What are outboard and inboard rudders?

IV. Ask as many questions as possible to the following questions:

1. A rudder operates by redirecting the fluid past the hull.

2. An early example of an oar mounted on the stern is found in the Egyptian tomb of Menna.

3. On Arab ships – the rudder was controlled by two lines, each attached to a crosspiece mounted on the rudder head perpendicular to the plane of the rudder blade.

4. Outboard rudders are hung on the stern.

5. Some sailors use rudder post and mast placement to define the difference between a ketch and a yawl.

6. As the size of ships and the height of the free boards increased, quarter rudders replaced by the sturdier stern – mounted rudders with pintle and gudgeon attachment.

V. Insert the missing words using the text:

1. A rudder is a … used to steer a ship, boat, submarine or other … that move through a fluid.

2. In basic form, a rudder is a … … or sheet of material attached with … to the craft’s stern.

3. In larger …, cables, pushrods and hydraulics may be used to link rudders to … ….

4. An early example of an … mounted on the stern is found in the Egyptian tomb of …

5. Outboard rudders are hung on the …

6. … are defined as having the mizzen mast forward of the rudder post.

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

To steer a ship, to move through a fluid, a flat sheet, to minimize hydrodynamic drag, to act as a lever arm, to link a rudder to a steering wheel, remnants of actual boats, beneath the hull, deck level, to define the difference between a ketch and a yawl.

VII. Read and translate the text “Chinese rudders.”

One of the world's oldest known depiction of a stern-mounted rudder can be seen on a 2 ft. long tomb pottery model of a Chinese junk dating from the 1st century CE, during the Han Dynasty (202 BC-220 AD). It was discovered in Guangzhou in an archeological excavation carried out by the Guangdong Provincial Museum and Academia Sinica of Taiwan in 1958.

Chinese rudders were not supported by pintle-and-gudgeon as in the Western tradition; rather, they were attached to the hull by means of wooden jaws or sockets, while typically larger ones were suspended from above by a rope tackle system so that they could be raised or lowered into the water. Also, many junks incorporated "fenestrated rudders" (rudders with holes in them, allowing for better control), an innovation adopted in the West in 1901 to increase the maneuverability of torpedo boats. Detailed descriptions of Chinese junks during the Middle Ages are known from various travelers to China, such as Ibn Battuta of Tangier, Morocco and Marco Polo of Venice, Italy.

VII. Retell the text: “Rudder.”

UNIT 26. STERN

I. Read and translate the following text:

The stern is the rear or aft part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter to the taffrail.

The stern area has always been the location near the steering apparatus (rudder, tiller, ship's wheel, etc), and by extension became the domain of the ship's captain and other officers. In particular, the stern was the location of the officers' quarters, and during the age of sail of the ship, with rows of windows, galleries, walkways, and elaborate decorations. This resulted in a certain amount of vulnerability, and the goal of much maneuvering in battle was to achieve the stern rake, in which a ship would pour its entire broadside into the stern.

Other features of the stern included lanterns and the ensign.

Поиск по сайту: