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For urgent orders requiring rapid acceleration, the handle is moved three times so that the engine room bell is rung three times. This is called a "cavitate bell" because the rapid acceleration of the ship's propeller will cause the water around it to cavitate, causing a lot of noise and wear on the propellers. Such noise is undesirable during ...
A circle of death can be initiated if the boat operator releases the steering mechanism while the boat is still powered, which means the propeller is still turning. The force of the rotating propeller blades incurs a force known as steering torque , causing the motor itself, which is mounted on a swivel jointed mechanism, to turn sharply into ...
The problem with diesels is that, for a given size, there is a fixed amount of power generated per cylinder. To increase power it is necessary to add cylinders but, when cylinders are added, the crankshaft has to be lengthened and after a very limited number of additions, the lengthened crankshaft begins to flex and vibrate all on its own.
This solution focuses on the materials that marine propellers are created from which is a direct factor in cavitation. While redesigning propellers would only garner an extra one or two percent efficiency in operation, changing the materials a propeller is made from has greater effects. [ 3 ]
According to sensory conflict theory, the cause of terrestrial motion sickness is the opposite of the cause of space motion sickness. The former occurs when one perceives visually that one's surroundings are relatively immobile while the vestibular system reports that one's body is in motion relative to its surroundings. [ 12 ]
The amplifying devices in audio and radio equipment are vulnerable to a variety of feedback problems, which can cause distinctive noise in the output. The term motorboating is applied to oscillations whose frequency is below the range of hearing, from 1 to 10 hertz , [ 3 ] so the individual oscillations are heard as pulses.
The result was Practical Boat Handling, the first edition of which was published in 1917 with 144 pages, 5 × 7 in.. From this, the book evolved through many editions into Piloting, Seamanship & Small Boat Handling. The book title has now been shortened to Chapman Piloting & Seamanship.
When a boat is running with the wind coming directly from astern and the mainsail and jib are on opposite sides of the vessel, the windward side is considered to be that opposite to the site on which the mainsail is being carried. On a starboard tack the mainsail is on the port side; on a port tack the mainsail is on the starboard side. [3]