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Noise generated on board ships and submarines can have far-reaching effects on the ability of the vessel to operate safely and efficiently. Military vessels in particular need to be quiet to avoid detection by sonar , so many methods have been used to limit a vessel's noise signature.
The pivoting design allows the outboard motor to be swiveled by the operator in almost all directions: Sideways for direction, up and down to change the thrust line according to speed or bow lift, elevate completely out of water for easy starting, placing the drive shaft and the propeller forward along the side of the boat for reverse, or put ...
A chatter mark is an irregular surface flaw left by a wheel that is out of true (off-center) in grinding, [1] or regular marks left when turning a long piece on a lathe, due to machining vibrations. As early as 1907, Frederick W. Taylor described machining vibrations as the most obscure and delicate of all the problems facing the machinist , an ...
Marine propulsion is the mechanism or system used to generate thrust to move a watercraft through water. While paddles and sails are still used on some smaller boats, most modern ships are propelled by mechanical systems consisting of an electric motor or internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller.
Brightwork also known historically as "bright work" refers to the exposed and varnished wood or metal work of a boat. [1] The metal is usually brass or bronze that is kept polished, or stainless steel, which requires less maintenance. [2] In the past, due to the environmental exposure experienced by boats, corrosion and UV damage made ...
Electrofishing by boat. There are three types of electrofishers: backpack models, tote barge models, and boat mounted models, sometimes called a stunboat. [2] Backpack electrofisher generators are either battery or gasoline powered. They employ a transformer to pulse the current before it is delivered into the water.
Various examples of metal swarf, including a block of compressed swarf. Broken up chips are preferred over stringy drill chips. [1]Metal swarf, also known as chips or by other process-specific names (such as turnings, filings, or shavings), are pieces of metal that are the debris or waste resulting from machining or similar subtractive (material-removing) manufacturing processes.
Radiated noise is the noise generated by a ship that has an effect on other ship's sensors, especially submarines. The Masker-Prairie countermeasure systems are key elements in this program to reduce radiated noise and self-noise that are not reduced by controlling the sounds at their source or their transmission to the hull. [2]