Sonar

Sonar or Sound Navigation Ranging is a technology which involves the use of sound to detect vessels and other objects underwater or on the surface to aid navigation and avoid collisions. Sonar are of two types: active sonar and passive sonar. Active sonar emits pulses of sounds and listen to echoes from other vessels or…

Stern Tubes

The stern tube is a hollow tube located at the lower stern part of the ship carrying the tail shaft and connecting it to the propeller,bearing for the tail shaft, lubrication arrangement and sealing arrangement. The propeller shaft or tail shaft is supported in a stern tube bearing. The bearing being at the end of…

Deep Submergence Rescue Vehicles

A Deep Submergence Rescue Vehicle or DSRV is a marine vessel used for rescuing crew from downed submarines and other clandestine missions. These are specialized vessels that require highly skilled professionals to operate these vessels and successfully carry out complex rescue missions. There are a number of countries that operate DSRVs with different designations for…

Propeller and Rudder.

A propeller is a device with a rotating hub and radiating blades made of bronze and brass. It transforms rotary power into linear thrust by acting on a working fluid like water or air thus moving a ship forward. The rotational motion of the blades is converted to thrust by creating a pressure difference between…

Purifiers and Clarifiers.

These are two centrifuges used onboard ships to separate two liquids with different densities from one another in the case of purifiers or to separate impurities from water in the case of clarifiers. Operations. They contain discs stacked up together numbering 150, separated from each other by a very small gap. A series of holes…

Freshwater Generator.

It is an auxiliary machinery used in ships to produce freshwater from seawater. The freshwater produced is used for domestic purposes such as cooking, drinking, heating, washing and for cooling of machinery parts. The major components of a freshwater generator are; vapour condenser, Demister, Evaporator,Orifice, Seawater pump,Brine ejector,Air ejector, Salinometer, Distillate pump,Swing valve. How the…

Hydrogen powered ships.

Hydrogen powered ships are ships that are powered by electric motors supplied with electricity from a fuel cell, or use hydrogen as fuel in an internal combustion engine. While these vessels are not widely used, this technology has been demonstrated to be viable. There are several vessels with varying levels of hydrogen refuelling capability. Some…

Hydrogen Fuel Cells.

A fuel cell is a device that converts stored chemical energy into electrical energy. Hydrogen fuel cells utilize hydrogen gas and oxygen gas as fuel. The products of the reaction are water, electricity and heat. This is a stark contrast to internal combustion engines, coal fired power plants and nuclear power plants which all produce…

Four stroke engines.

Four stroke engines are internal combustion engines that require four strokes of the piston to complete one cycle of operation. Strokes refer to the movement of the piston in upward and downward direction. The cycle of operation of the engine are; intake, compression, combustion, exhaust. Intake: During this stage, air is sucked into the cylinder…

Two Stroke Engines.

Two stroke engines are engines that require two strokes of the piston to complete one cycle of operation. In other words, the entire cycle of the engine operation which involves intake, compression, ignition and exhaust take place due to the movement of the piston in two strokes,(ie upward and downward movement of the piston in…