The Engineering Diary

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Fuel Oil Testing On-board On-board testing of the fuel could be carried out during the bunker operation by one of the engineering staff not required to supervise or monitor the bunkering operation. The following tests could be carried out:   Water content   Viscosity   Density   Compatibility   Check for abrasive fines Although the tests are not as accurate as a shore based laboratory the tests would indicate whether the fuel loaded is the same as the fuel quality ordered and therefore the bunker receipt. Importance of Fuel Oil Sampling A representative sample would be obtained by a permanent sampling probe fitted close to the bunkering manifold. The rate of sampling would ensure that a sampling quantity required is taken over the full duration of the bunkering operation. The sample container is then thoroughly mixed before being poured into new, clean containers. The containers are then sealed and signed before being sent to the shore testing facility. Effects ...

In today’s world, the four main materials used for building boats, when we talk at the level of mass manufacturers, are steel, aluminium, fibre-reinforced plastic (FRP), and polyethylene. Let us speak about each of these in greater detail. Steel Steel is one of the most popular materials used for boats and has consistently been the material of choice for the past century. Its high strength, durability, resistance to abrasion, and relatively low cost are some of the main reasons why steel is widely used in the industry. However, in the wake of the development of new composite materials, better and cheaper alternatives are being used for manufacturing boats of equal size and strength but considerably lesser weight. This has reduced the importance of steel in boat building to an extent, although it is still used extensively for larger ships. From the point of view of sustainability, steel has a practically airtight production process that produces minimal constructional waste. In addition...

  Welding Methods And Weld Defects PART 20   Welding is one of the most widely used hot-work processes used in the shipbuilding industry. The development in welding technology has enabled the industry to produce perfectly watertight and oil-tight joints. Welded joints as compared to riveted joints are much easier to produce and they reduce the cycle time of the project. Welded joints have also resulted in reduced steel weight and require less to negligible maintenance compared to rivet joints. The major contribution of welding technology to the shipbuilding industry is the possibility of producing smooth hull surfaces, therefore reducing the bare hull resistance and power requirements considerably.   Welded joints as compared to riveted joints are much easier to produce and they reduce the cycle time of the project. Welded joints have also resulted in reduced steel weight and require less to negligible maintenance compared to rivet joints. The major contribution o...

Types of Ships Cargo ships are classified into various types on the basis of purpose, size, type of cargo etc. The economic factor is of prime importance in designing a merchant ship. Every owner wants maximum return on their investment which means a ships construction not only depends on the current economic necessities but the factor of future adaptability also plays a part. From the preliminary design of a vessel due for construction, the following information can be obtained: 1.      Dimensions 2.      Displacement 3.      Stability 4.      Propulsive characteristics and hull form 5.      Preliminary general arrangement 6.      Principal structural details A layout of the various ship types and their subdivisions will be listed out, covering a wide range of all vessels in operation.  The type of ship plays an important role in deciding the above mentioned parameters. Types of Ships Ships a...

Gearing and tail shafts Vessels with low speed engines typically use direct drive from the crankshaft to the tail shaft with its propeller. Smaller domestic commercial vessels typically operate with high speed engines where direct drive shafts would revolve too fast to drag water across their propellers without efficiency losses due to cavitation (bubbling in the water flow). Consequently a gearbox is used to provide reduced speed of the shaft, reverse propulsion and through a clutch mechanism, disengaged propulsion. Gears and clutch mechanisms Principles of marine gear boxes Gearing is used in drive trains (sets of intermeshed gear wheels) to alter direction, position or speed/mechanical advantage of propulsion and auxiliary equipment such as winches, pumps and steering. The gear and shaft driven directly by the motor can be called the input and the final gear and shaft it drives can be called the output. Drive train A shown below illustrates reduction and reversal of the output, driv...