Marine Engineering

Ozone depleting substances are man-made gases that destroy ozone once the gases reach the ozone layer. The ozone layer sits in the upper atmosphere and reduces the amount of harmful ultra violet radiation that reaches Earth from the sun.  Ultraviolet radiation can have detrimental effects on both humans and the environment such as inducing skin cancer and cataracts, distorting plant growth and damaging the marine environment . Ozone depleting substances include: chlorofluorocarbons (CFCs) hydrochlorofluorocarbons (HCFCs) hydrobromoflurocarbons (HBFCs) halons methyl bromide carbon tetrachloride methyl chloroform They have been used as: refrigerants in commercial, home and vehicle air conditioners and refrigerators foam blowing agents a component in electrical equipment industrial solvents solvents for cleaning (including dry cleaning) aerosol spray propellants fumigants.  According to MARPOL annex 6, requirement for control of emission from ships ...

Nitrogen oxides are the major air pollutants and pose a challenge to engine manufacturers to meet the limits set forth by the MARPOL Annex VI.  Combustion of fuels is the primary anthropogenic source of formation of nitrogen oxides, While Nitric oxide (NO) and nitrogendi-oxide are usually grouped together as NOx emissions, nitric oxide is the predominant oxide of nitrogen produced by combustion process. Therefore, it is an important minor species in the combustion because of its contribution to air pollution.  The principal source of NO is the oxidation of atmospheric (molecular) nitrogen. However, if the fuel contains  significant  nitrogen, the oxidation of the fuel nitrogen-containing compounds  is an additional source.  In the combustion of fuel that contains  no nitrogen , nitric oxide is formed by  three chemical mechanisms  that involve nitrogen from the air.  The  three principal mechanisms are: i) The th...

Watertight Door Weather tight  Door A watertight door prevents the passage of water when exposed to head of water. A typical head of water for a ship could range from 3-10 meters(tested up to 20 meters resistance) A weather tight door is designed to be located on the deck of the ship above the waterline, where they can be subject to the adverse weather conditions experienced offshore. Watertight doors are tested using a pressure tank where a hydrostatic pressure can be applied to the door. Weather tight doors are also designed to withstand brief submersion experience from green seas. This means a weather tight door can withstand a small head of water(generally no higher than the height of the door) The door is generally pressurized form the inside as this is worst case scenario. A weather tight door is generally tested with a high pressure hose, which is directed at the seal.