General Hydrocarbon gas normally encountered in petroleum tankers cannot burn in an atmosphere containing less than approximately 11% oxygen by volume. One way to provide protection against fire or explosion in the vapour space of cargo tanks is to keep the oxygen level below that figure. This is usually achieved by using a fixed piping arrangement to blow inert gas into each cargo tank in order to reduce the air content, and oxygen content and render the tank atmosphere non-flammable. Sources of Inert Gas Possible sources of IG on tankers and combination carriers are:Uptake gas from … [Read more...]
Archives for September 2016
Longitudinal Stability for Ships
Any Ship when at rest in calm water, the COB and the COG will be in a vertical line.Pitch Pitch is caused when a wave changes the underwater volume of a ship, making the forces of gravity and buoyancy to get separated by a distance and forming a couple which leads to dip or uplift in the bow or the stern of vessel. The up and down movement of the ship's ends, due to longitudinal shift of COB resulting from wave action, is called pitch.If a wave cause an increase in the underwater volume aft, and a decrease fwd, the COB will shift aft. The forces of gravity and buoyancy will now get … [Read more...]
Man Overboard – Manoeuvers you need to know to save a life
From the very time a man falls over, till he is recovered back on board, every second counts. Every wrong action taken or an inappropriate decision you make, the results can be catastrophic, so as a prudent navigator it’s more than necessary to know the steps to be taken when this godforsaken Man overboard emergency arrives. Three scenarios:Immediate action: The person overboard is noticed from the bridge and action is taken immediately Delayed action: The person is reported to the bridge by an eye witness and action is initiated with some delay. Person missing action: The … [Read more...]
Ship’s you need to sail on before you die!
Well if your reading this there is a fair chance that you possess the essential document to venture out into the blue, the Continuous Discharge Certificate (CDC) commonly known as the Seaman book—your license to work, your identification as a sea dog and a prerequisite for your bread and butter.We are sucked into this pipeline as cadets and trainees and pumped out as Captains or Chief Engineers (mostly) but during this entire quest at sea what holds with you thick and thin is your Seaman book. So to add another feather to the cap, why not glorify this paper of a booklet with some … [Read more...]
What is ALARP and why do you need to know it?
ALARP stands for "as low as reasonably practicable", and is a term often used in health and safety to represent that adequate consideration shall be taken in regard to risk, risk control and risk reduction. The core is the concept of "reasonably practicable"; this involves weighing a risk against the trouble, time and money needed to control it. Thus, ALARP describes the level to which you would expect to see workplace risk controlled. ALARP is not prescriptive and consequently can be challenging because it requires employers to exercise judgement. It is therefore for employers to ensure … [Read more...]