The sextant is an instrument used to measure angles. Its arc is one sixth of a circle. Hence it is called a sextant.In actual practice, the arc of the sextant is about 60°. Being an instrument of double reflection, it can measure angles up to
A change in draught may arise during a voyage due to factors such as cargo and ballast changes as well as sea water density, and dynamic factors such as squat, pitch /roll etc. These factors should be considered in the appraisal and appropriate figures calculated
Below is the list of mandatory alarms / indication as per MSC Resolution 232(82). Alarm: An alarm or alarm system which announces by audible means, or audible and visual means, a condition requiring attention. Indicator: Visual indication giving information about the condition of a system
ENCs are updated by weekly ‘Notices to Mariners’ issued by Hydrographic Offices / Regional ENC co-ordination centers ( RENC) and corrections are received on the vessel either by email or data file (AVCS DVD). The actual updating is either applied to the ECDIS chart database
A valuable function of ECDIS is to continuously display position fixes and at the same time, monitor a detection area ahead of the ship for hazards to navigation. This detection area may have a different name depending on the manufacturer, but common terms include‘safety frame’
Finding the Quadrant – Northern Hemisphere Northern Hemisphere If the wind veers she is in the right hand semicircle (Dangerous Semicircle)If the wind backs she is in the left hand semicircle (Navigable semicircle) Navigable Semicircle Northern HemisphereProceed at maximum practical speed, alter courses as wind
Purpose of steering gear The steering gear provides a movement of the rudder in response to a signal from the bridge to steer the ship. Accidents because of steering gear failure are common in the maritime industry. Such incidents have led to some serious accidents
How CO2 extinguishes fire At atmospheric pressure carbon dioxide is a colouless, odourless and non-conductive gas that can quickly and thoroughly permeate a protected area, reduce the oxygen to a level below 15%, where combustion is not supported and extinct the fire. CO2 extinguishes the
Three types of methodsVessel generally use any one of the following methods: “Dropping” or “letting go” anchor from the hawse pipe of just above the water line. For depths up to 20m. “Walking back” anchor just above the sea bed for depths between 20 to
Weather routeing is the procedure of ensuring that the ship makes an ocean passage in the least possible time conducive to the safety of the vessel. In order to do effective weather routeing the following steps must be considered⦁ Ships performance curves must be drawn⦁