Air masses are large areas of air which have the same characteristics throughout. They may be warm or cold, depending upon where they originated, ie tropical or polar. They are further classified as either continental or maritime. When two different air masses meet they form a boundary which is known as a front. Most fronts…
Last year we spoke about two atmospheric pressure systems, namely the Depression and the Anti-cyclone. This year we continue with systems which are basically derivatives of the first two: High pressure ridges. They are also known as “wedges”. It is an extension of an anti-cyclone and it could extend in any direction from its parent.…
The oceanic winds experienced in the various climate zones are described in the following sub paragraphs: Doldrums. The doldrums is that part of the ocean situated in the equatorial trough of low pressure between the trade winds of the two hemispheres. This weather in this zone is characterised by calms, light variable winds alternating with…
The planetary wind circulation for the “ideal” earth which would be covered with water is shown in the following sketch:
Last year we had a look at the causes and elements of weather. This year we will be looking at the various weather systems and the weather the mariner can expect from them. We will also be covering tropical storms, the danger they pose and the action the mariner can take to avoid them. Lastly…
The towing mentioned in this section, refers to the towing of one vessel by another in an emergency and not the professional towing of a vessel by a tug/salvage vessel. All vessels usually have a dedicated towrope/wire which is specially made up for use during an emergency. Depending on the size of the vessel, this…
A fire onboard poses a very serious threat to the vessel and the crew. There is no municipal fire service to call upon and there is no escape from the consequences of the fire. For this reason it is imperative that every precaution is taken to prevent a fire from starting and that the crew…
If a ship is damaged through a collision or some other accident and is unable to contain the resultant influx of water and it is near a suitable shore, then consideration should be given to beaching the vessel in order to prevent it from sinking and to affect temporary repairs. The most suitable would be…
Collisions. When ships are about to collide, the following action should be carried out: When one ship collides with another, there is greater likelihood of loss of life and serious damage if one vessel strikes another in the midships position where the compartments are larger (ie engine room). Every attempt must be made through the…
When it seems that the ship will have to be abandoned, the following action must be taken: The lifeboats and life rafts must be prepared for launching. In remote areas where the likelihood of an early rescue is small, consideration should be given to placing more blankets and provisions in the boats/rafts. High protein foods…
