The Hellenic Navy (HN) (Greek: Πολεμικό Ναυτικό, Polemikó Naftikó, abbreviated ΠΝ) is the naval force of Greece, part of the Greek Armed Forces. The modern Greek navy has its roots in the naval forces of various Aegean Islands, which fought in the Greek War of Independence. During the periods of monarchy (1833–1924 and 1936–1973) it was known as the Royal Navy (Βασιλικόν Ναυτικόν, Vasilikón Naftikón, abbreviated ΒΝ).The total displacement of all the navy's vessels is approximately 150,000 tons.The motto of the Hellenic Navy is "Μέγα το της Θαλάσσης Κράτος" from Thucydides' account of Pericles' oration on the eve of the Peloponnesian War. This has been roughly translated as "Great is the country that controls the sea". The Hellenic Navy's emblem consists of an anchor in front of a crossed Christian cross and trident, with the cross symbolizing Greek Orthodoxy, and the trident symbolizing Poseidon, the god of the sea in Greek mythology. Pericles' words are written across the top of the emblem. "The navy, as it represents a necessary weapon for Greece, should only be created for war and aim to victory."...............The Hellenic Merchant Marine refers to the Merchant Marine of Greece, engaged in commerce and transportation of goods and services universally. It consists of the merchant vessels owned by Greek civilians, flying either the Greek flag or a flag of convenience. Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and a key element of Greek economic activity since the ancient times. Nowadays, Greece has the largest merchant fleet in the world, which is the second largest contributor to the national economy after tourism and forms the backbone of world shipping. The Greek fleet flies a variety of flags, however some Greek shipowners gradually return to Greece following the changes to the legislative framework governing their operations and the improvement of infrastructure.Blogger Tips and Tricks
This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς....This is a bilingual blog in English and / or Greek and you can translate any post to any language by pressing on the appropriate flag....Note that there is provided below a scrolling text with the 30 recent posts...Αυτό είναι ένα δίγλωσσο blog στα Αγγλικά η/και στα Ελληνικά και μπορείτε να μεταφράσετε οποιοδήποτε ποστ σε οποιαδήποτε γλώσσα κάνοντας κλικ στη σχετική σημαία. Σημειωτέον ότι παρακάτω παρέχεται και ένα κινούμενο κείμενο με τα 30 πρόσφατα ποστς.........

Tuesday, July 29, 2014

Lightning hits the sea ..[ 4389 ]

Who, what, why: What happens when lightning hits the sea?

BBC || 28 July 2014 Last updated at 16:44 GMT 

Magazine Monitor
Storm at sea, near site of Costa Concordia sinking
Who, What, Why The Magazine answers the questions behind the news
A man died and several other people were injured in a thunderstorm off the coast of California. What happens when lightning hits the sea, asks Justin Parkinson.
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If you are in the sea and a thunderstorm looks likely in the area, there are two ways to cut the risk of getting hit - get out and find some shelter, or swim deeper.
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A typical lightning flash measures about 300 million volts and 30,000 amps, according to the US National Weather Service - enough to kill.
Most of the electrical discharge spreads horizontally rather than vertically. This is bad news for people, who tend to float or swim on or near the surface.

The answer

  • Lightning largely spreads along the surface
  • Fish, swimming beneath the surface, are less likely to be hurt than humans
The lightning current is likely to radiate across the surface. Various different estimates have been given for the distance over which it would dissipate to the point where it would not be a harmful to a person.
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"I wouldn't recommend betting your life on that kind of calculation," says Giles Sparrow, author of Physics in Minutes. "If you get out of the water and can't find shelter, it's best to crouch into a ball, rather than lay flat on the floor, as this also raises risks.
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 If you stay in the water, you could try to go deep, but it's unlikely you can hold your breath for long enough to avoid the danger."
Fish, which usually move around at greater depths, are safer than human swimmers. Protruding heads or even entire bodies, such as those presented by surfers or paddle boarders, could put people in greater danger.
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"If you are in the open sea, rather like standing in an open field, you might become a target during a storm," says Jon Shonk, a meteorologist at the University of Reading. "Lightning takes the path of least resistance."
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Boats can be fitted with lightning conductors, which direct the charge into the sea, while avoiding their most vulnerable parts, such as passenger areas or equipment rooms. It is recommended that these are fitted.
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Research by Nasa shows lightning is more likely to hit land than sea and that it is rare for strikes to occur in deep ocean areas. Waters just off coasts are more often affected.
Risks also vary according to seasons. "You expect more strikes nearer to land because that's where the most heat and updrafts and storms build up, especially in the summer," says Shonk. "That can change in winter, but that's obviously a time when there are fewer people in the sea."
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