43 nations have over 600 submarines

At present, 43 nations have over 600 submarines

TNN | Aug 19, 2013, 06.03 AM IST

The INS Sindhurakshak tragedy has brought the focus on the mysterious world of submarines. Here are some interesting submarine facts.

When was submarine first used in war?

By early 18th century, many inventors made several designs of naval vessels that could travel on the surface as well as beneath water. The American Revolution was the first war that witnessed military deployment of such boats. Submarines were also used during the American civil war. Submarines equipped with torpedo became a major factor during the First and the Second World War. According to US navy at present there are 43 countries operating over 600 submarines.

How does a submarine submerge?

One of the most important features of a submarine’s design is the ballast tanks. These tanks could be alternatively filled with water or air depending on the requirement, whether the vessel wants to float on water’s surface or travel underwater. The tanks are filled with air when the submarine is at the surface. To submerge the air is released and the tanks are filled with sea water which makes the vessel heavier.

Submarines maintain a stock compressed air while travelling underwater. This air is used for life support and for filling the ballast tank.

How does a submarine propel?

Most of the today’s diesel submarines work like a hybrid vehicle. A typical diesel submarine has two diesel engines. One engine is used to propel the vehicle when it is on surface while the other is used to charge its batteries. These vehicles can only go underwater after fully charging their batteries. After going underwater they are propelled by battery-powered electric motors. Because of the battery powered propulsion the diesel submarine can stay underwater for a limited period.

A nuclear powered submarine is not based on combustion engine. Unlike diesel subs, a nuclear sub doesn’t need air to burn it fuel and hence it can remain underwater for a much longer period.

How is the underwater navigation done?

Typically, submarines don’t have windows and hence the crew could see outside underwater. When a submarine is near surface then it uses periscope to have the outside vision. Most of the submarine travel much deeper than the periscope depth and the navigation is done with the help of computers. Like any other conventional ship, a submarine navigator is also dependent on regular ocean navigation chart.

The submarine uses Sonar (Sound Navigation and Ranging) to detect target ships.

How is the submarine’s environment controlled to support life?

Modern submarines- nuclear as well as diesel are designed to stay underwater for a significantly longer period. To have a healthy environment for humans a submarine is required to maintain earth like air quality, supply fresh water and maintain suitable temperature. Most of the submarines are equipped with oxygen generator and water purifiers.

These equipments use sea water to generate oxygen as well as produce fresh water. Apart from this the carbon dioxide and moisture is periodically removed to keep the environment healthy.

http://timesofindia.indiatimes.com/india/At-present-43-nations-have-over-600-submarines/articleshow/21907516.cms

“Even a 400-metre ship in a typhoon is at the mercy of the elements.”

She’s a big ‘un all right.

The biggest ship in the world

The Maersk ‘Triple-E’ container ship is the biggest vessel in the world. But what goes into building the ultimate engine of commerce?

Big, they say, is beautiful. Whether you apply that principle to cargo ships depends how much you like winches, grease stains and enormous, smoke-belching funnels. But, beautiful or not, the Maersk Mc-Kinney Møller is a landmark in engineering.

A quarter-of-a-mile long, 195ft wide — equivalent to an eight-lane motorway — and 240ft high, the vessel, which began its maiden voyage earlier this month, is the biggest ship in the world.

Its sole purpose is to plough the trade route between Asia and Europe, bringing us millions of products manufactured in China, Malaysia and Korea, before returning, rather lighter, with exports from the West.

No ship has ever been able to carry so many goods in one journey; the Mc-Kinney Møller has room for 18,000 containers, each of them 20ft long, 8ft wide and 8ft high. That’s enough space for 36,000 cars or 111 million pairs of trainers. But Maersk, the ship’s Danish owner, will not just benefit from the economies of scale that spring from operating such a large vessel; it will also save money on petrol.

The ship has been designed to sail at an average of only 16 knots – a system known as “super slow steaming” – which is expected to save the company around £750,000 in fuel on a typical journey between Shanghai and Rotterdam.

It will still emit egregious amounts of pollution – cargo ships use a form of high-sulphur fuel, banned on land, that has been linked to cancer, heart disease and coastal erosion.

But, instead of burning 214 tons a day, the Mc-Kinney Møller will burn a slightly less-damaging 150 tons, which Maersk executives insist is a step in the right direction. The slow speed also reduces carbon dioxide emissions.

Over the next two years, Maersk is overseeing the construction of another 19 similar vessels, forming a class of ship it calls “Triple-E” dedicated to the Asia-Europe route.

The captain of the third Triple-E will be David Johnstone, from Wishaw, in Lanarkshire, a Harley-Davidson fanatic who has been skippering container ships for 24 years.

On the day I spoke to him he had just returned from Belfast where he’d visited an exhibition about another big ship – the Titanic.

Was that necessarily the best preparation for his new job?

Johnstone insisted it was. “The Titanic has fascinated me for 40-odd years. I’ve got books on the Titanic, I’ve got a 3ft print of the Titanic on my wall. I went to the exhibition with 40 other bikers and they thought it was hilarious to get me to pose in the souvenir shop with a captain’s hat.

“But, when it came to the exhibition itself, I went round on my own. The story reminds you that no ship is impregnable. Even a 400-metre ship in a typhoon is at the mercy of the elements.”

http://www.telegraph.co.uk/finance/newsbysector/industry/10203784/The-biggest-ship-in-the-world.html

The loss of HMS Thetis in 1939