Germany's Howaldtswerke-Deutsche Werft shipyard is expected to hand over one of the world's most advanced submarines to Israel's navy this year for sea trials.

The ultra-quiet, hard-to-detect Dolphin class sub is the fourth boat in a planned six-pack of submarines that are reportedly capable of firing nuclear-tipped cruise missiles, giving Israel unparalleled strategic reach in the Middle East even though until now it had never been a potent sea power.

The heavily modified Israeli Dolphins are considered the most modern non-nuclear submarines in the world.

Israel's Yediot Ahronot daily reported that the Israeli navy, indisputably the most powerful maritime force in the region, will soon begin putting the second-generation submarine through its paces after it was launched in Kiel by HDW, a subsidiary of the German engineering giant ThyssenKrupp.

The 212-foot submarine is named Tannin, Hebrew for "alligator," after the Israeli navy's first S class sub which was decommissioned in 1972.

The new Tannin is to be delivered to Israel by the end of the year.

Two other super-subs are expected to follow in 2014 and 2015. These are advanced models of the original HDW-designed diesel-electric Type-209 boat, three of which were delivered to Israel in 1998-2000. Because of extensive modifications, they were designated Dolphin class vessels.

The boats, primarily based in the Mediterranean, are reported to be regularly deployed in rotation in the Arabian Sea off southern Iran.

The first batch of Dolphins, with a range of 5,000 miles and able to stay at sea for about 40 days, needed to surface frequently to recharge their batteries.

But the Jerusalem Post says the latest models are fitted with a new propulsion system that combines a conventional diesel lead-acid battery system and an air-independent power system that allows them to stay underwater for a week at a time.

This also allows for silent cruising that makes the 1,625-ton boats hard to detect. They also carry fuel cells for oxygen.

A larger fuel capacity extends the Dolphins' range to around 6,250 miles and operational endurance to 50 days.

Western military sources say that in 2002 Israel armed the first batch of Dolphins with U.S. AGM-84 Harpoon missiles built by Boeing and fitted in Israel with nuclear warheads.

These missiles, with a relatively short range of 85 miles, were fired through the subs' torpedo tubes. These tubes were converted to 650mm, or 26-inch, caliber to accommodate the missiles.

The Israelis reportedly developed a larger cruise missile with a range of 940 miles -- roughly the distance between Tel Aviv and Tehran -- and able to carry a 200-kiloton nuclear warhead.

These weapons give Israel the capability of hitting a much wider selection of strategic targets in Iran, an important factor in any sustained assault on the Islamic Republic's nuclear installations and key military bases.

So it's ironic then that, as The Jerusalem Post reported, as of 2010 the Iranian regime held a 4.5 percent stake in ThyssenKrupp, HDW's parent company.

The Post noted that with the imposition of international sanctions on Iran in 2010 because of its refusal to abandon its contentious nuclear program, ThyssenKrupp's 2011-12 corporate report noted that the executive board "ordered a review of the business activities with Iranian customers before the tighter trade restrictions came into effect to establish whether they comply with the new laws.

"In September 2010, it was decided that ThyssenKrupp will not enter into any new transactions with Iranian customers."

The Post noted that ThyssenKrupp "has refused to evict its Iranian government stockholders from its corporate ownership."

The current confrontation between the West and Iran in the Persian Gulf, with Tehran threatening to close the vital oil artery through the Strait of Hormuz at the southern end of the waterway, has brought Israel's Dolphin fleet into sharp focus.

In January, Ron Lauder, president of the World Jewish Congress, urged the expansion of Israel's Dolphin force in a New York Post op-ed article headlined "How subs could save Israel."

"Even without an atomic threat, Israel faces a dangerous new world," Lauder wrote.

"While Iran is saber rattling in the Strait of Hormuz, it has the means to launch an overwhelming barrage of conventionally armed ballistic missiles across Israel …

"That's why Israel needs to use the Mediterranean Sea and the Indian Ocean as a bastion for its diesel-powered submarines."