The latest and one of the most expensive weapons in the IDF’s arsenal, the Dolphin-class submarine INS Rahav, set out for Haifa from the German port of Kiel on Thursday, according to a senior naval official.

Ordered a decade ago, the Rahav will be Israel’s fifth Dolphin-class submarine, joining the INS Tanin, Tekuma, Leviathan and Dolphin at the Haifa naval base when it arrives next month.

Rahav is the Hebrew name for the Greek god of the seas, Neptune, and has been used for other naval ships in the past, but it can also mean haughtiness or arrogance in modern Hebrew.

The submarine, built by the German Howaldtswerke-Deutsche Werft shipbuilding company, was unveiled in April 2013, but required an additional year and a half of work to make it fully operational. The diesel-powered sub is over 220 feet (67 meters) long and weighs more than 2,000 tons. It will be staffed by a crew of approximately 50 sailors, the Israel Navy official said.

The vessel’s air-independent propulsion system, which operates through a fuel cell instead of using louder, oxygen-dependent sources, allows the submarine to remain underwater without surfacing for potentially weeks at a time, the source said.

“The fifth submarine greatly enhances the Israel Navy’s submarine flotilla and provides us with another state-of-the-art tool to aid and defend Israel against numerous threats,” the Navy official said, but refused to specify to what exact dangers he was referring.

Israel Navy commander Ram Rothberg salutes the incoming crew of the INS Rahav, Israel's newest submarine, before it sets off from the German port of Kiel towards Haifa, where it is set to arrive next month, on December 17, 2015. (IDF Spokesperson's Unit)

Israel Navy commander Ram Rothberg salutes the incoming crew of the INS Rahav, Israel’s newest submarine, before it sets off from the German port of Kiel towards Haifa, where it is set to arrive next month, on December 17, 2015. (IDF Spokesperson’s Unit)

The INS Rahav cost Israel a reported $2 billion (NIS 8 billion), but the Navy officer was loath to discuss its price.

“We’re not speaking about the cost,” he said.

The price tag, seen by some as exorbitant, of the Rahav was offset by a considerable discount from Berlin that is rooted in a contentious 1953 reparations agreement between Germany and Israel for the Holocaust.

The controversial agreement, which significantly boosted Israel’s economy during the early days of its independence, has brought billions of dollars of military and economic aid to Israel throughout its history and was further invoked to purchase the new line of naval vessels.

The Rahav is equipped with state-of-the-art surveillance systems to track other ships and countermeasures to allow it to avoid detection by enemy craft, as well as satellite communications capabilities and other systems for electronic warfare, the Israel Navy officer said.

Last year, the INS Tanin — crocodile, in Hebrew — arrived in Israel. The nuclear-capable submarine, similar in most ways to the new Rahav, came equipped with 10 torpedo tubes, capable of holding a variety of missiles, according to Defense News.

Israel Navy commander Ram Rothberg salutes as the INS Rahav, Israel's newest submarine, sets off from the German port of Kiel towards Haifa, where it is set to arrive next month, on December 17, 2015. (IDF Spokesperson's Unit)

Israel Navy commander Ram Rothberg salutes as the INS Rahav, Israel’s newest submarine, sets off from the German port of Kiel towards Haifa, where it is set to arrive next month, on December 17, 2015. (IDF Spokesperson’s Unit)

Submarines, unmatched in their ability to hide from enemy navies, have long been a major facet of Israel’s defense policy. “Submarines are a strategic tool in the IDF’s defense arsenal. Israel is prepared to act at any time in any place to ensure the safety of Israel’s citizens,” Netanyahu said in 2013, when the Rahav was first unveiled in Germany.

Israeli submarines are allegedly armed with cruise missiles topped with nuclear warheads, affording the tiny Jewish state “second strike” capabilities — although the government will not officially acknowledge these nuclear weapons.

Israel also purchased a sixth submarine from Germany in 2013, which is expected to be completed in a few years. It is not yet clear if it will join the current fleet or replace one of the older vessels.

“Let’s talk about that in three or four years,” the military official said.