| ASHDOD, Israel
ASHDOD, Israel Israel's huge new offshore gas resource offers its enemies an obvious target and gives its navy, long overshadowed by other branches of the Israeli armed forces, a big job that will require extra spending.
On patrol boat 836, circling two gas platforms in choppy Mediterranean waters, Captain Ilan Lavi flipped through pictures of the possible threats: boat bombs, drones, submarine vessels, rockets and missiles.
"We have to build an entire new defensive envelope," said Lavi, head of the navy's planning department who talks as knowledgeably about the financial aspects of the gas industry as he does about security. "But you can't have a defence system that costs more to build than the gas itself."
The discovery of large natural gas deposits in its offshore economic zone in 2009 came as a welcome surprise to Israel, transforming the energy security outlook of a country that used to rely heavily on imports. A burst of exploration followed, and by the end of 2013 18 new wells are expected to be drilled at a cost of $1.8 billion (1.18 billion pounds).
The government from the outset committed to helping protect the gas fields being developed by private companies.
"The gas fields are a strategic asset and Israel will defend them," Lavi yelled above the wind and the engine roar.
"They may not be too complicated to attack, but we are aware of the threats and are prepared for them."
The navy says it is under-equipped, however, to defend a maritime area larger than Israel itself.
Israel estimates there are about 950 billion cubic metres of gas beneath its waters, enough to leave plenty for exports. A successful attack could threaten export revenues and harm domestic energy supply.
A suitable defence system will cost $700 million to build and $100 million annually to maintain, Lavi said. That is a tough sell in a country facing sharp spending cuts and tax rises after the government overspent in 2012, he acknowledged.
"We can do it with less, but it means the system will be less adequate," he said.
A senior naval commander, speaking on condition of anonymity, said that simply to patrol the area Israel needed four new ships and that it had already been in touch with eight or nine foreign firms.
Amit Mor, chief executive of Eco Energy and a former World Bank consultant, said Israel need not reinvent the wheel. Lessons on security can be learned from areas such as Nigeria and the North Sea and adapted for Israel's situation, he said.
"I trust that the Israel Defence Force has the ability to provide adequate protection for the new offshore activity and that the required funding will be allocated," he said.
THREATS AND TARGETS
It took 40 minutes heading west from the port of Ashdod to reach the two gas platforms on patrol boat 836, a fast-attack vessel equipped with high-tech radar and carrying a dozen sailors armed with M-16 rifles.
Israel's coastline, 15 miles (24 km) away, can be seen on clear days from the two rigs, serving the Tamar and Yam Tethys fields, which are nearer to the shore than the latest finds.
Also visible is the Gaza Strip, ruled by the Palestinian Islamist group Hamas, which has fired thousands of rockets into southern Israel. The platforms are within range of the rockets, although these are not very accurate.
The Lebanese Shi'ite militant group Hezbollah poses a more formidable threat. Last year it sent a drone deep into Israel, covering more than enough of the distance needed to reach some of the gas fields.
The group, backed by Israel's enemy Iran, also says its rocket arsenal has the range to hit anywhere in Israel, which indicates more sophisticated technology.
Energy-rich countries have for years been searching for the best tactics to defend their offshore assets, often isolated and vulnerable in the deep seas. Attacks have become more frequent.
Oil platforms off Nigeria have been hit repeatedly, and in 2004 suicide bombers launched coordinated boat attacks on an Iraqi oil export terminal.
"These incidents illustrate that terrorist organizations have become aware of the potential damage that may be inflicted through attacks on the offshore oil and gas industry," Assaf Harel, a legal adviser to Israel's Military Advocate General's Corps, wrote last year in a Harvard security journal.
The two Israeli gas platforms visited by patrol boat 836 have private security teams, which were notified as it approached.
The bigger of the two, which was completed in December and began production on Saturday, receives gas from the Tamar field to the north via a 150 km (93 mile) pipeline. Developed by a U.S.-Israeli consortium at a cost of $3 billion, Tamar alone has enough gas to meet Israel's needs for decades.
The smaller platform is for the older, nearly depleted Yam Tethys field and in time will become a sort of storage facility.
Most new drilling, like that at the Leviathan field, the world's largest offshore discovery of the past decade, is happening much farther from land, increasing exponentially the area Israel's fleet needs to patrol.
When the area is developed, companies including Russia's Gazprom expect to send multi-billion dollar floating liquefied natural gas vessels to the area to facilitate exports, and these too will need protection.
A clash with other navies is not likely. Initial bellicose exchanges over the gas fields between Israel and Lebanon, which have never agreed upon a maritime border, quickly subsided.
Lavi would not discuss details of each individual threat but described a broad, integrated defence strategy based on intelligence, deterrence and maintaining a strong physical and technological presence.
"We have a response for every scenario," he said.
(Additional reporting by Dan Williams; Editing by Anthony Barker and Jane Baird)