While Japan is confident it has proven itself the best contender to build Australia’s new submarines, the French have moved to undermine Japan’s bid to build the navy’s new submarines.

Representatives from Mitsubishi Heavy Industries (MHI), the co-builder of Japan’s Soryu-class subs, toured ASC’s shipyards in Adelaide on Tuesday. MHI chief executive Shunichi Miyanaga says Soryu-class submarines have proven capability, unlike the untested French and German designs. “We have the only proven submarine,” he said.
The French counterpart said only a “complete submarine power’’ such as France can provide the strategic partnership Australia needs for its future defence. 
The head of France’s DCNS Australia Sean Costello says Australia and France are now fighting side-by-side against Islamic State but this strategic engagement will be entrenched for decades at an unprecedented level if Australia chooses to buy its new submarines from France.
France is a complete submarine power and has national policies to remain so, said Sean. A complete submarine power is one that can safely ­design, build, operate and sustain any class of submarine on an ­enduring basis.
Meanwhile, FT reported that Paris’s bid to build a $35bn submarine fleet for Australia has lost significant ground over fears the French state shipbuilder will not be able to protect highly sensitive US military secrets.
The US military is concerned that submarine maker DCNS may be more prone to technology “leakage” than contractors in competing bids, according to several people close to the situation.
France is in Nato, the politics are delicate and it is true that US weapons have been integrated on to French vessels before, says the report.
For Australia, cooperating with Japan — whose Soryu is widely seen as the best submarine of its type — risks angering its biggest trading partner China. 
According to the report, Japan is offering to build a new Soryu with its hull extended six to eight metres (20 to 26 feet) to carry more batteries and fuel to take account of the massive distances the Australian navy travels.
Source: Marine Technology News