In case you’re wondering whether the current climate of international tension and uncertainty is beginning to spread, one good indicator is the rising sales trends for convention (i.e. non-nuclear powered) submarines. The Wall Street Journal has a long report this weekend on the subject which is definitely worth a read. Sales of these next generation subs are projected to double what was seen in recent years and one of the biggest benefactors of this “boom in boomers” is Saab.

The Swedish government, upset with German ownership of Sweden’s biggest shipyard, last summer compelled ThyssenKrupp AG to sell its Kockums operation to Sweden’s Saab AB. The move, which ThyssenKrupp calls “unfair,” cost the German industrial group a billion-dollar submarine contract and hundreds of skilled engineers.

And Sweden’s maneuver established defense contractor Saab as a new rival in the global submarine market. ThyssenKrupp, the world’s top nonnuclear-sub maker, already feels heat from newly active producers in Japan and South Korea, and from old rivals in France and Russia.

The list of countries either getting into or expanding the global submarine force includes a few ominous entries.

Stealth makes subs particularly appealing to countries feeling threatened by larger rivals. Vietnam is buying its first subs, from Russia, while Australia, Indonesia, Singapore and South Korea are expanding their fleets—a response, in part, to China’s expansion of its navy with ships including its first aircraft carrier and large nuclear subs.

Iran has said in state-controlled media it is developing conventional subs to enhance its Russian-built fleet. Firm numbers aren’t available—countries guard their military plans—but at least 17 nations have made public plans to create or expand sub fleets.

I’ve never really paid much attention to the conventional submarine fleets, mostly because I suppose I’ve still been stuck in the mindset of cold war when I was in the Navy. Diesel subs were always out there, but the “big boys” in the game didn’t tend to give them a lot of thought. They couldn’t stay submerged for very long and tended to be noisy, making them easy to locate, identify and neutralize if need be. It was mostly a largely unseen game played by a handful of nations with nuclear boats, led by the United States and Russia.

But as you’ll find in the Wall Street Journal article, the new generation of conventional subs are very impressive indeed. They employ hydrogen – oxygen fuel cells in addition to their improved diesels, and can run in almost absolute silence for extended periods. The Germans had one stay under for eighteen days without firing up the engines, (allegedly not the limit of their range) which is enough to give superpower war planners pause. And assuming they’ve figured out the cavitation problems with their propellers, while running on those fuel cell powered batteries, they could be extremely difficult to track. There aren’t any details given about what sort of offensive capabilities they’re packing these days, but it’s not difficult to believe that they are more formidable than they used to be.

Submarine warfare is a lot more complicated and fraught with potential peril than meetings between surface ships. Getting this sort of technology into the hands of some countries who don’t like the west much to begin with, particularly on a large scale, adds disturbing new levels to the international diplomacy situation.