Most people don't realize that almost the entire French and British nuclear arsenals are located aboard their strategic submarines. This article in the Guardian details some improvements the French are making in their nuclear deterrent force:
"The source said there had been two major changes: the bombs can now be fired at high altitude to create an "electromagnetic impulsion" to destroy the enemy's computer and communications systems; and the number of nuclear warheads has been reduced to increase the missiles' range and precision.
"During his surprise speech, which was made in January, President Chirac said: "The number of nuclear warheads has been reduced in certain of the missiles in our submarines".
"Military experts said this was not a step towards disarmament, but a move to improve the performance of the weapons. Until now each submarine carried 16 French-made M45 missiles, each fitted with six nuclear warheads. After being fired, each warhead would separate to hit a different target, in effect giving each submarine 96 nuclear bombs.
"In reducing the number of warheads, down to one per missile in some cases, the weapon is lighter and has a longer range. It can also be targeted more accurately."
The French are the only Western country continuing to build SSBNs, although the Brits are in the middle of a debate about how to modernize their boomers. With the exception of a few air-launched missiles, the French nuclear force is based almost entirely aboard the four submarines that make up the Force Océanique Stratégique: the aging L'Inflexible (S615) and three Triomphant class boats. (A fourth Tripomphant, Le Terrible (S 619), is due to be launched in 2008, and will reportedly join the fleet in 2010 with the new M51 missile as part of her initial loadout.)
Say what you want about our French allies, they give good names to their submarines.