Well those are the type of answers you will get when one has no idea what they are talking about!.
YES Submarine do have life rafts, inflatable ones. Currently the US uses a SEIE Suit (Submarine Escape Immersion Equipment) This is a full body suit with a full hood a Submariner can use either for a buoyant asscent (escape while the sub is on the bottom in shallow water) or if surfaced to be able to abandon ship. It is completely waterproof and each has a one man auto inflate liferaft, with air cushions to keep you separated from the cold water to prevent Hypothermia.
Prior to this we used a Stenkie hood, a life vest with a face cover for buoyant asscent, but had no life raft. The Submarine was equipped with two 8 man liferafts during those days. They would have been used for the most seriously injured only, but if you had to escape in cold water most would be lost from hypothermia in short order.
Sure these are rubber inflatable, but that is the standard for all vessels. If you look at warships or even cargo ships and cruise lines you may see these canisters about 3'x2'. These have 25-50man rubber lifeboats that can either be manually detached or will automatically detach if the ship sinks and inflate.
Here is a link showing the Suit and in the 7th photo down you can see a getting in the one man life raft.
http://www.navsource.org/archives/08/08451.htm
Submarine rescue equipment is not new. The Momsen Lung and Crude escape Bell from the 30's was the first attempt to enable submariners get to the surface from a striken vessel (lesson learned from the Squaillus). But it has come a long way since then to the SEIE suit and RORV we have today (the DSRV's have been retired).
ADDEDD
About the comments if you asscend to quickly you die, blah blah blah. Well our ESCAPE TRUNKS (2-3 on each depending on class of sub) are designed to minimize exposure to pressure for just 2-3 seconds before ascent begins. They have been tested to over 400 feet with no ill effects of those who asscented.
Rescue Subs or Rescue Bells are prefered but a bouyant asscent is also available in shallower water (over 400 feet). No your lungs will not burst as long as you breath on the way up (hence the reason for the hood to keep air around your head), your organs will not explode, the worst is possibly decompression sickness, but unlikley giver the very very short time at pressure, or possibly ears drums rupture do to rapid decrease in pressure and inability to equalize with your head covered, though a nose plug is provided to aid. This would be painfull, but not even close to fatal. The main threat is hypothermia, and dehydration if rescue is days off.