+1 on this any sailor reading it. The copyright on my copy is 1986, so it may be hard to find. But it has a couple of important things that I think are still relevant 20+ years later:
1. don't count on the "survival" supplies packed with the raft.
2. have an way to fix punctures in the raft, and re-inflate it, considering rule 1.
3. have a way to produce potable water, considering rule 1.
4. have a way to get food, considering rule 1.
5. How to improvise a sextant.

I think there have been other threads about life raft contents and their problems, as well as something Les Stroud did on one of his episodes that indicated a similar problem. I have no personal experience in this regard, but think that it should be possible to supplement a life raft's equipment with a floating, sealed (e.g. screw top) large diameter PVC pipe with reliable equipment inside and tied to the raft (or some similar concept), so it goes over the side when the raft does, and stays attached.