Tom;

I'm a mathematician by training, and an IT security consultant by profession, and most of what I know about survival comes from reading this forum, so you've already had far more knowledgeable folks than me comment on your selections. I guess the only suggestion I could come up with that hasn't been given already is that the two life rafts with PLBs aboard should be separated as widely as possible, to reduce the risk that both will be destroyed by the same event. Alternatively, they should be in the locations that are statistically the most likely to safely deploy from, if such statistics exist. (For example, a life raft in the bow of the ship might not be accessible if there is a fire in the forward part, whereas a life raft amidships would probably be accessible from at least one direction.)

Mathematically, there's a thing called the law of diminishing returns, which I'm sure you're aware of. Basically, it states that if you can save 100 lives by spending a million dollars on safety features, you will save maybe 150 lives by spending two million, 175 by spending three million, etc. Some people argue that if spending an additional ten million dollars will save even one life, it's worth it, but where do you draw the line?

I always figured that the cost of a human life should be measured in other human lives. If your "safety measures" will save 1 life, but will be just as likely to kill 2 SAR personnel, then it's worth than a waste of taxpayers' money. Your example of putting a PLB on every life raft becoming a safety hazard when they all go off at once, for example. In the Sydney-Hobart Yacht Race disaster, several yachts were evacuated with the emergency beacons still transmitting, which resulted in multiple SAR crews investigating the same yacht, long after its crew had been rescued.

So if anyone criticizes you for not putting in their favourite piece of gear, don't lose sight of the trade-off in safety that results from adding "just one more thing".