“Sorry, please get yourself a book on basic statistics.”

Got plenty thanks.

“Probability is defined exactly as I described. There is no way you can predict events. You can only count past events and then project forward.”

Probability is about expected outcomes based on existing data. As there have already been Liferaft incidents then likelihood/chance of future incidents is non zero unless you intend to bias the sample by removing inconvenient data.

“I can say that on the basis of the evidence there is a 60% chance if you are hit by a ship your boat will disintegrate and 40% chance that it will stay afloat long enough for you to be rescued or take to your liferaft. This is based on total of 5 reported incidents. I can also say that in a planned evacuation there is a one in three chance that the liferaft will not inflate. Based on a sample of 3, all with very different causes.

Now you should see why statistics are useless in understanding this issue.”

Except we are not talking samples here, this is population. In the first case, we are looking at 5 incidents out of the total population, so it is perfectly acceptable to to make those statement. In the second case you are making predictions based on a small sample size and should couch your statement in terms of the Confidence Intervals and the Power of the test. Unsure as to why you think that this makes Statistics useless.

“Imagine how the daily papers could present the figures

"3 out of 5 yachts disintegrate in collisions!!!"

Somewhere at the bottom they might say that there have been only 5 collisions in 12 years, and probably would not bother to explain that an 8 metre yacht does not stand a chance against a 15000 ton ferry.”

That is Newspapers for you.

“You can sail all your life and if you don't go near big ships, don't go out in extreme conditions and have a sound ship the probability of you needing to use a liferaft from the data available is in fact zero.”

For certain values of “big”, “extreme” and “sound”. The problem is most sailors will have to go near big ships at some point, will get caught out when the weather deteriorates and will have unforseen problems with their boat.

“As to your last point, yes you can prevent foundering by not getting into situations where it might happen. However while we continue to cross the channel and dodge ships there is always a chance that a collision will occur. The fact that it happens so rarely suggests that everybody is fully aware and takes precautions, Radar, AIS, Mk1 eyeball etc.”

Yes.