Timothy
It has been variously claimed that the average time between engine failures is 3000-10000 hours, so if you have had "loads" of failures you either must have tens of thousands of hours, or have been very unlucky.
What has caused all these engines to fail? Do you fly vintage aircraft?
Re the original question, I discussed this recently with a liferaft manufacturer. They agreed with my suggestion (which I base on watersports experience) that if the raft is in the water and you are not holding it, it will very likely float away due to wind faster than one can swim after it. So one must hold onto it. I would try to get the raft out onto the wing and inflate it there, then both people get into it.
Having had a door lock jam in a PA28 (on the ground) I would definitely try to pop the upper lock at least before the impact.
What does one do in a high-wing plane??
The statistics don't appear to favour low-wing planes, which is suprising.