If you are serious about learning about libertarian theory, I would suggest not starting with outliers for moral situations. Here are two resources for you to learn the basics:
The Ethics of Liberty by Murray Rothbard
In it, chapter 20 focuses on the lifeboat situation, but I suggest reading the entire book first.
What Law Is by forum poster Clayton
I highly recommend reading these before starting in on lifeboat situations. You need a firm understanding of the basics before you start to tackle complex situations.