Answer:
Assuming there is absolutely no way to save the lifeboat (i.e. plug the holes, etc) I would try to break part of the boat off. This would serve two purposes:
1. Give me something to hold onto and float. The boat as a whole will sink, but a single plank or piece of wood will float and provide you some support.
2. Possibly serve as a weapon if the sharks attack.
Once the boat was sunk I would remain as calm and still as possible. Sharks are attracted to movement and blood so hopefully I'm not bleeding and I can remain calm.
If worst came to worst, and the sharks attacked, I would attempt to hit/gouge their eyes and gills. Sharks are most vulnerable in those areas and they don't like to fight prey that will hurt them back.
