In my opinion, swimming is not an issue. In a "man overboard" situation, I don't think one has anywhere to swim. To swim to catch the boat is more or less impossible. One need to hope that one will be missing and that a MOB-alert is issued. This will take some time, so one will need to keep warm and be afloat as long as possible.
The best thing is of course not to fall in the water. That is why many sailors rather use a lifeline to attach themselves to the boat so that they never leave the boat.
Even if one manages to be warm and keep afloat, the problem of being able to reenter the boat still remains. It may be useful to try and reenter the boat fully clothed.
Use your head, ram the wall till it falls.