If you are a computer literate, game playing kind of guy something that might help you to work out what knowledge you have gained while wasting away the hours is:
Virtual Sailor : PC sailing game - Free PC Download : Free Arcade Games @ winpcware
You don't get the wind in your hair feeling, but you do see how boats react and what works and doesn't. It's not real, but it beats surfing porn.
Of course there are more than just this one, it's just an example.