Knife Sharpener

[Birddog 2]

A couple of weeks ago there was a thread about knives and which are best for filleting. As a result I went and bought a couple of the Dexter 1378 knives. Found them at a really good price at a restaurant supply place on the internet, about $13 each. My question is what do you guys use for a really good knife sharpener on you boat? I've tried a couple I found at West Marine or Dicks but none of them really sharpen well. I end up bringing my knives home and using a small sharpener clamped in a vise that works pretty good. Any suggestions?