I was looking into Wi Fi antenna systems for boats today. We decided to purchase the Bitstorm Inc Bad Boy Xtreme. Not only because it sounds intense, but because it seemed simple to install. It came as a kit. It came with an antenna with internal ethernet device; this increases the signal by reducing the distance of TV cable, and therefor reducing loss through the cable. Then It directly wires into your busbar 12 volt system, and plugs into your computer using lower loss ethernet cable. We went with a wireless router that directly connects to the setup so we can use all our wireless devices on the boat. So that's now off the list. Many more things to go.

It had pretty good reviews, but I'll let you know how it goes when I install it.