Great question. The biggest difference is how your computer is setup on the network. I can only speak for the windows world as I'm not that familiar with apple or linux
systems. Your network settings are configured as either home, work, or public networks. Most people when connecting to a public wifi
system are going to set it as a public network, which is going to give you the best "out of the box" protection. It also means you won't be able to share files, etc, over that network, but who cares, you're just surfing the web. However, I would be willing to bet that 99% of the people who have wifi
systems on their boat have that one configured to home, which gives you NO protection. Actually it pretty much opens your computer up and screams come get what you want, because that network is designed for easy communication between computers
. Or computers
and other devices. It's why your TV can stream movies stored on your PC. Or why you can open a spreadsheet on your laptop
that's stored on your PC. Or how your iPod has access to your iTunes library. If you only have one device that connects to the wifi on your boat, making sure that connection is set to public would probably be ok, but if you're like me even on a boat I would probably have half a dozen devices connected. I probably have close to 20 on my home network.