If you want to cut down on the web traffic and get instant access to your pictures you might consider setting up a simple web server like apache and having that server send an email every hour or so of just the ip address. Then on demand you can call up that ip address and look at your boat at that moment.
The idea of a smart phone doing this is interesting. Android phones do not need to have a sim card to work with wi-fi. I wonder if there is a app that would do this. You could then buy an old generation. A Nexus One is about 300. You could even take flash pictures if the app allowed it.