I think that it is certainly a bold prediction but not impossible. It goes back to their plan for a sales force. If they start offering their products through multiple distributors I believe they could reach that number. I'd be happy if they reached a quarter of it!
your approach doesn't make real life sense. WLAN would be going to companies that own or manage multiple marinas...not walking the docks looking for a marina board member to chat with.
i'm in the marine industry, just trust me on this one.