I'd be curious to see what ranges you actually get. First, because in order to get "range" you may
need extra power and sensitivity at both ends--not just on the boat. But second, because of "latency delays" in the router setups. That is, each Wifi set (your card and the router you are conecting into) is programmed so that if it experiences too great a delay between sending and receiving packets--it will drop them and ignore the transmissions. The delay (if anyone else remembers the NASA radio
casts from Houston
to the moon landers) is caused by the distance between the two units, and cannot be changed. What some
routers allow, is for a user to reprogram them to accept larger delays.
That kind of reprogramming was critical to setting the Wifi line-of-sight land distance record
, which is something like 125 miles at this point. But without reprogramming (which most routers simply won't allow) there are much lower limits--offhand I don't know how low.
I suppose it is also worth adding: radio
isn't just radio. In the US, licensed amateur radio operators are allowed to use more power on WiFi than "civilians". Both have limits. I'd expect limits apply no matter where you go--and some other countries are way stricter than the US, about confiscating "all related equipment" which could conceivably include the whole boat. They don't just ask for a small fine.