A:Answer No.
This is not a WiFi device.
This is a landline phone basically. It does not have wifi capability. You can plug in 2 landlines. Also, 2 cell phones can connect via BLUE TOOTH to this hardware so you can answer the cell phones from this hardware on any extension. Like any landline phone with an answering machine and additional extensions, each base and it's extensions need to be plugged into an AC power source - like you have in a home on land. I imagine there must be some sort of electrical source on your ship. If your cell phones work out to sea on the ship and you do not need WIFI for that to happen, then the cell phones can be used from the base and from the extensions. However, if the cell phones work WITHOUT this base, then you don't need this to make calls.
If you are looking for this to work without using your ship network WIFI, to make calls, no it won't do that. It's not much different than any phone you might buy for a home on land.