For those people who want to converse with family and not pay for internet or messaging on the ship.

[MuttMutt]

I may have found something that will work for you and I actually want to try it sometime.  

 

Anyway there is a project that is geared to long range off grid communications called Meshtastic.  There will be some initial cost but it's pretty much a one time deal and can be utilized outside of just being on the ship.  The boards are about 30.00 each and will require a touch of soldering to attach the screen but once that is done it should be pretty well good to go.  

The device is battery powered and with line of sight can function at a distance of about 11km or 6.8 miles.  Naturally on the ship this will never be as far but I suspect it will work throughout most of the ship.  The software communicates with your phone over bluetooth so you will need one for each person involved and it probably would not hurt to have one in your room to act as a repeater especially if your room is close to the middle of the ship.  But the potential is there for free text based communications.

 

I literally just found this project and have not had the time to get anything setup but once I do I will report back if there is any interest in others using this as well.

 

https://meshtastic.org/ is the project website for anyone interested.

[AspiringCruisePlanner]

I've seen suggestions for mesh network solutions like this. I'm skeptical of the practical range in a cruise ship between floors.

The most practical/promising one I've found online is this bear tooth device. https://beartooth.com/ It has a similar line-of-sight range of 10 miles, and only one device can be hooked up to it at a time. It does double as a walkie talkie which I'm aware is not appreciated onboard in public settings.

There's another one called goTenna that's similar but has a lower claimed range. Some guy shared his experience with them on a cruise ship in a forum. https://community.gotennamesh.com/t/cruise-ship-project-and-test/2831

What's really interesting to me is mesh messaging using an app like Briar or Bridgify (Android examples). I'd guess if even 20% of people on the ship had the app active, you'd be able to communicate no matter how far you were away from them, no extra device or internet plan needed. It'd actually be a big move by Apple or Google to introduce this into their platforms.

I have hopes for this tech to make progress in the coming years, but my take is that it still needs some traction to really take off.