Phone and wifi booster help

[Trebby12]

Hi
I Need a wifi and phone booster that will work on the "3" network.
I live on a boat I do not need a booster that gives me loads of coverage I just need something to boost the incoming signal from the mast.
Most booster I have looked at seem to quote the mega amount output area covered from the booster which in my case is not needed.
Any advise?

 

[DelJo63]

The "3 network" is not an issue, but the RF strength sure is - - similar to an RV problem, like this or this.