We use a Ubiquiti Bullet
, which is easy to mate with a nice antenna on the flybridge. Ethernet cable to a Wifi access point below (we use an old Apple Airport Extreme, which still works great) and voila, your boat has its own wifi that you can connect to another wifi network from many hundreds of yards away. Even when you can't connect to the internet, the wifi is useful to link, say, a Roku to a Synology NAS acting as a video server.
The Ubquiti device and a 4ft antenna will maintain a strong link to the marina wifi (or a phone hotspot, for example), and the wifi access point will share that link with devices on the boat.