The ability to connect to the internet from our boat is very important to us.  Let’s face it, the internet is such a fabulous resource that it is worth the time and effort to make sure we have the best connection possible.  Even if you don’t care about reading your email or posting to Facebook, the ability to access weather, anchorage information, or YouTube videos about how to bleed a diesel engine or some other maintenance issue makes the internet an important part of good seamanship.  The challenge on a boat is that we are continuously moving from one spot to another and are usually further away from any internet “hot spot” or cell tower than if we were on land.  There are also two types of internet access: WiFi hotspots and cellular data.  Both have their advantages and disadvantages.  WiFi hotspots usually have a password requirement, but if you have the password, the data are free.  A typical example is a marina WiFi.  The downside is that 100s of other boaters may be using the WiFi also and things can get pretty slow.  There is also the security risk of using a public WiFi: anyone with a packet sniffer can steal passwords, credit card numbers etc.  The remedy is to use VPN software to make your connection.  Cellular data is generally safer, and faster. Cellular data has a much longer range and you can generally receive a cell signal 4-5 miles off shore of most areas in in the US.  The downside is, most cellular data plans have some sort of cap on the amount of data you can use before they slow it way down.  For these reasons, it is best to have both capabilities on a boat.  After doing a ton of reading of Cruisers Forum and other blogs, I settled on a DIY system for Terrapin that does the following:

It has a long-range WiFi radio/antenna on the stern rail that is capable of connecting to WiFi hotspots several miles away.

It has a high gain cellular antenna also mounted on the stern rail that is connected to a dedicated cellular modem inside the boat.  We can and do sometimes use our cell phones as hotspots also to connect, but the high gain antenna can pick up cellular data signals at a distance when cell phones cannot connect.

Both of these are connected to a basic router inside the boat that any device can log into and receive the internet from whichever connection is chosen.  This can be selected by a simple switch.  When we move from one location to another and need to log into a new WiFi hotspot, I can access the long range antenna through my laptop, and see all the available WiFi connections in the area.  If I have a password, e.g. from a new marina, I can log into that WiFi.  The connection on the boat remains the same.  All devices  simply log into the boat router with a single password.

For anyone wishing to set up a system like this, you can download the PDF file below with complete instructions on configuring such a system.

The WiFi installation on Terrapin. The Netgear 4G modem is on the right and the Netgear router is on the left.

A closeup of the installation showing the WiFi/cellular switch on the right and the POE injector for the Bullet on the left.

Configuring a boat WiFi network