Category Archives: Terrapin upgrades

How do you get internet on a boat?

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

Update March 17, 2018

New helm seat

Awesome chart plotter

We started our 6 week Spring sailing adventure about a week ago and spent the last week at Fisherman’s Village Marina.  I finished a bunch of upgrades that have been ongoing on Terrapin since I bought her last May.  The most important is the modernizing of the electronics and navigation systems. This includes a new chartplotter mounted at the helm.  It is a so-called multifunction display which means it can process and display data from any device connected to it; wind direction, wind speed, AIS, compass heading, rudder angle, autopilot control, GPS position, and of course the chart showing where we are.  This is all made possible by a new industry standard connectivity called NMEA 2000.  There is a single cable (backbone) running down the mast from the wind speed/direction sensor all the way to the stern of the boat. Each device is then connected to the backbone with a T connector and a short “drop cable”.  The result is that every device has access to all the data in the system.  Laura calls it the spinal cord, a good analogy!  Well, I spent about 5 days hooking it all up and surprise, surprise, it all worked! I also installed a new helm seat raised up about 5 inches so we have a better view, a new toilet pump, and a bunch of other minor items.  We also had a visit from Mack Sails to adjust the rigging.  The original head stay was supposed to be adjustable and somewhere along the line, a fixed length stay was installed.  This meant you could not adjust the tension, and thus the angle of the mast.  Mack Sails, who installed our new sails last November, came out and added a turnbuckle to the head stay and helped get the rigging adjusted properly.  I can’t wait to sail her, there should be a big improvement.

Prop Pitch Matters

Terrapin prop after re-pitching

When you run a boat under power, the prop size and pitch needs to be matched to the maximum speed of the boat as well as the maximum rated RPM of the engine.  In other words, at wide open throttle (WOT), the boat should reach its maximum (comfortable) cruising speed and the engine should be operating at its rated maximum RPM.

Our PDQ 32 LRC has two Yanmar 2GM20f Diesel engines, each rated at 18hp at a maximum RPM of 3600.  So, at WOT, the engines should be able to operate at about 3600 RPM and the boat should reach a speed of about 7 knots.

When we bought the boat, she had upgraded 3 blade props (considered more efficient and smoother than the stock two bladed props).  However, when motoring on smooth water, the engines would only achieve 2800 RPM at WOT.  In addition, there was smoke in the exhaust indicating the engines were laboring too hard.  The analogy would be driving a car up a hill in 4th gear.  The car would go, but the engine would be lugging and operating at a suboptimal RPM. If you downshift, the RPM goes up, you have more horsepower, and the car runs more smoothly.  The term for this in boats is being over-propped. This is due to the pitch of the prop being too steep.

Fortunately, there are propeller specialist shops that can re-pitch props and they have sophisticated computer programs to determine the optimum prop pitch based on your boat, transmission and engine.  I used Coastal Props in Fort Meyers.  The existing props were 15” in diameter with a pitch of 12. After consulting with Coastal Props they ran the info through their program and decided that the pitch needed to be reduced to 9. I removed the props when the boat was on the hard, sent them to Coastal Props and they re-pitched, balanced and polished the props for $135.00 each, a bargain.

The improvement in engine performance was dramatic. I can now get almost 3600 RPM at WOT and comfortably cruise at 3200 rpm, much closer to the peak HP of the engines. The engines run much more smoothly and no more smoke! Diesel engines also need to periodically be run at their max rated RPM to burn off carbon from the valves and exhaust. The re-pitched props now allow me to do this.  Thus, for a small investment, I believe I have greatly increased the life of the diesels on Terrapin.