Boat engine data on an iPhone

Over the last couple of years there have been huge strides in the marine industry towards remotely accessible boat data. Seeing live data beyond the confines of your cabin has become easier. Proprietary Apps are a partial solution, but if you mix devices from a number of manufacturers, where is the App for that?

A year ago I couldn’t have imagined that I could write an App to calculate fuel economy for most brands of marine engines in real time. To have portable boat engine data on an iPhone, seemed wishful thinking. My dream is now reality with the new free Signal View App – discussed further below…

Signal K is Now!

To give due credit, you have to acknowledge the amazing work of the incredibly talented and dedicated Signal K team. What started with Teppo, Robert, Tim, Fabian, & Kees’ vision, has morphed into a nearly complete v.1 Signal K specification. This new free open source marine data exchange format is opening the door for many new innovations. The list of products using Signal K is growing daily.

I predict that Signal K is a landmark milestone that historians will credit for pushing the marine industry into the twenty-first century of technology. The convenience we take for granted every day in our Internet world, is now coming to boating.

To play a tiny role in this great push forward is fun, rewarding, and humbling. I say humbling because the more I learn about what is possible, the more I realize my own limitations when it comes to computer programming. If I can do it, then I can only imagine what will come when more skilled eyes turn their attention to Signal K.

One talented coder is Scott Bender whose Wilhelm SK iPad App is a most impressive example of how Signal K is leveraged to do some amazing stuff in IOS. Check the App out if you haven’t already.

Digital Yacht’s iKommunicate

Digital Yacht iKommunicate

Apart from Signal K coming to fruition and the formal recognition of the standard by the NMEA, it can be argued that Digital Yacht’s iKommunicate is just as important in making Signal K mainstream. If you don’t already know, iKommunicate is the first commercially available NMEA to Signal K gateway. Many of us backed the development on Kickstarter a year ago. Since release, it has been maturing rapidly via continuous firmware updates.

Digital Yacht – particularly Paul Sumpner, with Steve and John at Camanolight – has worked incredibly hard to create a great commercial product that is a swiss army knife of capabilities. The non-technical boater can now tap into their boat’s NMEA network and put navigation data into any number of commercially available Apps. Even if Signal K support hasn’t yet been added to an App, the iKommunicate can still feed it data. iNavX is an example of an App that isn’t yet using Signal K, but can still use native NMEA wireless data from iKommunicate.

Signal View

If you checked out the core Signal K team you’ll notice six self-professed sailors and no power-boaters. Perhaps sailors are smarter and more reflective – who knows? When I started testing my iKommunicate, I felt that it needed to be made a bit more accessible to the non-geek who doesn’t know JSON from a Jib.

Seeing as I’m a power-boater myself (I do love sailing though!) I thought I could bring a new angle to the movement. In some small way could I generate more buzz toward Signal K? Could I help accelerate the chicken and egg problem that comes with niche hardware and limited Apps? I set out to find out what my weekend coding skills might make possible.

The first thing to understand was what the heck was this Signal K formatted JSON data that the iKommunicate spits out? I learned it was actually easy to read, work with, and use in a mobile application.


Like many other boaters I carry my iPhone everywhere. It is very portable and it presents data quite efficiently. Why not design an App that doesn’t just display data, but also provides more functionality. There are times when you are away from the helm and can’t see your multi-function display. This is essentially the use case of the Signal View App. If you want to navigate with something, there is a lot better out there. However, if you want dock-side or back of the boat data viewing, Signal View will come in handy.

Signal View Functionality

Signal View App Settings Screenshot

Read on or go to the Signal View support page where there is a full description of this free App for iKommunicate. Note that the App will work with other Signal K servers but I won’t guarantee full functionality. I wrote the App for iPhone (IOS 9.3+) but you can install it on an iPad. It will look like a blown up iPhone version. I have an old iPad 2 and it works great.

Core features

Just like other Signal K Apps, Signal View can display live data from your boat. Nearly 70 different NMEA data types are supported with more being added regularly. The iKommunicate translates data from the proprietary NMEA 2000 format to the open Signal K format. Not all data is being translated yet. Check the list in my link to see what might be possible for your boat. I have included metric, US and imperial units with a settings page that will change the units appropriately in all parts of the App.


Signal View App Fish Screenshot

Every summer I jig for bottom fish of the back of my boat. Typically I move the boat to a suitable location. I switch off the engine and then drift until the situation requires me to reset position. I’m a big believer in situational awareness so I created a screen in Signal View that monitors depth, drift speed over ground, course over ground and drift distance.

As soon as you switch to the “fish” screen, the App calculates drift distance from that point on. An alarm can be set for a particular distance to wake you out of your fishing trance. An email can also be triggered if you decide to use the feature as an anchor alarm when you’re off the boat. You will need to leave the App running on board, so don’t forget to take another device with you to check email.  I personally wouldn’t rely on this feature with my boat, but if you have no other option then why not use it?

Engine and fuel economy

Signal View App Engine Data Screenshot

Please comment below if you have ever seen a power-boat fuel economy App that can work with engines from a variety of manufacturers? I believe Signal View is the first. Perhaps I will be corrected though…

There are two engine oriented screens in the App. The first shows the basics (oil pressure, RPM, alternator voltage) and monitors maximum engine temperature. The second is focused on calculating optimal fuel economy. The Signal K sailors will probably laugh at the need for this. However, power-boaters tweak fuel economy with a fervor that borders on unhealthy!

What I’ve personally never seen in just about all the engine data displays from Garmin, Navico, Raymarine, etc., is what I tried to create simply in one view. You set the speed at which your boat planes, then the App will calculate the optimal fuel economy above and below planing speed. I find the best way to use the feature is to slowly increase throttle in small increments throughout the power range. The App will measure fuel economy at various RPM settings and display the on-plane and off-plane fuel economy RPM settings where you get the best bang for the buck.

Displacement hulls

Signal View App Fuel Economy Screenshot

This is pretty cool and also useable for displacement hulls as well. You can pretend your boat will plane at a certain speed in order to achieve two sets of results in two speed ranges. The reality of most boats is that the absolute best fuel economy is below hull speed. More importantly there is a best fuel economy at some speed above planing speed (for planing boats). I’ve tried to make it easier for you to get to know your boat better! There is also a button which will calculate your maximum range based on the best fuel economies the App has seen.

Dual engine support calculates fuel economy for each engine. If you feel brave and don’t mind knowing how much your boat’s thirsty engines are burning, you can view fuel economy and usage for both engines at once.

Custom screens

Signal View App Custom Screens Example

The most used area of the App will likely be the four custom screens that show four data types per screen. An easy to configure wizard walks you through picking what you want to display. As I mentioned earlier, you can even have the App send your data to specific email addresses if you wish to analyze it later. Custom labels can also be set to rename the data to something more meaningful. A finger tap to the ever-changing data pane will always show you the actual data type that was originally setup.  One great use is to monitor tank levels while filling up at the dock. Your boat’s wireless router should have more than enough range to ensure that you don’t overfill.

iKommunicate specific features

Signal View App Tools Screen

There are a few things that the App can do that were built specifically for the iKommunicate. The App quickly finds iKommunicate on your network and connects automatically. This saves a bunch of time when you want to get going and it checks the connection at the same time. The can also turn on and off the internal logging of the iKommunicate. Digital Yacht might need this internal log for troubleshooting. Digital Yacht uses it to fix problems and also learn how to translate data for marine devices they have never seen before. Downloading Telnet software and hooking up a laptop is no longer needed.

The App will also show you how much room you have on the iKommunicate’s internal SD card. Finally there are direct links from the App to administer iKommunicate, along with more to discover. Don’t forget to set your boatname and MMSI number in iKommunicate’s administration interface if you haven’t already done this.

Social media boasting and safety

Signal View App Send Location

The App takes navigation position data on your network – usually much more accurate than your iPhone – and with a few finger presses you can send a message, email, or even post to twitter with an included google map link. If you have no lat/long data on your network then the App falls back to using the iPhone’s own location data. In an emergency it only takes seconds to get your location out using the App. Please use the VHF radio first though!

Gear Needed

If you have an iKommunicate connected to your boat’s NMEA 0183 data stream or NMEA 2000 network then you can use Signal View. You will also need an inexpensive wireless router connected to the iKommunicate in order to connect your iPhone. An Internet connection is not required to use the App. An outside your boat data connection is only needed if you want to use the built-in automatic email feature which can send your data at the frequency you choose.  Please make sure you update your iKommunicate to the latest firmware using the automatic update feature in the administration web page.  The recommended version is February 15th, 2017 or newer.

Enjoy the App and please give me feedback so I can keep improving it. It’s free after all!


  1. Good morning,

    I am excited and impressed with what you are doing with Signal K!

    Thank you from a fellow power boat!
    Dalton Williams
    DeFever 41 Easy Living