satellite phone
From 2016 to 2020, we used a Iridium GO! satellite phone to relay our position to our land crew (Devine's dad), and to communicate with our friends and family via SMS & emails, from anywhere in the world—even the middle of the ocean. We used again for a trip to us se alaska in 2024.
Satellite phones lists positions in Decimal Degrees(DD). To convert positions to Degrees and Decimal Minutes(DDM, the coordinate format Navionics uses), use this formula:
There are 3 different coordinate formats: Decimal Degrees (dd.dddd°) Degrees and Decimal Minutes (dd° mm.mmm') Degrees, Minutes and Seconds (dd° mm' sss") ° : degree (D) ' : minute (M) " : second (S) DD : Decimal Degrees DDM : Decimal Degrees Minutes DMS : Decimal Minutes Seconds 1 minute is equal to 60 seconds 1 degree is equal to 60 minutes(3600 seconds) ------------------------- Formula for DDM to DD: DDM = D + (M/60) Example: To convert 124° 44.740, a DDM coordinate, to DD 124.746 = 124 + (44.740/60) And so, 124° 44.740 DDM is 124.746 DD ------------------------- Other: Formula for DMS to DD: DD = D + (M/60) + (S/3600) Example: To convert 43°26'8.03652"N, a DMS coordinate, to DD. 43 = D 26 = M 8.03652 = S 26 / 60 = 0.733 M 8.03652 / 3600 = 0.206 S 43 + M + S = 43.43556570 And so 43°26'8.03652"N is 43.43556570 in Decimal Degrees.
Satellite phones are an expensive option (costs around about 100US$/month), and should you choose to go this route we recommend getting an unlimited plan, because data minutes run out quickly. The Iridium connects to overhead satellites and demands a stable connection to download weather data, like GRIB files, or to fetch webpages.
Iridium Mail and Iridium Go! applications. We used the Iridium Mail and Iridium Go! apps to make requests. The Iridium Go! app is useful to send quick sms messages. We used Iridium Mail to send emails to request weather, or webpages.
Making a data request
Step 1. We would connect our old Ipad to the Iridium Go unit via Wifi, if the Ipad is connected the Iridium Go unit will show a little 1 in the overhead bar on the screen, otherwise it will read zero.
Step 2. If using the Iridium Mail application the Iridium Go application must be opened first, and the connection needs to be green(on the top left part of the UI).
Step 3. We send an email, then start an internet call on the Iridium unit. The device needs to register more than 2 bars of signal to make a successful call.
Step 4. Once the signal is good and that the internet call is in progress, click Get mail and wait for the transaction to go through, it can take a while. The application may send the email and then receive the reply right away, it may send the email and fail to finish the transaction(note that if it fails, it still uses up data), if this happens you will have to press get mail again.
Step 5. Once you receive the reply email, and that the log tells you the transaction is finished, close the internet connection on the Iridium Go unit, or fold the antenna down, doing this will shut down the device.
Sending Images via Iridium Go
Can you send photos and documents with it? Yes, but it takes a long time, and requires a stable connection. Plus, the documents and photos need to be as compressed as possible, while being readable.
We had to send authorities in Ogasawara, Japan, passport scans, and entry documents after first sending it to the wrong office, had we not done this they would have fined us on arrival. It worked in the end, but it took a while (had many failed uploads). Don't even think of sending data like this without an unlimited plan.
Requesting Webpages
While in Canada and the US, we occasionally bought 200-minute data cards from third party vendors to be able to get weather. Once activated, the data card expire after a certain time(for us, 6 months after activation), even if you haven't used up all of your minutes.
Some anchorages in northern British Columbia and Southeast Alaska don't always have VHF reception. We would get weather data by requesting webpages from Saildocs, an email-based document-retrieval system, by sending an email to:
With send in the body of the email followed by the requested webpage. For example:
send http://100r.co
To receive an email with all of the available commands, send a blank email to [email protected].
Do not add capital letters if there aren't any, and don't add extra spaces, or make lineskips, or the command will not work.
grib files
On our 5-year circumnavigation of the Pacific Ocean, we used GRIB files (Gridded Binary data files) to read the weather.
They are computer-derived weather forecasts packed into a digital file. They are compressed versions of the weather data found on weather forecast websites, 1/2 to 1/3 of the size of the normal binary files. GRIB files can be quite large, so it is therefore necessary to specify an area of coordinates with an appropriate resolution to keep the files small, the transfer fast and the whole transaction not too costly.
When downloading GRIB files, you have the option to select extra parameters, such as Wind, Rain, Wave, Cloud, Temperature, Sea Surface Temperature and Current.
We download them using our SAT phone's data by way of saildocs. Documents are requested by sending an email to: [email protected]. Saildocs is an automated system and the format for an email grib request must be followed exactly. Follow this tutorial to find out how to write weather data requests.
An example of a request email for a GRIB file:
send gfs: 55N, 57N, 135W, 137W
After successfully downloading the GRIB file, we connect to the Iridium GO with our laptop or phone, and visualize them using the free version of PredictWind.
Our experience with the Iridium GO
On our South Pacific run, we had an unlimited data plan, which worked out quite nicely, but it wasn't cheap.
During our north pacific ocean crossing, we bought blocks of data that we thought would be sufficient for a 2-month long sail, but we ran out at the start of the second month. Our connection was often poor, and the Iridium continues to gobble up minutes even when failing to send or receive data. Getting additional data was complicated, and expensive. We let our unlimited plan expire in 2019, because we knew we wouldn't be sailing offshore for a while and would not need it then, but SIM cards expire when you don't use them, and when renewing a plan you need to buy a new card, and have it shipped to you—which may be difficult, depending on where you are in the world. It is why people like to leave with multiple cards, so they are never stuck. A new card means paying for a high activation fee.
A satellite phone is handy at times, but not perfect. The Iridium GO companions apps for phone are absolute garbage, and was, and continues, to be a serious point of friction for us.
What about Starlink?
When considering such a service, it is important to remember that relying on a centralized service can be problematic, because services have rules and owners and processes which can complicate things.
For instance, country politics have made it so that Starlink, or local governments, can choose to restrict access. Currently, Starlink is blocked in Russia and China by local governments, and US negotiators recently(Feb 2025) threatened to cancel Starlink communication in the Ukraine to bully president Zelenskyy into signing a mineral deal. As conflicts arise, this will continue to happen.
In all though, we want nothing to do with Starlink, it is owned by a narcissist that uses his obscene wealth to fund right-wing extremists in the US and abroad.