By Marcin Wojtyczka

11 minutes read

Read to decide on the best long-range communication options for ocean voyaging and learn how to use them.

Once you start venturing out of sight of land for more than 3 days you are likely to benefit from a long-range communication system. They can be used afield to contact family, download weather forecasts, receive / send emails or make safety phone calls if needed.

There are two main options available for long-range communication: Satellite or High-Frequency radio (HF). The only system registered with the Global Maritime Distress and Safety System (GMDSS) that provides voice communication services is the Inmarsat satellite system. Other companies (such as Iridium) produce shipboard equipment but are not part of GMDSS yet. Inmarsat is very popular within the commercial shipping industry. But Iridium is usually a better option for recreational sailors. HF radios are in decline due to the high initial cost of the equipment and complexity of use. A new emerging alternative is Starlink Maritime which offers up to 220 Mbps download while at sea. This opens up a new remote working possibilities.

Comparison

HF Radio (Marine SSB or HAM)

Advantages

  • Free ship-to-ship and ship-to-shore calls
  • A DSC-enabled HF set will mean you can broadcast a distress alert globally
  • Radio nets for sharing information and keeping a check
  • Low ongoing running costs
  • GMDSS (Global Maritime Distress and Safety System)
  • Email and weather data files at a low cost

Disadvantages

  • The HF radios are expensive
  • Complex to install
  • Email transmission relies on connection to shore stations
  • Data transmission speeds can be slow
  • Simplex transmission slows downloads
  • High amp hours
  • Not portable - cannot be transferred into a liferaft
  • Considerable training is required to use it effectively
  • Many countries are reducing their HF services
  • HAM radio requires a license
  • Transmission depends on radio propagation

Inmarsat satellite connection

Advantages

  • GMDSS and IMO-approved satellite networks used by commercial shipping
  • Easy to install
  • Make/send and receive phone calls, sms, weather downloads and email
  • Almost global coverage apart from poles (the network comprises three geostationary satellites located along the equator)
  • Sat C can send a distress message to all vessels in your ocean area at the touch of a button
  • Sat C safety and weather information is broadcasted free of charge
  • Less variability of the signal strength and dropped calls than Iridium
  • No subject to propagation problems
  • Satphones are portable - can be taken off the boat in a waterproof case if abandoning ship
  • Duplex transmission speeds up downloads (faster than SSB)
  • No compulsory training/license/certification is required

Disadvantages

  • Sat C is a very old system with limited capabilities for anything beyond basic text messages
  • Fleet broadband minimum data subscription is expensive (starting at around $120 per month for 10 mb)
  • Data usage is more expensive than Iridium
  • Fewer satellites are available to get a clear line of sight (coverage is provided by just 3 satellites).
  • Inmarsat’s satellites orbit the Equator on geostationary orbit so the further you travel from the Equator, the more difficult it will become to achieve line of sight to the satellites. The coverage is reliable between 70 South and 70 North
  • Ongoing costs in the form of prepaid or pay-as-you-go airtime packages for calls and data
  • High call charges for people calling you, particularly via cellular phones

Iridium satellite

One of the best solution for ocean going pleasure vessels.

Advantages

  • Cheaper subscriptions (plans) than Inmarsat
  • Global coverage including poles (network made up of a constellation of 66 satellites)
  • Easy to install and use, especially with Iridium Go
  • Make/send and receive phone calls, sms, weather downloads and email
  • Flexible plans: can change and cancel plan anytime
  • Programmable SOS button to notify specified contacts and connect to GEOS Emergency Response Service for free
  • No subject to propagation problems
  • Full range of communication capabilities
  • Staphones/Iridium Go are portable - can be taken off the boat in a waterproof case if abandoning ship
  • No compulsory training/license/certification is required

Disadvantages

  • Not recognised within the GMDSS system yet, although calls can be made to MRCCs (Maritime Rescue Coordination Centres)
  • No means for automatically receiving navigation and weather warnings
  • No automatic distress alert function
  • More variability of the signal strength than Inmarsat
  • Ongoing costs in the form of prepaid or pay-as-you-go airtime packages for calls and data
  • High call charges for people calling you, particularly via cellular phones
  • Cannot pause and un-pause a plan. After cancellation a new SIM card and activation fee is required

Probably the best option if you need fast internet and/or plan to work from your boat remotely.

Advantages

  • Full broadband data speeds of up to 50-250Mbps (thanks to using thousands of low orbiting, low latency satellites)
  • Monthly subscription are becoming attractive
  • Can pause and un-pause service at any time
  • Global maritime coverage

Disadvantages

  • Not as stable as Iridium or Inmarsat yet. Cannot really be transferred into a liferaft as it requires a dedicated antenna
  • Expensive hardware (antenna)
  • Requires Flat High Performance antenna installation on board
  • Not recognised within the GMDSS system
  • No means for automatically receiving navigation and weather warnings
  • No automatic distress alert function
  • Ongoing costs in the form of airtime packages
  • Only really for data but an app on a mobile phone (eg. WhatsApp) allows you to make and receive calls using your Starlink connection

If you opt for Starlink you will still likely need something like Iridium for emergencies as described here.

Iridium Go Satellite hotspot

The two main equipment options available for the Iridium network are Iridium satellite phone and Iridium GO!. For better speed choose Iridium GO! exec.

Iridium GO is essentially a modem that enables you to use your smartphone or tablet to make voice calls, share photos, access emails, SMS two-way, use GPS tracking and send out SOS alerts. You can connect to the device via Wi-Fi from your smartphone or tablet. It needs a paired mobile phone to make voice calls and only certain apps work with it.

The Iridium phone is generally more reliable than Iridium Go since you don’t need additional devices like a smartphone or tablet, but it’s more complex to use and more expensive. Therefore, Iridium Go is probably a better option for you. It is a more economical version of the Iridium’s handsets but without the numeric keypad.

What you need to purchase

  • Iridium GO device (one-time cost of $900)
  • Airtime for a prepaid SIM or a subscription (plan) to provide voice and data minutes (cost starts from $50 per month)
  • SIM card (cost $10)
  • Weather forecasting app that can work with satellite connection (e.g. predictwind standard, cost $249 per year)
  • (Optional) Iridium Go external antenna (one-time cost of $450). The reception is much better with the external antenna, but you can go by without (just make sure to bring the device outside the cabin so that the sky view is unobstructed)

How the subscription (plan) works

There are several subscription providers available. I’ve been very happy with the Predictwind and can recommend it. Predictwind is a one-stop shop for everything Iridium Go and weather forecasting.

Choosing the suitable subscription and activating the SIM card are done once you have the SIM card in hand. In the first month after activation billing is pro-rated, e.g. if activating on the 15th of the month you will only be charged 50% of the monthly fee. For subsequent months the billing period begins from the 1st of the month to the final day of the calendar month.

Predictwind offers 3 data/airtime plans for the Iridium GO:

  • Basic - recommended as a holding or set up plan only (5 internet data minutes only, the rest pay per use)
  • Plus - 150 minutes of voice calling and internet data, and unlimited SMS
  • Unlimited - 150 minutes of voice calling, unlimited internet data and unlimited SMS

Data speeds are limited to 2.4kBps hence downloading a weather forecast typically takes around 15 minutes. Therefore, the Unlimited plan is the best option most of the time. The Plus plan is only suitable for short trips (up to 6 days a month) as you will probably want to download the weather forecast twice a day (in the morning and evening). Sending and receiving emails would consume additional minutes.

You can change your plan anytime during the month, the change will take effect immediately. You will be charged any overages that are due on the existing plan at the end of the month. You can only have one plan change per month. Plans can be cancelled at any stage during the month, the cancellation will happen immediately. But you cannot cancel the plan in the same month that you activate it.

If your trips are many months apart, the cheapest strategy would be to cancel your plan in between the trips and activate it again when you need it. This requires buying and activating a new SIM card, but this is likely to be much cheaper than keeping the plans running. If your trips are just a few months apart a better option might be to change the plan to Basic so that you hold your SIM card while incurring fewer charges when you don’t need your Iridium Go.

What you need to install

The Iridium Go device act as an internet router / modem. You will need to install some apps on your smartphone / tablet / laptop:

  1. Iridium Go App for making phone calls and sending / receiving SMS
  2. Iridium Mail App for sending / receiving email
  3. PredictWind Offshore App for downloading weather forecasts. You will need to buy a Standard license to be able to use it with a satellite connection

Setting up and Testing

Once you buy the Iridium Go device & SIM card, and install the required apps, follow the below steps:

  1. Active SIM card and choose the subscription (eg. predictwind). You will need the SIM card number printed on the card, the IMEI number printed on the box (also to be found under the battery), your credit card and your billing address. You will receive an email with the GO phone number.
  2. Insert the SIM card into the Iridium Go device.
  3. Lift the antenna of the Iridium Go device to start it. Once the device boots, you can switch it to the Data (Internet) Call mode, by clicking the Internet Call button. You need this if you want to download weather forecasts and send / receive emails. The data minutes are counted from the moment the internet call is enabled.
  4. Make sure that you have 5 bars of signal strength prior to use. If you don’t use an external antenna you will have to bring your device outside. Without full signal strength, the data rate will drop dramatically, i.e. 5 bars => full speed, 4 bars => 50% speed, 3 bars => 10% speed, 2 bars and below => usually the connection drops.
  5. Connect to the Iridium Go Wi-Fi on your smartphone. The Iridium Go act as a router, and it should be available as a Wi-Fi connection when it boots.
  6. Log in to the Iridium Go App (use the default ‘guest’ username and password).
  7. For testing, make a phone call to someone in your contact list. The receiving end will incur local phone call charges (no additional satellite charges apply).
  8. Set up the SOS button. Iridium GO! Offers a programmable SOS button that can be configured to notify specified contacts in the case of an emergency. Once configured, an SOS can be initiated either from the Iridium GO! Device or the application. To support the SOS feature, Iridium has contracted with GEOS an emergency response coordination service at no additional charge.
  9. Program additional numbers in your phone: your contact ashore, the nearest Maritime Rescue Co-ordination Centres, radio-medical services, e.g. free International Radio Medical Center (CIRM) which has doctors available 24/7.
  10. For testing, send an SMS from your phone to someone in your contact list.
  11. For testing, send an SMS to Iridium Go via the Iridium Messaging. Just type the Iridium Go SIM card number & message and click send. While it is possible to send SMS and make phone calls to the Iridium GO directly, it is expensive and usually has to be enabled by the mobile provider. A more economical option, for people to contact you is to use the Iridium Messaging or email.
  12. Register for an Iridium email account. Your email address will be: “@myiridium.net”
  13. For testing, send an email from the Iridium Mail App to your private email address.
  14. For testing, send an email from your private email address to your Iridium email address.

Additional Tutorials

Fair Winds and Following Seas!