Communications at Sea
When you're 500 miles from the nearest cell tower, how you communicate determines whether you get weather, whether you stay connected, and whether help can find you.
VHF Radio — Beyond Emergencies
VHF radio is covered in depth in the Emergency section for distress calling. Here we focus on VHF as a routine communication tool for voyage planning and passage management.
Harbour operations: Most harbours, marinas, and port authorities monitor VHF Channel 16 and have a working channel (often 09, 12, or 14 — listed in pilot books). Call ahead to request a berth, report your ETA, or get approach instructions. In busy commercial ports, VHF communication with port control is essential — they need to know you're coming and they'll tell you when it's safe to enter.
Bridge-to-bridge: When encountering commercial shipping in restricted waters, VHF Channel 13 (or 16 for initial contact) allows you to communicate directly with a ship's bridge. 'Motor vessel on my starboard bow, this is sailing vessel [name], I am crossing the channel northbound, request you confirm your intentions.' Clear, concise, professional. Don't rely on it — they may not answer — but it's a valuable tool in congested waters.
Weather broadcasts: Coast guard stations broadcast weather forecasts on scheduled times on specific VHF channels (e.g., NOAA Weather Radio in the US on dedicated WX channels). Know the schedule and the channel for your region. These are the most accessible weather updates available — no subscription, no equipment beyond the VHF you already have.
Limitations: VHF is line-of-sight — range is typically 20–30 miles from a masthead antenna to a shore station, less to another yacht. Once you're more than 30 miles offshore, VHF is limited to ship-to-ship communication with vessels within range. For offshore passages, you need SSB or satellite communications.
Program your VHF with the working channels for every port on your route before departure. Scrolling through all 80+ channels looking for the right one while approaching a busy harbour is inefficient. Most modern VHFs allow you to name stored channels — label them by port name.
What is the practical range of VHF radio from a yacht?
SSB/HF Radio
SSB (Single Sideband) radio operates on HF (High Frequency) bands and provides long-range voice communication — hundreds to thousands of miles. Before satellite phones, SSB was the only way to communicate from mid-ocean. It remains valuable and widely used in the cruising community.
Range and propagation: SSB signals bounce off the ionosphere, giving them ranges of 500–3,000+ miles depending on frequency, time of day, and atmospheric conditions. Lower frequencies (4 MHz band) work better at night; higher frequencies (8–12 MHz) work better during the day. This propagation behavior means SSB can reach further than VHF but is less reliable — atmospheric conditions affect signal quality.
Cruiser nets: The most valuable use of SSB for cruisers is the daily radio net. Networks like the Pacific Seafarer's Net, Caribbean Safety and Security Net, and various regional nets broadcast daily on scheduled frequencies. Boats check in with their position and weather observations. The net controller relays weather forecasts, emergency information, and messages. These nets are a social lifeline, a weather service, and a safety network rolled into one.
Email via SSB: Services like SailMail and Winlink allow email and weather file (GRIB) downloads via SSB radio and a modem (Pactor or VARA). The data rate is slow (a GRIB file download may take 10–15 minutes), but it works anywhere in the world without a satellite subscription. For cruisers on a budget, SSB email replaces satellite communication at a fraction of the cost.
Licensing: SSB radio operation requires a licence in most countries — a Long Range Certificate or equivalent. The licensing process includes understanding frequency selection, call procedures, and regulations. Some countries also require the radio itself to be licenced (ship station licence).
Post the cruiser net schedule (frequency, time, net name) on the bulkhead next to the SSB radio. Tune in even if you don't check in — listening to weather reports and position reports from other boats provides situational awareness that satellite data alone cannot match.
Why do SSB frequencies need to change between day and night?
Satellite Communications
Satellite phones and communicators have transformed offshore communication. What required an SSB radio, a licence, and skill in 2000 now requires a handheld device and a subscription.
Satellite phones (Iridium): Iridium is the only satellite network with true global coverage (pole to pole). An Iridium satellite phone provides voice calls and basic data from anywhere on Earth. Call quality is adequate, not great. Data rates are slow (2.4 kbps). Airtime is expensive ($1–2 per minute for voice). For weather downloads, email, and daily check-ins, an Iridium phone is sufficient.
Iridium GO and similar devices: The Iridium GO creates a small WiFi hotspot using the Iridium network, allowing a phone or tablet to send/receive email, download compressed weather data, and post position reports. It's more versatile than a basic satellite phone and allows the crew to use familiar devices (phone apps) for communication.
Satellite messengers (Garmin inReach, SPOT): These smaller devices send preset messages, GPS position reports, and limited custom text messages via satellite. The Garmin inReach also provides two-way text messaging and SOS functionality. For many cruisers, an inReach provides adequate communication — daily position reports to family, weather forecasts via the Garmin app, and an SOS button for emergencies — at a lower cost than an Iridium phone.
Starlink: Starlink marine terminals provide high-speed internet at sea — speeds comparable to home broadband. This is a game-changer for communication (video calls, full email, real-time weather) but requires a significant hardware investment and monthly subscription. Starlink coverage is expanding but not yet global, with gaps in some ocean regions.
For a first offshore passage, carry at minimum a Garmin inReach or similar satellite messenger. Daily position reports to a shore contact, two-way text messaging for weather updates, and an SOS button provide basic safety communication at a fraction of the cost of a satellite phone.
Which satellite network provides true global coverage including the poles?
Position Reporting and Check-In Schedules
A position reporting system ensures that someone always knows where you are. On a coastal passage, a phone call at departure and arrival may be sufficient. On an offshore passage, daily (or more frequent) position reports are essential.
Automated tracking: Devices like the Garmin inReach, YB Tracker, and similar units send GPS position reports at preset intervals (every 1, 2, 4, or 6 hours) to a web page that family and shore contacts can view. This is the most reliable system — it works automatically, requires no crew action, and provides a continuous track. If the track stops updating, the shore contact knows something may be wrong.
Manual check-ins: A daily satellite phone call, SSB net check-in, or text message to a shore contact provides position and status. Agree on a specific time and method. If you miss a check-in, the shore contact should attempt to reach you by other means before alerting authorities — a missed check-in is often a communication failure, not an emergency.
Cruiser nets as reporting systems: Joining a cruiser SSB net provides daily position reporting to a net controller who maintains a log of all vessels' positions. If a boat misses multiple check-ins, the net controller can alert other boats in the area and coordinate with coast guard or rescue services. This informal network has initiated many searches and rescues.
Redundancy: No single communication system is perfectly reliable. Carry at least two independent means of position reporting — for example, a Garmin inReach (satellite) and an SSB radio (HF). If one fails, the other continues. The shore contact should know which systems you're carrying and which to rely on as primary and backup.
Give your shore contact a written communication plan: 'We will report position daily at 1800 UTC via inReach. If no report is received for 48 hours, call [satellite phone number]. If no answer for a further 24 hours, contact [coast guard number] with our last known position from the tracking page.' This script prevents both panic (one missed check-in) and complacency (three missed check-ins).
Why is automated satellite tracking preferred over manual check-ins?
Summary
VHF radio is line-of-sight (20–30 miles) — essential for harbour operations, ship-to-ship, and coast guard weather broadcasts, but useless beyond 30 miles offshore.
SSB radio provides 500–3,000+ mile range with voice, email (SailMail/Winlink), and weather data — plus daily cruiser nets that provide community and safety.
Iridium is the only satellite phone network with true global coverage. Garmin inReach provides affordable satellite messaging and tracking.
Carry at least two independent communication systems for offshore passages — redundancy ensures position reporting continues if one system fails.
Give the shore contact a written escalation plan: what to do if check-ins are missed, with specific timelines and contact numbers.
Key Terms
- SSB (Single Sideband)
- HF radio providing long-range voice communication (500–3,000+ miles) by bouncing signals off the ionosphere
- Cruiser net
- A daily scheduled SSB radio broadcast where boats check in with positions and weather — providing community, weather data, and safety oversight
- SailMail / Winlink
- Services that provide email and weather file downloads via SSB radio and a modem — slow but available anywhere in the world
- Iridium
- A satellite phone network with 66 LEO satellites providing global coverage pole-to-pole — the standard for offshore voice communication
- Satellite messenger
- A compact device (e.g., Garmin inReach) that sends position reports, text messages, and SOS alerts via satellite at lower cost than a satellite phone
Communications at Sea Quiz
What limits VHF radio range?
What is the primary advantage of SSB over satellite phones for cruising sailors?
Why should you carry two independent communication systems offshore?
What should a shore contact do if one daily check-in is missed?
What does a Garmin inReach provide that a basic EPIRB does not?
References & Resources
Related Links
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SailMail Association
Email and weather data via SSB radio — the cruiser's long-range email service
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Garmin inReach — Satellite Communicators
Satellite messaging and tracking devices for offshore communication