Ship-to-Shore Data: Connectivity Options for Fishing Vessels

Connectivity options at a glance

Fishing vessels send data ashore over four kinds of links: mobile networks (4G/5G) near the coast, L-band satellite services with global coverage, broadband VSAT via geostationary satellites, and low Earth orbit (LEO) satellite broadband, with store-and-forward at port as the fallback. For weighing and catch data the volume is so small that the choice is driven by coverage, reliability and cost rather than by bandwidth.

Mobile networks near the coast

4G and 5G are the cheapest and fastest option when the vessel is within range of shore masts, which in practice means coastal and inshore fisheries.

Range at sea is highly variable. It depends on mast height and siting, the frequency band (lower bands such as 700–800 MHz travel further), the vessel's antenna height and gain, and sea state. Dedicated maritime deployments can extend coverage considerably: the GSMA reports a 5G deployment for fishing vessels in Guangdong, China, that provides downlink speeds of 400 Mbps up to 30 km offshore and 60 Mbps up to 61 km from the coast (GSMA 5G Transformation Hub). Such figures describe one engineered network, not typical coverage elsewhere. For planning, assume mobile data may be available near the coast and in port, and design everything else to tolerate its absence.

Satellite options: L-band, GEO VSAT and LEO

Satellite links cover the vessel beyond mobile range, and they differ mainly in frequency band, orbit, antenna and cost per megabyte.

L-band services

L-band (1–2 GHz) provides reliable, low-data-rate communications with excellent resistance to weather, according to the European Space Agency. Terminals and antennas are compact. As an example of capacity, Iridium Certus 700 is specified at up to 704 kbps down and 352 kbps up (Iridium). That is far more than weighing data needs, which makes L-band a common backup link and the primary link for smaller vessels.

GEO VSAT

Very small aperture terminals (VSAT) on Ku-band (12–18 GHz) and Ka-band (26–40 GHz) offer wider bandwidth but are more susceptible to signal degradation from rain fade (ESA). Geostationary satellites sit at an altitude of 35,786 km. A signal that travels up to the satellite and down again covers at least 71,572 km, which at the speed of light (about 299,792 km/s) takes about 239 ms. A request and its response therefore take at least about 480 ms before any processing or terrestrial routing. Maritime VSAT needs a stabilised antenna that keeps pointing at the satellite as the vessel rolls and pitches.

LEO broadband

Low Earth orbit is below 2,000 km altitude (ESA). The shorter distance cuts the propagation delay of one up-and-down hop to about 13 ms or less from altitude alone, so interactive use feels similar to terrestrial broadband. LEO constellations require antennas that track fast-moving satellites, often electronically steered flat panels. Coverage, regulatory authorisation in particular waters and commercial maritime terms vary by provider and region, so check them for the actual fishing grounds.

How much bandwidth weighing data needs

Weighing data needs very little bandwidth: a full day of box weights for a busy vessel amounts to a few megabytes, which even a narrowband satellite link can send in minutes.

A weighing record in JSON with ID, timestamp, scale, preset, weight, unit, stability and lot is roughly 250 bytes. The table shows worked estimates based on that assumption.

Two practical conclusions follow. First, protocol overhead can exceed the data itself if each record is sent as a separate HTTP request with headers and a new encrypted session; batching records, keeping connections open or using a lightweight protocol such as MQTT matters more than link speed. Second, repetitive JSON compresses well, so compressing batches before transmission reduces airtime further. Live video, crew welfare traffic and software updates, not weighing data, determine the size of the link.

Store-and-forward: designing for lost connections

Store-and-forward means every record is stored on board first and transmitted when a link is available, so that no data is lost when coverage drops, the antenna is blocked or airtime is switched off.

1. Write locally first. The scale or vessel system commits each record to local storage before any transmission.
2. Give every record a unique ID. The shore system uses it to discard duplicates when a batch is retried.
3. Timestamp at the source. Use the time of weighing in UTC, not the time of arrival ashore.
4. Queue and acknowledge. Remove records from the send queue only after the shore side confirms receipt. MQTT defines QoS 1 (at least once) and QoS 2 (exactly once) delivery for this purpose (OASIS MQTT 5.0).
5. Prioritise. Send catch and lot records before bulk logs and diagnostics when capacity is limited.
6. Monitor the backlog. Show the number of unsent records on board, so the crew knows whether shore has current data.
7. Reconcile at port. Compare record counts on board and ashore at every port call and resend any gaps.

The same principles apply to reading data from the scale itself; see Integrating Scales with Your Software via an API and Weighing Data Logging at Sea.

Security on the link

Connecting a vessel network to the internet exposes onboard equipment, so weighing systems should sit behind the vessel's firewall and send data outwards over encrypted connections rather than accept inbound connections from the internet.

• Separate operational equipment such as scales and graders from crew and guest networks.
• Use encrypted transport (TLS or a VPN) for everything that leaves the vessel.
• Do not open inbound ports to scales; let an onboard gateway initiate connections to shore.
• Change default passwords and restrict who can issue commands or change presets.

The IMO has published guidelines on maritime cyber risk management that shipowners can use as a framework.

Choosing a setup

The right connectivity setup follows from where the vessel fishes, how quickly shore needs the data and what other traffic the link must carry.

How WPL approaches this

With the R50 Catch Label System, catch data can be sent ashore during the fishing trip. WeightControl logs every weighing automatically on the scale and makes records available as CSV, PDF and JSON through its API, so a vessel's own gateway or software can forward them over whichever link is on board. The choice of satellite or mobile service is independent of the scale. For the overall architecture from scale to shore, see the data integration hub; for processing workflows on board, the onboard processing hub.