Masters Said the Link Was Too Slow. Weathernews Added an Offline Mode.

We keep writing that AI on a ship is only as good as the link. This week a large weather company showed what happens when you ask masters.

What masters reported. Weathernews, the Japanese weather company, tested its navigation support tool for masters, SeaNavigator for Master, between February and April 2026. The masters reported weak satellite coverage in parts of the Southern Hemisphere. They reported delays of more than 1,000 milliseconds, which means every click waits over a second for an answer. Routes failed to load. And in some coastal waters satellite use was restricted.

What Weathernews did. It launched an offline mode. A helper program downloads the weather for a chosen sea area, with a forecast of about 7 to 14 days, and keeps it on the ship's computer. Downloads can be planned up to four times a day, for the hours when the link is good. When the link drops, the forecast and the planned route stay on screen. The program can be installed from a shore connection or from a USB stick. It is available now.

The limit, and it is the point of this story. Two things still need a live link: testing a new route, and the tool's AI agent. So the map and the forecast work offline. The AI does not.

Why this is worth reading. It is a small product update. But it is one of the few times a supplier says in public what crews told it and what it changed. And it shows where the industry really is. The data can now live on board. The AI still lives ashore. Last week a bank showed that AI can run on a company's own computers. Nobody has yet shown that for a ship.

What to ask any supplier of AI for ships. What works when the link is down for a day? What works when the link is slow? Which parts need the AI ashore, and what does the master see when it cannot answer? Ask them to show you with the cable pulled out. [Digital Ship · Smart Maritime Network · AiatSea, 8 November]

This story is part of the Maritime AI Digest of 15 November 2026.