app4sail vs Qastor

Nautical navigation app. uses free S57 vector charts Not everywhere in the world those maps are available and not all of the available maps are implemented at this moment. Instead you can use maps of the project 'Openstreetmap'

Qastor is a professional marine navigation and pilotage tool for maritime pilots. It combines high-precision positioning, live AIS traffic, and detailed nautical charts to support safe passage through harbors, ports, and confined waters. Built for the demands of real-time pilotage, Qastor gives you the situational awareness you need, accurate vessel position and heading, under-keel clearance, predicted tracks, and berth approach information, all on a portable display you can bring aboard any ship. Key features: Real-time AIS display of surrounding vessel traffic High-accuracy GPS positioning and heading Detailed nautical charts with depth and tidal information Docking and berth approach support Route and passage planning Works offline, independent of the ship's own systems Trusted by marine pilots for navigation in some of the world's busiest ports and waterways.