Percival
Offshore sailor voyage log
Free
Voyage logging and progress-tracking application for offshore sailors.
Marine Logbook
- Voyage & Fix Logging: Records position fixes, averaged speed, course, and timestamps over the course of a passage.
- Observations & Voice Notes: Allows sailors to record voice memos and text notes tied to specific GPS fixes.
- Noon-to-Noon Calculations: Calculates traditional passage-making metrics, such as 24-hour day runs (noon-to-noon) and daily distance made good.
Live Navigation Instruments
- Displays passage data including averaged Speed Over Ground (SOG), Course Over Ground (COG), Velocity Made Good / Velocity Made on Course (VMG/VMC), and range/bearing to destination.
- AIS & NMEA Integration: Ingests marine NMEA 0183 data streams and AIS vessel feeds (both local NMEA feeds and internet AIS) to monitor surrounding vessel traffic.
ETA windows
- Computes ETA estimates based on three velocity calculations.
Mapping
- Map Views & Waypoints: Plots the voyage track, note markers, and live positions over map layers (including NOAA charts and satellite tiles).
Sharing & Passage Data
- Standard & Native Exports: Exports trips in standard formats (.gpx, .csv) as well as native Percival voyage backup files (preserving tracks, notes, and voice clips) to share with other crew and sailors.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Redesigned UI for readability.
Wider range of import and export options.
Noon-to-noon logging.
AIS detail on Nav tab and Map tab.
NOAA charts.
The developer, SIMON DAVID ROBINSON, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- SIMON DAVID ROBINSON
- Size
- 27.4 MB
- Category
- Navigation
- Compatibility
Requires iOS 17.6 or later.
- iPhone
Requires iOS 17.6 or later. - iPad
Requires iPadOS 17.6 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Simon Robinson
