LUBBER LINE

Marine compass with course-steer, true north and speed in knots — fully offline.

Contact us

Questions, feedback or a problem to report? We read every message.

crews-twelves.4d@icloud.com

Frequently asked questions

The compass points the wrong way, or jumps around.
Phone compasses are sensitive to magnetic interference: cases with magnets, magnetic car mounts, and nearby metal or electronics. Move away from the source and the heading will settle. If iOS suggests calibrating, follow the on-screen motion.
Why does it show "M" instead of "T" next to my heading?
"M" means the app is reading magnetic north because there is no GPS fix yet. It needs a view of the sky; "T" (true north, corrected for declination) appears automatically once a fix arrives. Nothing is wrong.
My coordinates show "—" and speed shows "—".
Position, true-north correction and speed all come from GPS hardware. Check that Location Services are enabled for Lubber Line (Settings > Privacy & Security > Location Services) and that you have a view of the sky.
The compass froze and a banner says it needs Location Services.
On iOS, even the magnetic heading sensor requires Location Services to be on. Tap "Open Settings" in the banner, enable Location Services, and return to the app — the compass recovers by itself, no restart needed.
Speed sits at 0.0 kn for a moment after I stop.
By design. GPS speed fades over a few seconds, so Lubber Line uses the motion sensor to pin speed to an honest 0.0 the moment you stop (it never engages at cruising speed). If it lingers, a small movement will release it.
How do I set or change my course?
Point at your desired heading and tap the anchor ⚓ — the course locks and a cyan arc shows your delta. Tap the anchor again to release. Trim with the − / + buttons: tap for ±1°, hold for ±10° (repeats while held). Your course is remembered across restarts.
Does Lubber Line collect my data?
No. No accounts, no analytics, no tracking, no ads — your position never leaves the device. See our Privacy Policy.
Can I use it for real navigation?
Lubber Line is a consumer compass. It is not a substitute for certified marine or aviation navigation equipment.

About

Lubber Line — a marine-style compass for iOS.

True-north correction from the World Magnetic Model, course-steer with a glowing delta arc, speed over ground in knots, and a butter-smooth upright rose. Heading comes from on-device sensors; position from on-device GPS.