Measure what's actually happening
at your boat — not a forecast.
The same technique professional navigators have used for decades — now on your iPhone.
Toss a fender, bottle, or any floating marker. Tap Mark Start — Drift GPS-locks your position with sub-meter precision.
Let the current carry your marker. Thirty seconds is a solid racing read. A minute is great. Two minutes is best.
Walk to your marker, tap Mark End. Direction in degrees true. Speed in knots. Instantly. No guesswork.
Weather apps and chart plotters show modeled current from databases. Drift measures what's actually happening at your exact GPS position, right now, at this tidal state.
Temporal windowing and outlier filtering give you a stable fix — even when the sky is partially blocked.
High-contrast UI, 80px touch targets, and large type — designed for gloves, spray, and bright sun.
GPS only. No cell service, no WiFi, no data plan. Works on any water on earth.
5 readings per session. Drift tracks whether the current is growing or rotating — so you know what's coming.
The precise numbers your tactician uses — bearing in degrees true and speed in knots. Plus the 16-point cardinal label your brain can use instantly.
One purchase. No subscription. No ads. No account required. All future updates included.
Tidal models are accurate to within a mile. Your race mark is 200 meters away. That gap is the difference between port and starboard layline.
LAST UPDATED · MARCH 2026
Drift is developed and published by Sorensen on Sound LLC. This policy explains what data the app accesses, how it is used, and your rights.
Drift collects no personal information. No account required. No name, email, or identifying data collected. The app communicates with no external server.
Drift uses your device GPS to measure water current. Access is "When In Use" only — only while the app is actively open. Location data:
Up to 5 readings per day are stored locally using standard iOS storage. This data never leaves your device and clears automatically each day.
Drift contains no analytics SDKs, no tracking, no advertising, and no third-party code that collects data. The app does not use Apple's IDFA.
Drift collects no data from any user. Rated 4+ on the App Store.
If this policy changes materially, the date above will be updated. Continued use constitutes acceptance.
Sorensen on Sound LLC
support@driftapp.ioDRIFT · VERSION 1.0 · iOS
We want Drift to work perfectly on the water. Every message gets a reply — usually within 24 hours.
Stand outside with a clear view of the sky for 30–60 seconds. Check Settings → Privacy → Location Services → Drift and confirm "While Using" is enabled.
You must physically walk to your marker to tap Mark End. Drift measures GPS displacement between two points — watching from shore reads as zero movement.
30 seconds unlocks GOOD — solid for racing. 60 seconds is GREAT. 90 seconds is BEST. In a race, tap Mark End anytime after GOOD appears.
With an Excellent or Good GPS badge, readings are accurate to within a few hundredths of a knot and a few degrees. The badge shows live accuracy.
Yes, completely. Drift uses only your device GPS — no cell signal, no WiFi, no data plan needed. Works anywhere in the world.
Tap the chart icon in the top right of the home screen to view today's readings and trend analysis. Up to 5 readings are stored per day.
Email us directly — we read every message.
support@driftapp.ioPlease include your iOS version and what happened.