iStreams gives you instant access to the Portland tidal stream atlas, aligned to the current time using High Water at Devonport — even when you're offline.

Whether you're sailing, navigating coastal waters, or passage planning, iStreams helps you understand tidal flow quickly and accurately.

🌊 Key Features
Real-time tidal stream charts
Automatically displays the correct hourly chart based on the nearest Devonport High Water time.
Fully offline functionality (forecast link requires a connection)
No signal? No problem. All charts and tools work without internet access.
Automatic chart updates
As time progresses, the app switches to the next valid tidal period.
Simple swipe navigation controls
Swipe forward and backward through tidal hours with ease.
Pinch to zoom and drag to explore details.
Toggle between Local Time and UTC.
Show boat position on chart.

🧭 Navigation Tools
Interpolated Rate Calculator
* Instantly calculate stream rate between neaps and springs.
Tidal Set Tool (In-App Purchase)
* Measure the true direction of tidal stream arrows with precision.
Course to Steer (CTS) (In-App Purchase)
* Calculate the correct heading to maintain your intended course.

⚓ How It Works
iStreams automatically selects the nearest High Water at Devonport and displays the corresponding tidal stream chart.

Want to plan ahead or review earlier conditions? Simply swipe forward or backward through the tidal hours to view past or future data.

✅ Why Choose iStreams?
Designed for sailors, navigators, and coastal users
Fast, clear, and easy-to-use interface
Accurate tidal data when you need it most