What it is
Authoritative tide and tidal‑current station data, from CHS (Canada) and NOAA (US), integrated directly into the chart. Review current speed and direction, tide height, slack‑water periods, turning times, and upcoming events — plus up to 30 days of tide predictions and the moon phase. It's especially valuable around harbours, channels, narrows, and tidal passages.
Want to check tides, currents, and nearby station observations while planning a real trip?
The 30-day free trial includes the complete experience, so you can evaluate SeaVectors with your own routes and equipment before deciding whether to subscribe.
- Download SeaVectors on the App Store
- Get SeaVectors on Google Play
- Not ready to install? Open the lightweight web chart for a quick preview.
Why it matters on the water
Tides decide whether you can cross a bar, clear a bridge, or find water in a thin anchorage. Currents decide whether a passage through a narrows is a fast, comfortable ride or a slog against a foul stream — or, wind‑against‑tide, a genuinely dangerous sea. Having both, from official hydrographic sources, right on the chart means you plan depth and timing without leaving the app.
Slack water is the brief period when a tidal current is near zero, between flood and ebb — the calm window to transit a narrows. Set is the direction the current flows toward; drift/speed is how fast. MLLW (Mean Lower Low Water) is the chart datum tide heights are referenced to.
Stations on the chart
As you zoom in, SeaVectors shows the tide and current stations in view. Zoom in further and the markers go live, drawing each station's real now value:
- Current stations become a set arrow — pointing the way the current is flowing, colour‑coded by speed band.
- Tide stations become a level gauge showing the state of the tide.
Tap a live station marker to open the panel at that station, with its full predictions. The station catalogue (CHS & NOAA) syncs automatically, and stations shown at detailed zoom quietly download about two weeks of forecast so they're ready offline (see module 15 to pre‑save a whole area before a trip).
The station panel
Tides
Open the Tides tab. A summary bar shows the now / next at a glance — the next high or low and its time — above a curve of the day's highs and lows.
1. SeaVectors picks the nearest/most relevant tide station.
2. Swipe day by day — up to 30 days — to read highs, lows, and their times.
3. Heights are referenced to MLLW; the moon phase is shown for context (spring tides near new/full moon, neaps near the quarters).
Currents
Open the Currents tab. The summary bar shows the current state — Slack, Flooding, or Ebbing — and the next event ("Turning tide"), for example slack 14:20–14:45, turning point around 14:32.
1. SeaVectors finds the nearest current station.
2. Read the speed and set now and across the day.
3. See slack‑water windows, maximum flood/ebb turning times, and upcoming events so you can time a transit.
Where no current station is in range, SeaVectors falls back to a modeled ocean current (Open‑Meteo) so you still get set and speed — the panel tells you which source you're seeing.
How to use it (a narrows, start to finish)
- Zoom in on the passage; the current station marker goes live — glance at the set arrow's direction and colour for the state now.
- Tap it to open the Currents tab; read the next slack window and turning time.
- Plan your transit for slack or a fair (with‑you) current; avoid max flood/ebb against you, especially wind‑against‑tide.
- Switch to Tides to confirm you'll have enough water at your arrival time (add predicted tide to the charted depth; keep your Safety‑depth margin — module 02).
Tips
- Time narrows and tidal passes for slack or a fair current. The turning times are the two numbers to write down.
- Around harbours and channels, keep an eye on the set arrow colour as you zoom — it's the fastest read of "how hard is it running right now."
- Plan bar crossings near high water on a rising tide, so you float free if you touch.
- Watch the moon phase: spring tides (new/full moon) give the biggest range and the strongest currents.
- For a trip into thin coverage, pre‑save the area's forecasts before you leave (module 15).
Troubleshooting
- No tide/current data, or "Finding nearest station…" stalls → Needs a connection to fetch predictions the first time; connect and reopen. Saved stations stay available offline.
- Station seems far away → SeaVectors uses the most relevant available station; where stations are sparse, the nearest may be some distance off — interpret accordingly.
- Currents show "No station in range" → You're seeing (or waiting on) the modeled ocean‑current fallback; zoom to an area with a charted current station for station‑grade data.
- Heights/times don't match another source → Confirm the same datum (MLLW) and time zone.
Note
Tide and current predictions are forecasts from official sources; actual conditions vary with weather (wind, pressure). Around narrows and passages, allow margin and keep a lookout.