Oosterschelde · site 65a

Diving at Groene Boei

Current, slack and best dive times at Groene Boei

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Windows for the next 40 hours

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Current at Groene Boei

Over the next forty hours, a peak current of about 67 cm/s is expected here, around 12:30 tomorrow. The planner marks the moments when the current drops below 20 cm/s, the limit you chose above. That gives 6 windows in the forecast, averaging 1 h 5 min each.

Of the 34 sites in the Tide Planner, Groene Boei sits around the middle of the sites for current strength: the expected peak current here is well over 1.2× the average of the sites in the planner. That fits its position in the tidal system: in narrow channels and along the main flow the current can be stronger, while it's often weaker in side channels and behind dikes. Read how currents work in the Oosterschelde.

When is the best time to dive?

The best moment is the middle of the slack, when the current is at its lowest. How much time you get depends partly on the tidal range: around neap tide the differences stay smaller and the windows here are usually more generous, while around spring tide they can be shorter. Of the days in the forecast, Sat 24 Oct offers the most room: 08:20–09:50, 1 h 30 min. Click a window above for the details; the planner works out which dive fits.

Slack at Groene Boei

Slack is the moment the current changes direction, and the flow is briefly at its lowest around that point. In the Oosterschelde there are usually several slack moments per day, around high and low tide; the exact timing varies by location. At Groene Boei, not every slack gives you the same amount of time: the current picks up harder after one slack than after another.

The tidal cycle shifts by a good fifty minutes on average each day, but the slack time at this site isn't a simple copy of the day before. That's why this page shows no fixed time, but today's forecast.

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What matters at this site?

You get an average of 1 h 5 min per window here, enough for a normal dive, after which the current picks up again. The turning point falls within the window, not at the end.

This page covers current and tide. For local details such as entry, depth and parking, check other sources.

Dive plan

Plan your dive, share it with your buddies

Choose site, day and dive window, up to a year ahead. You get a shareable page for your group.

  • Email if the forecast changes
  • Exact times once the dive is within 40 hours
  • Only your email address needed
Beyond the forty hours

Monthly overview, up to a year ahead

Want to plan ahead? See per dive site which days are expected to be favourable for a dive around the slack.

This long-term forecast is based on the expected local current pattern and may therefore differ from traditional tide tables with high and low water (HW/LW).

Tap or click a time with + to turn it into a dive plan. You get a shareable page for your group, with a message if the exact forecast within 40 hours differs.

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Frequently asked questions

Do you need to wait for slack at Groene Boei?

Largely yes: the current here rises above 20 cm/s between slack periods.

Can I dive here outside of slack too?

Outside the window, the current here runs well above the 20 cm/s you chose.

Where does this current data come from?

From the live current forecast from Rijkswaterstaat, which projects forty hours ahead. Further ahead, the planner uses the recurring tidal pattern to project slacks and windows. That's suited to finding favourable days, but not to predicting exact current timing the way the 40-hour forecast does.

How many slacks are there per day?

Usually several, around high and low tide; the exact timing varies by location. The tidal cycle shifts by a good fifty minutes on average each day, but the slack time at a location is not a simple copy of the day before.

Can the actual current differ from the forecast?

Yes. A current forecast is a model calculation, not a measurement of conditions at that moment. Wind and air pressure can cause the actual current to differ from the forecast; always check the live forecast shortly before your dive.

What does the estimated temperature in the monthly overview mean?

Water temperature is measured at Marollegat, one measuring point for the whole Oosterschelde. For a day in the future, we take the temperature from about a year ago on the same calendar day, and add the difference between today's temperature and last year's on the current date. Right after the 40-hour forecast that difference counts in full; further ahead it fades out gradually, to zero after about a month. It's an estimate based on the seasonal pattern and the current deviation, not a prediction.

Can I plan a dive and share it with my group?

Yes. Click "Plan this dive" on a dive window, or a slack time in the monthly overview. You only enter your email address and get your own page to share with your group. It shows what was planned next to what is expected now, with an alternative time. Anyone following the dive gets a message when the forecast changes, and afterwards a short question about the visibility. No account needed, and email addresses are deleted 30 days after the dive.

Read more
All dive sites
Overview of the Oosterschelde and the Zijpe
Slack in the Oosterschelde
Why the current stalls and for how long
Tide Planner
Windows for all sites side by side
Tides in the Oosterschelde
How the tidal cycle works, and spring and neap tide
Current in the Oosterschelde
What causes the current and why it differs per site

Important

The tide and current forecast is a prediction and may differ from conditions on site. Wind, water level and other conditions can affect the current. Always check the conditions on site and take responsibility for your own dive and safety.

More about the data, sources and accuracy used can be found at About Duiken Centraal.