Telltale

sailing · sailing knowledge

Passage planning with wind, waves and tidal currents

Plan for the weather at each point when you get there, and know when the current turns at the narrow bits.

By Telltale Team · Reviewed

Before you go

  1. Estimate when you reach each exposed stretch and each pass, at your normal speed and 1 kn slower.
  2. Read the forecast for each of those times, not just for departure. Conditions
  3. Look up slack at every pass on the route and fit the plan around it. The passes
  4. Check the stations along the route the morning you leave.
  5. Agree a turn-back point and a bolt hole with the crew.

Break the trip into legs and times

Each leg meets the forecast for a different hour.

A 30 NM passage at 6 kn takes five hours; at 5 kn it takes six. That hour moves your arrival into a later forecast window, and the open-water leg into a different part of the day. A router does this sum for every departure time at once.

A Telltale passage plan from Eagle Harbour to Plumper Cove: departures that keep every rule and greyed ones, leave 12:55 and arrive 15:16, the arrival spread across four model runs, and the legs.
In TelltaleWhen she can leave. Plan a passage from Conditions and Telltale sails every departure in your window through each forecast model and the currents, greys the ones that break a rule and says why, and gives the arrival time across the models. Weather routing

Read three views

The marine forecast, the model wind, and the stations.

The official marine forecast and warnings cover the area. Model guidance gives detail by hour and place. Stations tell you what is happening now.

  • A sheltered station can read light while the open water is blowing.
  • A reading more than an hour old is history, not now.
  • Differences between stations are clues; check their exposure first.

References 1 2

Time the passes

At a narrow pass, the current can be faster than you.

Use CHS predictions for the pass itself. Aim to arrive in a slack window or with a fair current, and know when the next maximum arrives in case you are late.

Slack windows at First Narrows, 6 October 2026CHS predictions for First Narrows on 6 October 2026: max flood 00:09 0.8 kn, slack 01:59, max ebb 06:08 3.3 kn, slack 09:29, max flood 13:04 3.9 kn, slack 16:44, max ebb 19:41 2.7 kn, slack 22:59.flood ↑ebb ↓01:5909:2916:4422:593.3 kn3.9 kn2.7 kn
Slack windows at First Narrows, 6 October 2026. Real CHS predictions for one day. Plan the transit for a slack window, and know when the next maximum arrives.
Telltale Conditions in Current mode at First Narrows: five passes with the current rate now, the next slack and the next maximum for each.
In TelltaleCurrent at the passes, with the next slack. Switch Conditions to Current for the CHS prediction at First Narrows, Dodd Narrows, Gabriola, Porlier and Active Pass: the rate now, the next slack and the next maximum. Open the passes

References 4 3

Wind against current

The same wind builds a much steeper sea when it blows against the current.

Check where on the route the current will oppose the forecast wind, and at what time. A 15 kn westerly against a strong ebb is a different sea from 15 kn with it, so read the current for a pass or a river mouth at the same hour as the wind.

Update underway

Compare progress with the plan at each leg.

If you are an hour behind, the arrival forecast has changed: read it again. Make the turn-back decision at the point you agreed, not halfway across.

Telltale Conditions off English Bay: four model values side by side with the best one marked, the spread between them, live readings from nearby stations, and First Narrows with its next slack.
In TelltaleEvery model and the stations near one spot. Tap the water and Conditions shows each model’s wind for that spot, how far they disagree, the fresh station readings within 20 km and how the current is running. Open Conditions
Sources and review

Official references checked on 2026-10-11. Product details and schedules change; the provider’s page is the current word.

Take it to the water

Check the stations before you leave, then record the sail for the debrief.

Open ConditionsRecord a sail