I grew up learning to sail in Ottawa, where “current” was what happened on flowing river (mostly when canoeing), and “tide” was what swallowed up the beach slowly on those rare family vacations to the ocean. Sailing on Lac Deschene on the Ottawa River, there really wasn’t much current and certainly no tide, so my sailing education didn’t really include either. The last 5 years of sailing on the West Coast has taught me a lot about both.
We left Rebecca Spit on Quadra Island on Monday morning, headed up toward the maze of islands and the Johnstone Strait, which separate the top end of Vancouver Island from the mainland. Glenda had been working on a passage plan for a couple of days, because this is an area dominated by tide and current. As the tide rises in the Pacific Northwest, it rushes in the Juan de Fuca Strait below Vancouver Island and the Johnstone Strait above Vancouver Island to fill (or drain) the Salish Sea. With the tides running at upwards of 5 metres, it’s a huge volume of water that drives strong currents through the narrows in the islands, both on the flood and ebb tides. Many of the tidal rapids run at over 9 knots. We sail at an average of a little over 5 knots, and max speed under motor is just over 7 knots. So, show up at the wrong time and these rapids are basically impassable. Even once through the rapids, the current in many channels flows at 4 knots, so we can make a lot more progress travelling with the current than against it. This is not the Ottawa River.
An example of one this morning’s rapids… Note the peak currents and how short the time is at “Slack Tide” or zero current.
Hence the passage planning… Picking our departure times, anchorages, and routes through the islands so we hit rapids when the current is slack, and travel with the tide in our favour. We also need to pay attention to the weather, as the winds on Johnstone Strait build during the day and 40 knots (74km/h) of wind is not uncommon.
Passing through Surge Narrows to Octopus Islands Provincial Park on Monday was pretty simple, with slack tide around noon and a small procession of boats going through at the same time as we were. Tuesday morning, however, the alarm went off early (along with the coffee maker), and we were off to catch our first rapids by 7:20 am, picking up the flood tide thereafter to carry us on a boisterous sail along the Johnstone Strait with 20 knot winds at times and 4 knots of current in our favour.
Tonight we are anchored at Helmcken Island about halfway along the Johnstone Strait. Tomorrow will be another early start to catch the ebb tide again, heading for an anchorage across from Robson Bight Ecological Reserve, and hopefully some orca sightings.