San Juan Islands Cruising Truths
Let’s start with a disclaimer—at the helm, you are the captain. No book, guide, app, or article can replace good seamanship and sound judgment. Whether you bring a family cruiser, a daysailer, a kayak, or even a bicycle, the adventure is yours to shape.
Charts, Plotters & Navigation
Conventional wisdom: Buy the biggest, best, and most expensive chart plotter.
Reality: While a high-end multifunction plotter is nice, it’s far from necessary. At minimum, a first-time visitor should have a NOAA navigation chart #18421, a compass, and a basic GPS—or even just a smartphone. At some point, you’ll find yourself staring across miles of open water at an unfamiliar shoreline, only to realize you’ve drifted off course. A simple compass and chart will keep you pointed in the right direction, saving time and frustration.
Extra tip: A colorful road map is handy for identifying landmarks—something navigation charts won’t show.
Currents & Tides
Newcomer’s fear: Treacherous 15-knot currents, whirlpools, and impassable passages.
Reality: While strong currents do exist, they’re entirely manageable with a little planning—just like avoiding rush hour traffic. Most horror stories come from winter storms, poor seamanship, or bad decision-making.
During the summer cruising season, inner-island currents rarely exceed 1.5 knots, and in the straits, 2.5 knots. Understanding the tides makes all the difference.
Here’s what you need to know:
- Currents are always moving. There’s rarely a moment of slack water, except for brief pauses at tide changes every six hours.
- Fast boats can ignore currents, but slower boats must work with them. A sailboat doing 4.5 knots against a 2.5-knot current is effectively crawling along at 2 knots. But ride with the same current, and you’re cruising at 7 knots. Plan wisely, and a 10-mile passage could take 90 minutes instead of five hours.
- Narrow Passes funnel water, increasing flow speed only within the pass. Smart sailors time their arrival at passes so the water pushes them in the right direction, rather than fighting the tide.
Current forecasting books and programs are available, but a simple tide forecast and a chart will do the trick.
As a rule of thumb:
- A flood tide (incoming) generally flows north.
- An ebb tide (outgoing) generally flows south.
With just a tide table, a clock, and a chart, you can plan your day—maybe delaying departure until 11 a.m. for a favorable current or setting out early at 7 a.m. to get ahead of the tide, is all you need to do.
Tip: You don't need an annual book. Simply go online and print a page or two of the tides forecast during your voyage.
