Obstruction Pass 2
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Obstruction Pass separates Obstruction Island from the south end of Orcas Island. It's the main gateway between Rosario Strait and the inner San Juan Islands, and it's only about 350 yards wide at its narrowest.

Timing

Currents through this stretch of Rosario Strait — Obstruction, Peavine, and Thatcher Passes together — can run 3 to 7 knots. Plan around slack or a favorable current, especially at night or in reduced visibility.

Coast Pilot, In Plain Words

Here is what the U.S. Coast Pilot says about Obstruction Pass and the water around it. The official text is below.

Read the official text

Local magnetic disturbance

Obstruction Pass, with a least width of 350 yards, separates Obstruction Island from Orcas Island and leads west from Rosario Strait to the inner passages and sounds of the San Juan Islands. A launching ramp and float are on the north side of the pass about 0.6 mile northwest of Deer Point; depths alongside the float are about 4 feet. Caution is advised because of the numerous private pilings and moorings in the area. Obstruction Pass is marked by a light on the northeast side of Obstruction Island.

Currents

The currents through Obstruction and Peavine Passes have estimated velocities of 5.5 to 6.5 knots at times. Heavy tide rips occur east of Obstruction Island.

Tides and currents

See the Tidal Current prediction service at tidesandcurrents.noaa.gov for specific information about the times, directions, and velocities of the current at numerous locations throughout the area, including Rosario Strait and vicinity. Links to a user guide for this service can be found in chapter 1 of this book. The currents in Lopez, Thatcher and Obstruction Passes are reported to attain velocities of 3 to 7 knots. This should be kept in mind when proceeding through Rosario Strait, particularly at night or in thick weather. On the ebb of a large tide off the entrance to the passes, a south wind causes tide rips that are dangerous to small craft. In the area northwest of Belle Rock (48°29'35".N, 122°45'10"W.), mariners may experience a strong set to the west during ebb currents flowing out of Guemes Channel.

Source: U.S. Coast Pilot 10, Chapter 7, 7 ed. (NOAA, Office of Coast Survey). Updated weekly. Official Coast Pilot ↗

Local Knowledge

  • Watch out

    The current can run 5.5 to 6.5 knots here at times, with heavy rips building up on the east side of Obstruction Island. A south wind against a strong ebb makes the rips worse right at the pass entrance.

  • Tip

    There's a launching ramp on the north side of the pass, but the water alongside is only about 4 feet deep, and private pilings and moorings crowd the area. Stay in the main channel.

  • Timing

    Currents through this stretch of Rosario Strait — Obstruction, Peavine, and Thatcher Passes together — can run 3 to 7 knots. Plan around slack or a favorable current, especially at night or in reduced visibility.

Plan a Trip Through Obstruction Pass

1. Start from

Nearest harbor on each side of the narrows. Pick a side to start there.

2. Cross to the other side of Obstruction Pass

Rosario Resort Marina → Obstruction Pass · 3.7 nm · ~0h 28m at · from the northwest

Stations & Data

Times are NOAA predictions, not live readings. Open a station for its full tide and current charts.

Questions

What is Obstruction Pass?
Obstruction Pass separates Obstruction Island from the south end of Orcas Island. It's the main gateway between Rosario Strait and the inner San Juan Islands, and it's only about 350 yards wide at its narrowest.
When is the best time to go through Obstruction Pass?
Currents through this stretch of Rosario Strait — Obstruction, Peavine, and Thatcher Passes together — can run 3 to 7 knots. Plan around slack or a favorable current, especially at night or in reduced visibility.
What should I watch out for at Obstruction Pass?
The current can run 5.5 to 6.5 knots here at times, with heavy rips building up on the east side of Obstruction Island. A south wind against a strong ebb makes the rips worse right at the pass entrance.
What does Class 2 mean?
Class 2 is BoatRoutes' own 1-to-5 rating of how costly a timing or judgment mistake is here — it is not a NOAA scale. Class 2 means one thing to plan around (depth, a schedule, or mild current); getting it wrong costs time, not safety.

Predictions, not observations · U.S. Coast Pilot 10 (7 ed.)

U.S. Coast Pilot text is a work of the U.S. Government and is in the public domain. Per 17 U.S.C. §403, no copyright is claimed in that text. BoatRoutes is not endorsed by NOAA.