We had to return to Anacortes from Friday Harbor because we were still concerned that the GPS/Autopilot might still give us trouble up stream. There we had Brian, the owner of Anacortes Marine Electronics, aboard (on a Sunday and the Fourth of July too!!!) to assess things but he could find nothing amiss so we took off for parts north the morning of the 5th.
We cleared customs by phone for Montegue Harbor where we snagged a mooring buoy and spent a quiet night in beautiful weather. The next morning we made a five hour run for Dodd Narrows, south of Nanaimo. The tidal currents run through Dodd at up to 8 knots and we are a 7 knot boat. You see the problem. So, we have to time our arrival at places like Dodd to coincide with the change in tides which is called slack water. Part of the fun of boating is making these calculations.
The hour run between Dodd and Nanaimo is open to the Straits of Georgia where the wind often blows so this stretch can sometimes be a little rough and we did take a spray of water on the windows once in a awhile. Nonetheless, we found good anchorage behind crowded Newcastle Island where we watched the seaplanes come and go and, later, the city lights of Nanaimo. There was some wind but the weather was expected to improve the following day. Usually, one crosses the Straits early in the morning before the afternoon winds typically pick up. The wind was still blowing in the morning but the wind dropped about noon, as predicted, so we made an unusual afternoon run to Pender Harbor in flat water.
Prideaux Haven Vista
Desolation Sound: After a night and a disappointing diner at the Garden Bay Marina in Pender Harbor we made the seven hour run in fine weather to Prideaux Haven in Desolation Sound. The cove itself was a little crowed, as usual, so we anchored for two nights behind little Rophy Island http://www.yknot.ca/images/desolation-sound.gif. to enjoy the views. By 7:00 pm he thermometer had climbed to 93.
Each day there are two high tides and two low tides. Each are about 6 hours apart and the times of the highs/lows advances about an hour each day. During each lunar cycle there are two periods of small "Neap" tides and two large "Spring" tides. Each lasts about a week. We are at Spring tides now. The water "floods" in from the ocean following low tides and "ebbs" out following the high tides. Ebb currents are almost always stronger than flood currents. Today's tidal difference is 16 feet. Image billions of gallons of water behind a narrow opening. Now image that water is 16 feet higher than the water outside the opening. All that water comes out like a fire hose creating tidal rapids. These currents can reach up to 20 knots in some places on the coast. Sometimes the water in the channel will look like a 4 or 5 foot waterfall moving through. Around points of land big whirlpools can open up out of no where. Because "white" water is full of air it is less buoyant. Boats ride lower and the propeller and rudder loose their "bite" in the water. Smaller boats can and do sink. Slow boats like "Intrepid" can not run against even relatively small tidal currents. Between Desolation Sound and Johnstone Straits await five tidal rapids that must be "climbed". From south to north they are Yaculta, Gilliard, Dent, Green Point and Whirlpool Rapids. We must time our arrival at these rapids with the turn of the tide - slack water. Sometimes the period of safe transit is only 15 minutes either side of slack water. The distances are such that we can not time all the rapids in one day. In most years we can make Forward Harbor, just North of Whirlpool in two days. This is not one of those years. We timed Yaculta and nearby Gilliard for 10:45 am slack with no problems. However, the skipper underestimated effect of the opposing current on the time required to get from Gilliard to Dent Rapids. We were trying to make for the far shore where the current is least when we were cut off by a southbound sailboat that was being flushed through. We found ourselves in the "Devils Hole" against at least a 4 knot current just as the whirlpool was beginning to form. You get the picture. We couldn't make much headway and we didn't have a lot of steerage. We got tossed around pretty good but made it through OK. It was only about 5 minutes but it got our attention. Here's a video of Aaron Rapids running full tilt. Aaron is a few hundred yards from Dent Rapids. http://www.youtube.com/watch?v=pCDB9CZ41Kc What we experienced was nothing like this, though.
A couple of hours later we pulled up behind some islands to wait for the next slack so that we could get into Blind Channel Resort for the night. http://www.blindchannel.com/ We celebrated Rolynn's birthday a few days early with an outstanding dinner. Blind Channel is one of three area resorts begun by immigrant German families in the early 60s. Originally focused on salmon fishing they have become more resort like as the fishing has diminished. Blind Channel is now operated by the third generation and the fourth is crawling around on the floor.
Getting back to currents. When the wind direction is against the direction of the tidal currents the water gets pushed up into close steep waves. This is the classic "wind against tide" scenario. Since ebb currents are stronger than floods one is especially careful about wind against ebb tides. Johnstone Straits http://en.wikipedia.org/wiki/Johnstone_Strait is 68 miles long, a maximum of 3 miles wide and several hundred feet deep. It runs mostly East to West and is bounded on both sides by steep mountains which funnel the wind. It is the only path for thousands of square miles of water to enter and exit this area. When high pressure sets up off the west coast of Vancouver Island, as it has, "westerlies" (winds from the West) blow into the straits against the tide ebbing out. The result is REALLY nasty seas. (Note: The huge Frazier River empties trillions of gallons of water into the Straits of Georgia near Vancouver, BC. This fresh water floats on top of the denser salt water. Global hydraulic effects force this water NW through Johnstone Straits. So, there is always a surface ebb current flowing westward in the Straits. When this surface ebb coincides with the west bound tidal ebb it really snorts.) Oh, in order to get farther north boats must go into the straits for at least 14 miles. (Note: All distances are nautical miles - 1.14 statute miles.) To further complicate matters, the summer pattern is for winds to be lightest in the morning, then rise to their max by late afternoon, then diminish over night. The question is how light is "light" how max is "max" and how diminished is "diminish". On top of that, currently the winds are lightest when the ebb tide is strongest. What to do - go in lighter winds and strong current or strong winds and light currents? We will opt for the former.
So here is the current scenario. We are at Blind Channel - two hours and two rapids away from Forward Harbor where we will wait for good conditions in the straits. We had planned to go through Green Point Rapids this morning, wait in Longburough Sound for the afternoon slack, then go through Whirlpool Rapids to Forward Harbor for the night. There is a 45 knot westerly blowing in the straits now (51 mph) against a big ebb and conditions tomorrow (Tuesday) are uncertain. The winds are supposed to be NW 5-15 kn Wednesday morning rising to 20-30 in the afternoon. But, the strong ebb current will persist two hours later in the morning (when the wind begins to rise) than today. (Remember, the tide cycle advances an hour per day.) So, we will stay here tonight, go to Forward Harbor tomorrow then wait and see.