Two routes lead north along the Inside Passage in lower British Columbia, from urbanity, highways, and talk shows on the radio to the welcome wilderness of central and northern British Columbia. Both offer challenges and the opportunity to take a beating from the sea. One is a long haul through often stormy waters, but with hardly a need to change course for a couple of days, while the other curls among islands and waterways, turns from narrow channels to major inlets and vessels glide past snow-topped peaks along the shore.

Those routes have one extraordinary thing in common–courses that lead through rapids with currents to 10 knots or more, with whirlpools, overfalls, and a reputation for overwhelming the unwary boater.

One course, along the east shore of Vancouver Island, has one whopper of a rapids–Seymour Narrows, which runs at a maximum of 16 knots. The other, a route among the islands and waterways along the west shore of mainland British Columbia, has five similarly vigorous rapids. That’s my choice nearly every season.

The Vancouver Island route, favored by commercial vessels, cruise ships, and many boaters, offers, in my opinion, either boredom or some degree of terror as the wind and sea mix it up. There are a couple of days running straight up Georgia Strait–then a shot at Seymour Narrows–and finally another long day up Johnstone Strait. Both waterways can be violently rough, particularly in spring and summer when northwest winds blow in the afternoon.

Choosing the mainland route requires a two- or three-hour crossing of Georgia Strait, but then it follows Malaspina Strait and better-behaved Lewis, Calm, and Cordero Channels to the choke point between Stuart and Sonora Islands where three of the five rapids are spread over a little more than 4 miles of waterway. During large tides, currents rip through the first three (Yuculta, Gillard, and Dent) at 10 to 12 knots. These are not laminar flows: strong tidal streams with overfalls, violent eddies, and whirlpools are common at maximum flows.

My goal is to motor through the rapids at slack water–the fleeting moment when the current halts its flow in one direction and readies to storm the other. Tide and current tables make it work. But it’s not always easy.

Government tables use flows in Gillard rapids–the one in the middle–as the base for its calculations. The day we took Quadra through, slack water at Gillard was at 1314 hours. The problem: slack at Yuculta rapids, the first in the chain, was 25 minutes after Gillard that day and, to confuse things more, slack at Dent rapids–the final rapids and the worst of the bunch–was about 14 minutes earlier than Gillard. There’s no way to pass through each at its moment of slack. I’ve taken boats through those rapids perhaps dozens of times over my years of cruising in British Columbia. I fussed a lot with current tables and continue to fuss over times, speed over the ground, and miles to travel. The calculations can make your head spin. And minutes do count. Arrive too early or late and you may be in for a bruising.

If there were a tight little harbor at the foot of the rapids, where one could anchor to await calm water in the rapids, life would be easier. There is no such place. Most of the boats heading through come from Desolation Sound, which is two to three hours away, depending on boat speed. So one must calculate slack in the rapids and figure how long it will take to get there through channels with light but variable currents.

Finally, one year I decided the only rapids to worry about was the one off Little Dent Island. The channel is narrow and its bottom is irregular and the sea, flowing through at speed, is wild and dangerous.

So now, I determine slack at Dent–1300 hours on this run–and then figure how long it will take to cruise there from Yuculta rapids if I am northbound. Usually, it’s about 30 minutes. But wait, there’s another complication. The Canadian Cruising Directions, a publication similar to the U.S. Coast Pilot, recommends that slow, low-powered northbound traffic enter Yuculta during the dying flood. Most of the popular cruising guides copy this information and it’s widely regarded as the way to go. We were northbound, but going in at slack ebb. The wrong time of day. Slack flood times that day were at 0700 hours and at 2024. Neither worked for us. So I defied common wisdom and cast off in time to hit the rapids at slack ebb.

My calculations worked. Other boaters made the calculations and came to the same answers, which boosted my ego a bit. We motored into Yuculta rapids at 1230 and turned uphill, gaining speed as we were swept along by the fading ebb. There were no whirlpools, nor did we get jerked off course by swirling currents. Making the left turn into Gillard rapids, we watched dozens of seals hunt for a late lunch, probably hake. Eagles watched from trees on Jimmy Judd Island, waiting for their chance at the fish market.

Quadra slowed as we motored through Gillard and then accelerated beyond her normal 7 knots as we neared the worst rapids of them all–at Little Dent. My favorite description of turmoil at Little Dent was written by Katherine Pinkerton, who cruised in that area in the mid- and late 1920s with her husband and their daughter. Her book, Three’s A Crew, first was published by Carrick and Evans in 1940 and it’s in my floating library. There were a fair number of people living near the Yucultas in those days (logging, mining, fishing brought them) and they observed the maximum flood through the rapids as sort of a holiday.

“Henry Maurin was king of the Yucluetaws,” she wrote, using spelling common to those days. “He was the only man who ran them in a gas boat at any stage of tide, day or night.

“Henry celebrated his kingship each year with a picnic on Little Dent Island at the north end of the rapids. The date was selected by the full moon of June, when the biggest flood of the summer poured through the narrows.

“Everyone went in Henry’s boat leaving on the last of the ebb. After we’d carried the baskets across and built a fire and boiled tea we ate lunch on a high rock and watched the Yucluetaws put on their show.

“Little Dent Island lies in mid-channel and forces the tide into its narrowest and swiftest place. The flood began with a low mutter and the current swept along, fast and smooth and straight. As the tide massed its forces and the great push began the mutter grew to a dull roar. Current snarled along the shore and there was no longer a smooth straight sweep. The resistless power of that steady rush of tide threw the whole rapids into mad confusion.

“A great tree trunk came lunging down and a whirlpool seized it, stood it on end, waltzed it around and sucked it from sight. A quarter of a mile beyond, the tree was spewed out and tossed into a fresh welter of turbulence and confusion.

“And when the great tidal push increased in power, the roar intensified. The whole surface of the channel would lift suddenly. Then I understood why the Yucluetaws had been known to put a large steamship on its beam ends.”

I was thinking about Katherine’s story as Ellen steered Quadra into the heart of the Little Dent rapids. We may have been a few minutes ahead of slack, but the sea swept us along swiftly and easily. Despite my fussing over numbers the night before and my worries early that morning, it was an easy trip–as smooth as satin. I’ve never observed the turmoil Katherine described, and I never will.

What about rapids four and five? We rolled out early the next morning and hit Greene Point rapids at 0700, slack flood. We then picked up an ebb that gave us 2 to 3 extra knots of speed and scooted through Whirlpool rapids as if they weren’t there.

The rapids: one reason I love the Inside Passage.