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WE'RE GOING SLOW, & WE LIKE IT (MOST OF THE TIME)
By Robert Hale.
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January 15, 2003. For the first few years, we motored the boat slowly until the engines were thoroughly warmed up, then moved the throttles forward to 2400 rpm, which gave us about 16.5 knots through the water. The boat was planing cleanly, the wake flattened out, and we thought we were happy.
Then, a couple years ago, we decided not to wait in line for fuel at Klemtu, far north on the central B.C. coast, and turned the bow toward Shearwater, some 40 miles away. Our tanks were getting low, however, and we throttled back to 1500 rpm (8.5 knots) to conserve what fuel we did have left.
Several things happened. To our surprise, it didn't take that much longer to get to Shearwater than earlier trips. We enjoyed the scenery more and we arrived rested instead of tired. Last, it seemed as if the fuel gauges hardly moved. Intrigued, we ran at 8.5 knots as we worked our way south. Same results: Passages didn't take that much longer, we saw more, felt less strain, and boy, was it easier on the fuel!.
Since then, most of our running has been at 8.5 knots, which is very close to hull speed for our Tolly 37. We do feel as if we're wasting the potential of the pair of 270-horsepower diesels down in the engine room, but the mechanics say we're not hurting the turbochargers, and the slower speed just has to be easier on all the mechanical parts.
And there are times when it's nice to have those big engines. Twice, now, we've been able to run from Sunderland Channel (north of Desolation Sound) to Campbell River in one passage. We powered uphill--literally--through a smooth-flowing 4-knot ebb at Whirlpool Rapids, ran at 16.5 knots down Chancellor Channel and through a dying but still noticable ebb current at Greene Point Rapids, and arrived at Seymour Narrows exactly at low water slack. Once through Seymour Narrows the building flood current pushed us south to Campbell River. In each case our day began well north of Sunderland Channel--the first time at Port Harvey, near the north end of Johnstone Strait; the second time at Cutter Cove, near Knight Inlet. We ran at 8.5 knots until we reached Whirlpool Rapids because there was no point running faster, only to wait for the rapids to quiet down. We saved the speed until we needed it, and when we needed the speed we had it.
We like to say we have a two-speed boat: 8.5 knots and 16.5 knots.
There's a further benefit to slower speed running, engine life. Engine longevity can be measured in engine hours or in the gallons of fuel burned. From what I've read, my higher-speed diesels should be good for 25,000-30,000 gallons of fuel. Running at 8.5 knots most of the time, our typical fuel usage is in the neighborhood of five gallons per engine hour, including whatever the generator and the diesel furnace burn. Each engine, therefore, burns about 2.5 gallons per hour. Assuming a 25,000 gallon engine life and 300 engine hours per year, that's 33 years. I'm 62. Take 62 plus 33 . . . hmmm, I don't think I'll wear these engines out.
Not every hull or engine is happy at slower speeds, and certainly not every skipper would be happy just poking along. In our case, though, the question, "How fast does it go?" is beginning to fall into the same category as "How many does your boat sleep?" I can provide an answer, but I'm not sure it means very much.v
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