Max Ebb: Scallops on the Bay
“The only good knotmeter is another boat alongside that’s trying to beat you.” That’s according to Lee Helm, who likes to scold me with that reminder every time I call out a speed number from the instrument panel.
Lee usually finds newer and faster boats than mine to race on, but since most of my regulars were not available that day, I put Lee in charge of recruiting. She brought a handful of students from various graduate programs at the university: We had a history major and former intercollegiate racer assisting in the cockpit, a chemical engineer new to sailing at the mast, and a genuine merchant mariner — second engineer on a tugboat — running the foredeck. They seemed trainable, but it would take more than one race.
Sailing out to the starting line, beating to weather in a medium breeze under main and number one, it seemed like a perfect time to give my new cockpit crew a turn at the helm. Lee, having put some planning effort behind her frequent advice about the limitations of knotmeters, had arranged for a slightly larger and slightly faster boat in our division to rendezvous with us before the start, for some speed testing. They hove into view well to windward, sailing a deep reach to intercept, and brought up into the wind in a position to windward and a little ahead. The maneuver put both boats in clear air with neither boat affected by the other’s wind.
“Good work, making trees,” I complimented the history student after our relative speed and angles had stabilized. I could see the bow of our trial horse to windward dropping back ever so slowly against the background shoreline. “Higher and faster!” I said, thinking that I might have stumbled into a natural upwind driver.
“And that boat, like, owes us time,” Lee added.
But it didn’t last. The other boat found their groove, and we started to drop back very slowly. We were still tracking a little high, but the other boat’s bow was starting to cover up shoreline.
“Bring it down a little,” I advised. “Let’s get our speed back, then we can poke it up again.”
My crew did exactly that, and the knotmeter needle edged up a little. Lee eased the jib barber hauler ever so slightly, to widen the sheeting angle without introducing too much twist. Then we came up to the previous wind angle with enough speed to recover our loss as the jib was trimmed in again.
Lee couldn’t see the knotmeter from where she was positioned, but somehow she seemed to know when we had our speed back and it was time to trim for high pointing.
“It’s the sound of the bubbles,” she said when I asked her how she did it. “Like, power is proportional to speed cubed. If we accelerate from, let’s say, 6 knots to 6.3, that’s a 5 percent speed gain. But the power increase is an extra 5 percent cubed, which is more like a 16 percent increase in power and a 16 percent increase in energy left in the water in the form of waves, bubbles and foam. That’s a big change; even a human can detect it. And that’s why an experienced skipper who knows their boat can usually estimate speed with, like, awesome precision. The fun gauge is just a crutch.”
“I always wondered how old-time navigators kept an accurate dead reckoning without a knotmeter and with only very occasional use of their chip log,” I replied.
