Max Ebb — Drag for Poor People

In December’s Latitude 38, Max Ebb draws on Lee Helm’s expertise to find a solution for a technical question regarding a long-distance race boat.

I had calculated correctly that Lee Helm, grad student in naval architecture, would still be awake this late at night. And I needed to solve a technical problem: A friend at the yacht club was gearing up for some long ocean races in the spring and summer, and wanted me to help calculate what kind of battery charging system would slow the boat down the least.

I typed:

“Lee, this guy is a fanatic about extra drag. He wouldn’t even let us put a fishing line overboard on a race to Mexico a couple of years ago. At least, not till the standings had us in the bottom half on corrected time. Then we went into cruise mode, and caught a very nice yellowfin.”

Lee responded:

“For sure. Nothing takes the drive out of a crew like knowing that they’re at the tail end of the fleet in a long ocean race. My grandfather said that in his day, there were no trackers and no check-ins; and no GPS, so even when there was a roll call, the positions could be way off. The good part was that the crew raced hard, all the way to a last-place finish.”

Which prompted from me:

“Watch this ‘grandfather’ stuff. I remember those days too. We could imagine we were winning, right up until we came around the last breakwater after finishing and saw how many of our competitors were already tied up at the guest dock.”

Lee came back with:

“I can see how it must have been better for crew morale, to keep the pedal down when there’s always even a thin chance you’re awesome.”

Finally I got around to asking my question:

“My friend needs to know how much drag his boat is producing at various speeds, so he can figure out how much time is lost when he uses a water turbine for battery charging. He sent me his ORR certificate, which is full of all kinds of good performance info, but it never actually publishes the resistance curve. That must be in there somewhere under the hood.”

Lee answered:

“For sure, but there are ways of backing it out.”

Find out what those ways are by reading the full story at Latitude38.com.