Nortek Doppler Velocity Log, measuring Puma’s leeway across the pond
I learned that the Volvo Ocean Racer Puma had a very special speedo when the race started off around the planet last Fall, but was hoping that I or a Panbo guest blogger would get to see the other end of the system when the fleet visited Miami. Well, right now Puma is leaving Bermuda to starboard as it zips across the Atlantic toward Lisbon, and while Panbot Jeffrey Schwartz witnessed her Florida first place and did get some time with major VOR supporter Inmarsat, he was not able to wrangle his way into any racer’s nav station. But let me tell you what I do know about the Nortek Doppler Velocity Log…
The main thing to know is that the DVL measures a boat’s speed through the water both forward and sideways, using four ultrasonic sensors so sensitive they can track plankton. With those values plus SOG, COG, and Heading the mysteries of boat motion, and sail performance, are theoretically solved. Now this sort of thing has been around for a while — as in the JRC Doppler Sonar and some gear I once saw at Airmar HQ. But that gear is BIG while the Nortek DVL is quite small and was apparently faired into Puma’s keel so well that it has less drag than a paddle wheel sensor.
I learned that last bit from an excellent Sailing Anarchy video interview with Puma tech Rob Hopkins. He explains how valuable it is to measure leeway accurately, especially on a boat with both adjustable swing keel and dagger boards that can influence it…
But it’s a Wired Sports article that reveals: “Skipper Read is quick to point out that the DVL was just ‘one of a thousand factors’ that contributed to the crew’s victory, but nevertheless acknowledges the advantage granted by the previously top-secret device. With an exclusivity deal that prohibits Nortek from selling the technology to another Volvo team for the duration of this Ocean Race, the crew can sail assured that their edge will be preserved throughout.”
The question I’m sure some racers and other sensor geeks may have is if they can get a DVL for their boat and, if so, at what cost? But I don’t see any information about that at Nortek AS, which primarily specializes in fixed current meters. Anyone know more?
I’ll add that while I haven’t followed this Volvo Race as closely as some others, the online tracking is pretty sensational. And I did really enjoy some near-live video of the boats working their way through the Bahamas in flat seas and light airs (and still going fast). I can’t find those particular videos but this compilation of leg six is good, and even includes Puma skipper and rare VOR yank Kenny Read quoting Hunter Thompson: “When the going gets weird, the weird go pro!” Go Puma!