The message below is the full press release from Nortek and the PUMA
Ocean Racing Team -- for questions or comments, please chime in on the Nortek Facebook page.
“The collaboration between Nortek and the
entire PUMA team has resulted in an tool that provides unique information to the
sailing crew. They can now measure
leeway, a first in sailing, and use it to measure ocean currents much more
precisely than ever before,” said Atle Lohrmann, CTO of Nortek.
Nortek started
developing this capability during the 2008 Star class Olympic trials with the
Norwegian team skippered by Eivind Melleby, also a veteran of the Volvo Ocean
Race. Nortek went on to work with the TP52 ocean racing team Caixa Galicia with a predecessor to the
existing sensor with Caixa navigator
Robert Hopkins.
“This is the
biggest advancement in sailing instrumentation since the invention of the GPS,”
said Hopkins, who runs performance testing for PUMA and worked with Nortek on
the project. “Nortek adapted their new DVL technology to our sailing
performance needs, to measure very high speeds along the boat's track and very
low speeds across it. With Nortek's history of deploying instruments on buoys
in hostile Arctic conditions, we knew that we could trust the Nortek DVL in a
race around the world.”
Leeway is the sideways skidding angle a boat makes as it
sails forward. Leeway can be changed on a Volvo Open 70 yacht by adjusting the
daggerboard immersion and canting the keel. The adjustable daggeboards and keel
act like wings underwater to counteract the force of the sails. The crew relies
on Nortek DVL leeway measurements to optimize PUMA's Mar Mostro performance
at all times, providing the core data upon which every other performance
measurement is based.
“I can't tell you how important it is to finally
know how fast the boat is going in all conditions. We really feel this is the
first time boat speed has been accurately measured without using various types
of cumbersome and complex tables within the boat’s instrumentation. It’s a huge
factor for something as simple as a sail change or as complex as routing,” said
Ken Read, skipper of the PUMA Ocean Racing team. “Nortek and our entire team,
especially the shore crew, worked diligently to make this project a reality.
The technology already helped us to win the Transatlantic Race in July, and it
will be a key component as we race around the world.”
The Nortek
DVL uses acoustic techniques to measure water velocity along each of the four
beams. The sensor is mounted in the
bottom of the lead bulb of the keel. The acoustic beams are oriented forward,
aft and abeam. Data from each beam is
streamed to the on board computer which also receives data from the inertial
motion sensor and the keel cant angle sensor. Velocity and orientation
measurements are then used to output true forward boat speed and leeway. Real
time currents can be directly estimated by differencing the GPS boat speed over
ground and the boat speed through the water.
Similar
systems were developed for the seismic survey fleet and Nortek recently
delivered the first operational navigation system to Fugro-Geoteam in Oslo to be mounted on two
Barovane seismic diverters. The
diverters keep the towed acoustic streamers separated and like the Puma-DVL,
the system measures the angle of attack, the through water speed and ocean
currents near the surface. The
difference was the space available for the acoustic transponder. “We worked very hard to miniaturize the DVL
unit that was installed aboard PUMA’s Mar
Mostro,” stated Lohrmann.
The project
is an important milestone for Nortek because it demonstrates how well the
acoustic Doppler technology performs in very challenging conditions and that
the system can be fully integrated into modern navigation systems. The fact
that the PUMA Ocean Racing technology
team was able to integrate the DVL with other sensors on the boat is a
testament to the quality and sophistication of modern yacht racing.
The PUMA Ocean
Racing team sets out on the first leg of the Volvo Ocean Race 2011-2012 on
Saturday, November 5, departing Alicante, Spain, for Cape
Town, South Africa.
The 11-member crew will travel 39,000 nautical miles over nine months, sailing
from Alicante to Cape Town, and on to Abu Dhabi, UAE; Sanya, China; Auckland,
New Zealand; around Cape Horn to Itajaí, Brazil; to Miami, Florida, USA;
Lisbon, Portugal; Lorient, France, finishing in Galway, Ireland in July 2012.
For details about the PUMA-DVL,
including images and example data, please visit our website http://www.nortek-as.com/puma-ocean-racing
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