The Puma Advantage
Nortek has provided a four-beam DVL to Puma Ocean Racing. The sensor head is mounted in the bottom side of the lead bulb of the keel. The beams are oriented forward, aft, and abeam. Along each beam there is a single measurement “cell” where the along beam velocity is measured. The position of the measurement cell is well below the boat and therefore in water undisturbed by the hull and appendages. The DVL has a special firmware which outputs a data stream at a 4 Hz rate. The DVL data at this point is incomplete and requires further processing.
Two views illustrating the acoustic sensor head, that is composed of four transducers.
The next step is to stream the data to the onboard computer which also receives data from the inertial motion sensor, and the keel cant angle sensor. The velocity and orientation measurements are then processed to output forward boat speed and leeway.
Currents can be directly estimated in real time by differencing the GPS boat speed and the true through-the-water boat speed. Nortek believes this is the highest quality current estimate in yacht racing history.
A view from the top down on the boat illustrating the beam orientation: fore, aft and abeam.
It is perhaps a little fanciful to present this as a simple recipe for estimating leeway and currents. The reality is that the success of this collaboration is a result of persistence and understanding that the many challenges discovered underway could only be solved with a strong engineering and technology team. Behind this somewhat simplified overview were countless hours of data gathering, methodical testing, electronics development, data interpretation, and patience from a team focused on one thing: winning the Volvo Ocean Race.
The DVL
developed for Puma Ocean Racing is a custom solution. Nortek does not offer such a sensor for the
yacht racing community at this time. If
you have a special project that could use a DVL we encourage you to contact Nortek
in your region
Nortek looks forward to providing greater details of how this new system is helping the Puma Ocean Race team optimize their boat speed. Stay tuned for future news installments here and for announcements about this being the topic of one of Nortek’s future symposia.
