What is a WRB

Wave Rider Buoy (WRB)

The WRB plays a critical role in our Dynamic Under Keel Clearance system, this system allows the safe transit of deep draft ships or ships in heavy weather when navigating the harbour entrance. To find out more about DUKC please see.

The Wave Rider Buoy is designed and manufactured in Canada by Axys International Inc and the buoy is called TRIAXYS™ Directional Wave Buoy.

The buoy precisely measures directional waves, capable of producing direction, heights, periods and energy data.  The data transmitted from the buoy can include wave statistics, HNE (Heave, North and East Displacements), Mean Dir (Wave Direction and energy as a function of frequency), directional and non-directional wave spectra, sea temperature, buoy power status, position and alarm messages.

The buoy transmits the data back to Northport every 30 minutes by GPRS (cellphone network) or if this fails via VHF as a backup system.

Compact and rugged, the WRB can withstand the rigors of being deployed in such a wild environment, where it can withstandin excess of 100kn winds and swells of 12m+ and submergence of up to 8m.The buoy’s spun stainless steel hull has a high strength to weight ratio and corrosion resistance, and provides secure mooring and lifting points.

The clear dome allows sunlight to reach the solar panels, while maintaining a low profile and impact resistance. The buoy is solar powered with 4x 104Ahr gel rechargeable batteries to reduce annual operating costs.

The heart of the TRIAXYS™ Directional Wave Buoy is developed from the AXYS WatchMan500™ controller, which integrates sensor systems and provides on-board data processing, data logging, telemetry, and diagnostic/set-up routines. A full directional wave spectrum is computed by the CHC maximum entropy method. Mean wave direction and spreading width are computed as functions of frequency. The software also performs a zero-crossing analysis to compute various time-domain wave parameters. The on-board computer uses an iterative algorithm based on Fast Fourier Transform analysis to solve the full non-linear equations of motion in six degrees of freedom, as measured by accelerometers and angular rate gyros. The buoy is capable of accurate motion data for roll and pitch angles up to 60 degrees. Surge and sway velocities measure wave kinematics that define directional wave properties.

The sensor unit is comprised of three accelerometers, three rate gyros, a Fluxgate compass and the proprietary TRIAXYS™ Processor.

The buoy is moored using a special mooring set-up unlike conventional navigation aid moorings. The key feature required is the need to de-couple the mooring from the buoy to allow unrestricted buoy motions in wave fields. The de-coupling is accomplished by operating the buoy in an untethered free-floating configuration. The mooring is composed of a special extruded 32 mm (1.25”) rubber cord, 15 m in length, terminated with stainless steel compression fittings. The elastic nature of the rubber cord allows the buoy to follow waves in an unrestricted fashion.  The buoy is the tethered to a main mooring line, subsurface floats before attached to its mooring.



Physical Description

Diameter: 1.10m (43.5 inches), outside bumper 0.91m (36 inches)

Weight (including four batteries): 197 kg (435 lb)

Weight (excluding batteries): 90kg (199 lb)

Obstruction Light: Amber LED.  Programmable ODAS flash sequence with three miles visibility.


Hull: Stainless steel

Dome: Impact resistant polycarbonate

Solar Panel Assembly: Fibreglass over foam

Clamping ring: Stainless steel


Processor: WatchMan500TM

Water temperature: Thermilinear composite network

Accelerometers: Flexure suspension servo (Range ±2g)

Rate: Piezoelectric vibrating gyroscope (Maximum angular velocity ±80°/s)

GPS: 12 channel

Power System

Operational system voltage: 11.0to 19.6 VDC

Batteries: 4 @ 12 Volt, 100 Amp hr battery

Solar Panels: 10 @ 6 Watt

Smart Charger: Sunsaver-6

External On/Off Switch: Turns buoy on when Magnetic Key is removed.




- GPRS (cellular)


To see how marine data aquasition works please see Axys International video.

For more information regarding Axys International Inc or TRIAXYS™ Directional Wave Buoy, please see.