nke Depth and Speed sensors explained

We are constantly reporting on the latest innovations in the marine industry which offer weight savings whilst, at the same time, increasing safety factors. The result: lighter, faster, safer and more exciting sailing.


nke sensors-1

Image Credits: nke

The marine industry has been awash with new and exciting technological innovations in recent years and, standing at the forefront are companies like nke marine electronics. nke are the standard for the majority of mini-transat and IMOCA 60 classes. They provide electronics for many different functions and for many different types of sailor. You can find out more about the full range of nke products available on our website here.

This blog will focus on the nke speed and depth sensors. Good quality sensors are key to good autopilot performance, but location and water conditions are also factors in choosing the right sensors for your boat.


Depth Sensors


The nke Depth Sounder

Depth sounderThe nke depth sounder can provide depth values in metres or feet depending on your preference. With a range of up to 50 metres, the nke depth sounder is able to give depth either from below waterline or below the keel depending on your preference.


Speed Sensors

All nke speed sensors can measure boat speed and the temperature of the water, to varying degrees.


Paddle wheel speed sensor

Paddle Wheel speed sensor

The classic speed sensor, the paddle wheel, is a great choice for many types of sailors, for racing, cruising or offshore sailing. Reliable, cost effective and compact, this sensor will certainly prove more than adequate for the needs of most sailors. The biggest downside of the paddle wheel sensor is that weeds and other sea debris can occasionally get caught in the sensor's moving parts.


Ultrasonic Speed sensor

ultrasonic speed sensor

The Ultrasonic sensor ends the problem of wheel blockage because it has no moving parts. It is a great choice for racers as the sensor is installed flush, meaning no drag. The ultrasonic technology allows anti-foul paint to be applied to the sensor, leaving it clean all season and cutting down maintenance. The Ultrasonic sensor will also not need calibration as frequently as the other sensors. However, it should be noted that in murky or dirty water, the ultrasonic sensor can lose a degree of accuracy.


Electromagnetic speed sensor

Electromagnetic speed sensor

The electromagnetic speed sensor is the top of the nke range and gives highly accurate data in all waters, including low visibility. It also has no moving parts and is a robust and compact device which will not create drag in the water and is unlikely to get caught on any weeds or other debris. 


Which sensor should I choose?


There is not a great variation in performance from the three speed sensors listed above. The electromagnetic sensor and Ultrasonic sensor can measure temperatures of -10 to +50°C, whilst the paddle wheel can measure 0°C to +50°C. All three sensors can measure speeds up to 35 knots.  


For cruising and casual racing, the paddle wheel speed sensor will prove to be more than sufficient for the vast majority of sailors. It’s cost effective and a great all-round speed sensor.


For professional sailors, it all depends on where you will be sailing. In waters with low visibility or high levels of sand, mud and other sediments, the electromagnetic sensor will be best suited to maintaining accurate results.


But, for the majority of competitive sailors sailing in clearer water, the ultrasonic speed sensor is accurate and reliable. It is the least vulnerable to fouling and is also generally very low maintenance and a great choice!


Log / Sounder Interface

Regardless of which speed sensors you choose, you will need this interface to connect the depth and speed sensors to the topline bus. nke offers both single and dual log / sounder interface options, with the dual interface offering an additional slot for a second speed sensor. This is designed for boats such as multi-hulls or wide mono-hulls where one speed sensor would spend significant periods out of the water


Where should I position the sensors?


The placement of the depth and speed sensors are depend on the type of boat you have.

On a sailboat, the ideal position for the sensors is in front of the keel, along the axis of the boat. The diagram below shows the proper positioning.

Depth sensor reccomended location


For motor boats:

reccomended location for the speedometer sensor


It’s important to line the sensor axis parallel to the centre (Lubber) line of the boat to ensure accurate calculations.


The sensors are fitted through the hull with a through hull fitting. These usually come with the sensor, but a replacement fitting can be purchased here.


For more information on nke and our range of electronics, click here or if you are interested in looking at upgrading your boat navigation electronics please get in touch using the link below...


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