JDC's NEW Speedwatch wireless knotmeter is a breakthrough in ease of installation and features. NO wires! NO holes! Mount the impeller under the boat and place the transmitter inside the boat. That's it! Instant speed is transmitted to the display anywhere in the boat, up to 13 feet (4 meters) away.
Unlike GPS, which measures speed over land, the SPEEDWATCH measures your actual speed and distance through the water.

FEATURES:
Easy to install: fix the impeller on the water with 1 of the 3 included fins, place the radio transmitter inside the hull and that's all!
Magnetic transmission through the hull without hole (JDC patent) and radio transmission to the display unit (over four meters)
Current speed
Balanced speed (set by customer)
Average speed of the trip (hundredth of unit)
Maximum speed reached
Display of speed increase or decrease
Distance of the trip
Global distance traveled (over one season)
Units: km/h, m/s, knots and mph
Automatic or manual chronometer
Programmable countdown timer for regatta start
Clock
Waterproof
Possibility to use the existing paddle sensor of your boat
Calibration possible to match any kind of speed sensor
Possibility to fix the display anywhere on the boat and also for each crew member to have his own display unit
Backlight
Low power consumption (around 20'000 km sailed without changing battery)
Velcro strap
Low radio frequency (8,2 kHz)
Min. speed reading: 0,3 knots, 0,5 km/h, 0,1 m/s, 0,3 mph

Advantages over GPS:

While the SPEEDWATCH does not replace a GPS, it does have many advantages when training and monitoring performance:
Instant speed
Actual speed through water
Registers speeds down to 0.3 mph
Tracks acceleration
Countdown timers specific for regattas
Long battery life
Total and trip distances
Using the SPEEDWATCH during training, one can instantly gauge the effect of different paddling strokes, equipment, and sailing techniques, enabling the best performance possible.

The Impeller:
The impeller is mounted under the boat, attached via a fin or clip mount. The small impeller - slightly more than an inch long, spins through the water, in speeds from 0.3 mph (0.3 knots, 0.5 km/h) to over 40 mph (35 knots, 64 km/h). When the impeller spins, a magnetic field is created which is measured by the transmitter - through a hull - up to 12 in (30 cm) away. NO wires connect the impeller to the transmitter! This magnetic transmission is patented technology by JDC Electronic.

The Transmitter:
The transmitter is placed inside the boat, within 12 inches (30 cm) of the impeller. The transmitter picks up the impeller's magnetic field when it is rotating, transmitting the data over 8.2 KHz up to 13 feet (4 meters) away. The transmitter is water-proof, with a replaceable lithium battery. good for 12,500 (20,000 km) of readings. The transmitter can also receive other speed sensors and transmit to the display, which can be calibrated to properly display the speed and distance.

The Display:
The SPEEDWATCH display contains an internal receiver to pickup the information sent by the transmitter, up to 13 feet (four meters) away. The display shows instant and average speeds, distance traveled, trip distance, acceleration, time traveled, and chronometer and countdown timers. The SPEEDWATCH will be an essential tool for training, providing instant feedback on speed and acceleration. Unlike GPS units, the SPEEDWATCH gives true speed through water and distance traveled, versus speed over land. When going against a current, the speed given by a GPS unit will be very inaccurate.
The SPEEDWATCH display can be mounted on a deck or strapped to a wrist or leg. Multiple displays can be used with one sensor . Powered by a lithium battery, the display is water-proof and will register up to 12,500 (20,000 km) on one battery.

Dia: 3.0 in (78 mm) X .70 in (18 mm), Weight: 3.5 oz (100 g)