HOW DOES GPS SEAHORSE STEER SO WELL?

We started with the Standard Seahorse Kontiki, which has an incredible ability to self-steer through varying side currents and waves. This is a unique ability unmatched by others on the market. The long body length of the Seahorse Kontiki allows for unrivalled longitudinal steering stability. The offset tow point and the forward mounted motor, ensures maximum resistance from waves and rough conditions. The long, low body acts like a rudder, removing the need for drag inducing keels or fins. The low buoyancy design also gives the Seahorse the ability to dive under the breaking surf and avoid being washed off course. We have found the line towing behind the Seahorse Kontiki works like the tail of a kite, and this helps to keep the unit straight. The low drag, forward mounted rudder gives the GPS Seahorse the ability to steer and change direction, therefore keeping the kontiki unit heading in the direction you pointed it in.

WHY WE USE THE TECHNOLOGY WE USE.

When Seahorse decided to develop an autopilot kontiki unit we looked at the different means of controlling direction. We first looked at using a compass, as this seemed a easy and simple way of doing it, but the more we looked into it, the more we discovered it wouldn't do the job we wanted done. With a local Tauranga Boys High student, as part of his technology course, we built a prototype to test the concept, and that highlighted many issues.

We found the compass was good at selecting a course, but once motor was started, it was impossible to get the compass further enough away from the motor and wires so it wasn't effected, while keeping the body of the kontiki streamline. We also found if the compass got too close to the black iron-sand, it effected the compass, so you got a different course when you set the course on the beach, compared to what you got once the kontiki was in the water, and the compass was further away from the magnetic ironsand.

We also found the compass would keep the kontiki unit following a compass bearing and side currents would pull it along the beach. This is because a compass knows where it is pointing, but not where it is heading We also found this behavour removed the ability of the kontiki unit to correct itself by tacking into the current, and the compass controlled kontiki would end up further along the beach compared to our standard Seahorse.

We then looked at using just a GPS unit, but there was no easy way of telling it where to go. A GPS unit only knows where it is, and cannot tell what way it is pointing We found it was difficult to set a course, but once launched, it kept track of itself and kept the Kontiki on course.

We finally decided to combine the two, and use the strengths of each approach. We new use the compass to find and fix the bearing or course you want your Kontiki to follow, and we just the GPS technology to track the Kontiki's progress along this course, and instruct the rudder to turn to keep everything on course.

When then developed the system so you can use it on any beach in the world and it will go where you point it. No-one else can do this.

OPERATING THE GPS AUTOPILOT CONTROLS

There was a lot of hard work and money spent to make the autopilot function as easy as possible to operate. Simply place the GPS Seahorse Kontiki on the beach, pointing in the direction you wish it to travel. There is no need to adjust or allow for side currents, as the GPS Seahorse will do that for you. Ensure the GPS Seahorse is clear of the winch, and motor vehicles, to ensure the electronic compass is not effected. Plug in your batteries and attach your line. The GPS control unit takes between 5 to 30 seconds to get a lock on the satellites, followed by another 3 seconds to get a solid bearing lock. From this controller, calculates the way-point the kontiki will steer towards, and it also will show the 2 lights indicating the course is ready to be locked in. At this stage you can lock the course in by swiping the magnet over the sensor, or if needed, the kontiki can be moved to a new heading. If moved, the control panel will return to a single light, showing the autopilot is getting a lock on the new heading, and after 3 seconds the 2 lights will indicate the course is calculated and ready for you to lock into place.

You can now set the time on the motor controller and launch the GPS Kontiki after the motor has been started.

RELIABLE, SMART ELECTRICS

The Seahorse Electronic motor Control Unit and the Autopilot control unit is completely sealed in resin. This resin block is fitted into the polyethylene body, and is held in place with moulded anchor points. The electronics remove a mass of wiring allowing a clean and simple battery comparent. There are two connecting leads showing to attach the two batteries.

On the motor control unit, a row of 10 super bright LEDs, which shine through the body, indicates your battery status and will indicate if the batteries need charging. The LED lights show the pre-selected running time of your Seahorse. The amount of time is indicated by the number of LED lights which illuminate in a bar display. Once the time is set simply start the Seahorse motor by putting the magnet near the START switch. You can run the Seahorse until the low battery cut-out switches it off, or you can set the timer to 25, 20, 15, 10 or 5 minutes run time.

The LED light flashes fast to show the motor is running, and on the Seahorse 46 the lights will flash slow to show when slow speed is selected.

The Seahorse Kontiki's are the only Kontiki's with built-in automatic stall protection system. If the motor is stalled, the control unit will automatically stop and start the motor up to 3 times trying to dislodge the offending item. - an essential feature for shingle beaches.