Sailing straight ahead is not difficult. However, it is not without reason that the helm is often handed over to the owner or skipper during harbour manoeuvres, as this requires skill and concentration. If wind and current also come into play, even the skipper sometimes starts to sweat.
To make mooring a little more relaxed, at least in the home port, many owners are very inventive when it comes to optimising their box. Be it by cutting the mooring lines to the right length, mounting fenders firmly on the bow and sides - or even by fitting the box with a system of V-shaped mooring lines into which you only have to steam slowly when mooring, so that you come to rest at a good distance from the jetty.
Over the past few decades, countless patents have been filed for aids designed to make mooring easier. But nothing is more pleasant than being able to simply hand over command to an experienced helmsman as soon as things get dicey.
In times of assistance systems in air and road traffic and research into autonomous driving, it was therefore only a matter of time before the marine industry would bring a system onto the market that would completely take the worry out of mooring.
Practically a virtual helmsman who, with watchful eyes and experienced hands, skilfully steers the ship to the pier. Even if no provider has yet developed a ready-made system that is sold in series or can even be taken from yacht to yacht, two providers have already presented systems that manoeuvre the ship cleanly to the jetty.
In BOOTE 8/19, we already reported on our experiences with the Docksense system from Raymarine. The Volvo docking system even controls the mooring manoeuvre completely autonomously.
Prerequisites
Two things are necessary for a ship to be able to dock automatically: firstly, the steering computer must recognise its position and surroundings with the help of GPS, cameras and sensors in order to detect obstacles and find its way to its destination.
Once the environment has been recognised, a second system takes over control of the ship by accessing the throttle and the steering.
A joystick control system is required as the basis, which is either coupled with two rotating engines (IPS, Z-drive, outboard motor) or alternatively with an engine with a fixed shaft and bow/stern thruster.
thruster. The IPS drives from Volvo are very sophisticated and well-established.
After activating the joystick, the drives react computer-controlled to every movement, turning together or in opposite directions, accelerating forwards or backwards. In this way, the ship can be rotated around its own axis, held on the spot or even moved sideways, intuitively and with centimetre precision using both motors: If the skipper pushes the joystick to starboard, one engine pushes the stern of the boat towards the jetty.
The gyro within the course computer immediately recognises that the boat wants to initiate a turning movement, whereupon the course computer uses the propeller of the other engine by moving forwards and backwards to prevent the boat from turning or moving forwards. Instead, it keeps the bow pointing in the same direction.
While a lot of screw water foams up the harbour basin on the port side, the ship moves slowly and directly sideways towards the jetty.
Reach your destination with the joystick
The outboard engine manufacturers Mercury, Yamaha and Evinrude have similar joystick control systems in their range, as does the gear manufacturer Seastar with its multi-compatible Optimus 360 solution for modernising older boats. Here too, once activated, the outboard motors fold outwards individually by up to
up to 30 degrees outwards so that the propeller current can be channelled forwards or backwards in a diagonal direction under the boat.
In this way, as with the Volvo IPS system, it can be manoeuvred completely freely in two dimensions with both engines. The joystick controls for outboards also have a "virtual anchor". The brand's own designations "Skyhook", "Set Point" or "Stay" describe the function with which the boat is held in place under GPS control.
It also feels good to be able to simply let go of the joystick when things get too dicey, and the ship simply stops in position, as if you were putting the brakes on when parking your car and thinking about your next steps.
A privilege that was previously denied to boaters due to crosswinds and the drifting of the boat.
In the USA, this mode is often used when fishing in tidal areas so that nobody has to actively hold the boat in place. With some systems, the position holding mode can also be combined with the course holding function, for example to keep the bow in the waves.
But the function is also very helpful when mooring: if the skipper needs to have his hands free to prepare lines and fenders, the boat keeps itself in position and is not embarrassed to drift.
Raymarine combines all of these functions in its docking system: Docksense not only ensures that the boat can be manoeuvred precisely into the box with the joystick after taking control, but also that it simply holds its position when the joystick is "released". In addition, a virtual fender about one metre wide surrounds the entire boat and prevents other ships or obstacles from getting too close to the boat.
During harbour manoeuvres, the system even stops the ship's speed in good time so that the virtual fender is not "flattened", or initiates evasive manoeuvres on its own in dicey situations. With the new docking system, the two invisible influences of crosswind and countercurrent no longer pose a danger either, as it recognises a drift at an early stage and counteracts it.
Semi-automatic
Transferred to the image of the virtual helmsman, a total of five FLIR stereo cameras mounted around the ship represent the eyes on board the Prestige 460 tested in BOOTE 8/19. Two at the front, two on the sides and one at the stern. The FLIR cameras were actually developed for use in shopping centres to count customers. With two different viewing angles, they perceive the surroundings in three dimensions, detect objects that are at least 40 centimetres above the water and track their movements in relation to the ship.
As the cameras are not inherently waterproof, they were mounted in a bulky housing, the cover of which opens automatically during manoeuvres and closes when not in use. When Docksense becomes established, it is to be expected that the "surface mounting" will give way and the cameras will be integrated into the deck mould. The five camera images are displayed on the plotter. The course computer also calculates a top view of the surroundings.
Docking is now semi-automatic: the skipper activates the system, but then has to move the boat to the desired berth independently using the joystick. However, the boat is actually easier to steer because Docksense keeps the bow of the boat pointing in the initial direction and uses the fender to ensure that it doesn't hit anything when mooring.
However, the boat's reactions are slower than with the usual IPS joystick control. It is also unusual for the experienced skipper to keep the joystick fully pulled until the boat is moored to the jetty when reversing in the box, and not to reduce the pull on the joystick as the jetty approaches. Align the stern with the box, pull the joystick - done.
Once the boat is in the box, the diameter of the virtual fender can be reduced so that you can get closer to the jetty and the crew can easily get off the boat and moor it. The system is also so intelligent that it cannot be distracted during manoeuvring, for example by a line thrown to the boat.
Docksense can be installed on any boat that has a joystick control. To make it compatible with all manufacturers of such controls, Docksense is also activated on the plotter and not on the joystick.
However, the system is only available as standard on a few yachts and, at 25,000 euros, is not really cheap due to the amount of technology involved.
Fully automatic
The only system that brings the yacht to the dock completely independently is the docking system from Volvo Penta. However, unlike Docksense, which recognises the surroundings, it is necessary to equip the home box with sensors.
As the ship approaches the box, the system recognises its proximity to home and sends a message to the skipper that it is ready to dock.
Similar to a robot hoover, which aims for its home base when the battery is empty and drives to the charging station, the ship also aims for the transmitters on the jetty in order to orientate itself and steer precisely into the box.
The system already works relatively accurately, as a press presentation by Volvo Penta in Gothenburg showed.
However, it does not make life much easier for amateur skippers if the system is only able to call at their own box. This is because it is useless on a summer trip from harbour to harbour, and the owner is hardly any further ahead than the motorboat drivers of the past, who equipped their boxes with mooring lines.
When mooring, the docking system also keeps the boat in place with the help of the dock transmitters and GPS. However, Docksense claims to be accurate to 0.5 metres, whereas Volvo is only accurate to 2 metres, which can be quite a lot of inaccuracy in a box. Mooring the ship is then once again the crew's job - although there are already developments here too, such as the Cleatline (cleatline.com), a robotic arm remotely controlled from the helm that grabs the cleat and clings to it.
So far, these systems are not yet compatible with Docksense or the Volvo docking system. And that's probably a good thing - after all, you have to do something on board yourself.
