Operating principle of current Wind Vane Steering equipment
A Wind Vane Self Steering device is one which employs mechanical and hydro-mechanical principles in order to maintain a yacht on a constant course in relation to the wind direction.
Wind-Vane self steering equipment has many advantages over electric autopilots:
- It does not require electrical energy for its operation.
- It can be used in all conditions, even in strong winds.
- Its simple construction allows repairs to be made with on-board tools.
- The sails keep their trim even in variable wind conditions.
- It is quiet in operation.
All present-day Vane Steering gears use the same operating principles. A windvane reacts to changes in the apparent wind direction and transmits this reaction to the servo pendulum in the water which, in turn, operates the boat’s steering or an auxiliary rudder.
The windvane itself does not possess sufficient power to steer the boat, this is augmented by the servo pendulum. The energy required for this is generated by the forward motion of the boat, through the flow of the water along the submerged portion of the servo pendulum. The connection between the wind-vane and the servo pendulum is through struts or a gear train.
Wind-vane steering equipment must satisfy a number of requirements:
- Sensitivity on all courses even with light following winds
- Sufficient power for the rudder configuration
- Precise steering through course corrections proportional to the variations in wind direction
- Absence of over correction which would result in a zigzag course
Beaufort® Windvane Self-steering Systems
In order to satisfy all these requirements we employ:
- A wind vane operating on an inclined axis in order to improve reaction to changes in the apparent wind.
- A submerged servo pendulum acting on the rudder.
- Struts connecting the wind vane and the servo pendulum. This simple and robust solution minimises weight and inertia, a significant advantage over connections using gear trains.
- Connection between the servo pendulum and the wheel or tiller is via steering lines.
- A minimum of friction, inertia and free play in the entire system.
- Marine quality stainless steel for high corrosion resistance in the salt water environment and black UV resistant Delrin.
► The upper portion of the equipment
The upper portion of the equipment
The upper part of the equipment consists of a very light wind vane which is balanced with a counter weight and is mounted on a vertical carrier. The course relative to the apparent wind is set simply by turning the base on which the wind vane is mounted.
At rest the wind vane is vertical. As soon as the direction of the apparent wind changes this presses on a side of the wind vane which is pushed down to one side. The wind vane moves through a disproportionally greater angle than the alteration in wind direction which gives rise to a considerable multiplication effect in the system. This arrangement is far more efficient than a traditional wind vane mounted on a vertical axis (eg. Haslers Gibb or the Atlantic model of Windpilot. The configuration around an inclined axis used in our systems stems from the trials of Marcel Gianoli on Pen-Duick ll for the 1964 Transat)
► The lower portion of the equipment
The servo pendulum is also an achievement of the 1964 Transat (Blondie Hasler). Our servo pendulum has a hydrodynamic profile and is positioned vertically in the water. It turns about a vertical axis (reaction to the signal) and about a horizontal axis parallel to the longitudinal axis of the boat (multiplying the signal strength – two degrees of freedom).
The declination of the wind vane is transmitted to the vertical axis of the servo pendulum by struts. (The idea of transmitting the turning signal by means of a “Z” originated with Yves Gélinas.)
The vertical rotation of the servo pendulum is proportional to the change in the direction of the apparent wind. The greater the deflection of the servo pendulum about its horizontal axis, the smaller will be the turning angle. This damping effect prevents oversteering which would otherwise result in a zigzag course.
Due to the compensation of the servo pendulum the wind vane requires little power to turn it.
As soon as the servo pendulum is turned about its vertical axis – and the boat has a certain speed through the water – the press of water will act on one side or the other and cause it to swing about its horizontal axis and this movement will be transmitted through the steering lines to the rudder. In the final analysis, it is the flow of water which provides the necessary energy to move the rudder.
The servo pendulum is protected against overload by a catch which disengages in case it collides with a floating object.
The user friendliness of our systems is achieved by:
- Reduced weight
- Solid construction
- Easy mounting
- Simple servicing, if ever required
- Metric fasteners
Delivery of the beaufort ® Wind Vane Self Steering equipment.
We will deliver a complete unit with all necessary items for installing the unit. The satisfactory operation of the self steering system depends largely on the lead of the steering lines which connect the servo pendulum with the rudder. We are happy to offer our advice, the benefit of our experience and the availability of special fittings in order to obtain the very best solution for your particular yacht. Naturally we will be happy to answer any questions regarding fitting and commissioning of the unit.
The inclusions consist of:
- The complete unit
- The struts for fitting the unit to your particular yacht.
- Depending on the model chosen, a servo pendulum of either wood or stainless steel.
- A wind vane of polycarbonate.
- A wind vane for higher wind strengths of marine ply (in order to avoid electrolytic corrosion).
- A schematic drawing and/or photographs detailing the installation.
- Comprehensive instructions for use with a parts list.
Useful Additional Equipment:
In addition to the listed inclusions we offer the following items:
- Single or double turning blocks for the steering lines.
- Turning blocks for the adjusting lines used for setting the wind vane.
- Wheel adapter drum for the steering lines.
- Adapter plate with holes for attaching steering lines to the tiller.
- Pivoted boarding ladder mounted on the frame of the unit
- Swimming platform according to your requirements.