South Atlantic Windvane: F.A.Q & Technical Guide

1. Why is a windvane self-steering system considered essential for offshore sailing?

It is considered essential because it requires no electricity, acts as a reliable "crewmember," and makes life on board easier.

2. Does a South Atlantic windvane require any electrical power to operate?

No, these systems require no electricity to function.

3. What are the primary advantages of using a mechanical windvane over an electronic autopilot for long crossings?

When a ship sails with its sails set, the wind steers it more effectively than an electronic sensor.

4. How long does the average owner-installation typically take for these systems?

Most units are easily owner-installed in only 2 to 4 hours.

5. What is the core principle behind how a windvane senses the boat's course?

Mechanical devices sense the apparent wind direction and steer the boat on a course relative to it.

6. Are South Atlantic gears designed to be simple, robust, and reliable for gale-force conditions?

Yes, they are simple, robust, and reliable self-steering gears built for gale-force conditions.

7. Why is it said that "the wind steers the ship better" when sails are set?

A windvane utilizes the natural force of the wind more efficiently for relative course-keeping than an autopilot.

8. Which model is specifically recommended for the Class Mini 5.80?

The S 301 is the recommended model for the Class Mini 5.80.

9. What is the suitable sailboat length range for the S 301 model?

It is designed for sailboats between 18 ft and 30 ft.

10. For a boat between 24 ft and 40 ft, which two models are primary options?

The South Atlantic S 440 and S 500 are suitable for this range.

11. Which model is designed for larger sailboats ranging from 36 ft to 60 ft?

The S 470 and S 600 model is designed for this size range.

12. Is there a specific model designed for daysailers under 20 feet?

Yes, the South Atlantic Ultralight Windvane is for daysailers under 20 ft.

13. What boat size range is covered by the L 360 model?

It is for sailboats between 18 ft and 24 ft.

14. Which model is described as the strongest and most powerful in the South Atlantic range?

The S 600 is the strongest and most powerful model.

15. Does the S 470 model cover boats up to 60 feet in length?

Yes, the S 470 is suitable for sailboats between 26 ft and 60 ft.

16. How does the rudder shaft move in a servo-pendulum system?

The rudder shaft moves sideways (swing) depending on the vanes' signal and the position of the rudder.

17. Do steering forces in a servo-pendulum system increase or decrease as the wind picks up?

Steering forces increase with both wind speed and vessel speed.

18. What is the maximum ship displacement that a modern servo-pendulum can typically steer safely?

Servo-forces are usually enough to safely sail ships of up to 30 tons.

19. Why is steering through the tiller considered ideal for servo-pendulum transmission?

Proper transmission is indispensable, and steering through the tiller is considered ideal for this system type.

20. Can the pendulum rudder be lifted out of the water when the system is not in use?

Yes, rudders can be lifted out of the water on one side when not in use.

21. Is collision damage protection built into the servo-pendulum designs?

Yes, collision damage protection is built-in.

22. Do servo-pendulum models require steering lines to be connected to the helm?

Yes, steering lines to the helm can clutter the cockpit in these models.

23. Are servo-pendulum systems readily suited for use as an emergency rudder?

No, these types are not readily suited for use as an emergency rudder.

24. How can the windvane mast height be adjusted for different sailboat designs?

The height of the windvane mast can be customized to suit your sailboat design.

25. Are there various lengths available for the servo pendulum shaft?

Yes, the length of the servo pendulum shaft is available in various lengths.

26. What makes the S 500 and S 600 "Ready To Go" as emergency steering systems?

They are designed as a dual-purpose self-steering and emergency rudder system ready for immediate use if the main rudder fails.

27. Why are auxiliary rudders the preferred choice for sailboats with hydraulic steering?

They are the right choice for hydraulic steering because they operate independently of the main steering system.

28. How does the cockpit remain "clutter-free" when using an auxiliary rudder system?

There are no steering lines required in the cockpit for these models.

29. Which system type is more sensitive in light air?

Auxiliary rudders are more sensitive than servo-pendulums in light air.

30. Why do auxiliary rudders offer more steering power than servo-pendulum models?

They offer more power because of the aft position of the rudder.

31. Can the boat's main rudder be locked in place when the auxiliary rudder is steering?

Yes, the main rudder can be locked in place to manage weather helm while the system steers.

32. What is the maximum degree of helm the S 500 or S 600 can apply?

They can put the helm over by 35 degrees.

33. How does the auxiliary rudder compensate for weather helm?

The auxiliary rudder has maximum leverage from its position at the stern to turn the boat.

34. Is the auxiliary rudder and pendulum rudder perfectly matched in the S 500/S 600 design?

Yes, the pendulum and auxiliary rudders are perfectly matched.

35. Why is the aft position of the auxiliary rudder advantageous for leverage?

The extreme aft position provides the maximum leverage for turning the vessel.

36. Can South Atlantic windvanes be customized to fit specific boat requirements?

Yes, all models can be customized.

37. Is it possible to install the gear yourself, or is professional help required?

All units are designed to be easily owner-installed.

38. What materials are used for the fixed mast steps?

They are made of aluminium.

39. How many models are included in the current South Atlantic product range?

The product range consists of 7 models.

40. Does South Atlantic provide a "crush course" for learning how the system works?

Yes, they offer a crush course for more details on system operation.

41. Is the S 600 model considered a dual-purpose system?

Yes, the S 600 is both a self-steering gear and an emergency rudder.

42. Can all, or only some, self steering devices be mounted off-centre?

Self-steering devices can be mounted off-center, but doing so introduces geometric asymmetry that can affect their performance depending on the vessel's heel angle and tack.

43. What happens when a self-steering device is mounted off the vessel's centerline?

When mounted off-centre, a geometric asymmetry is introduced that changes the system's behavior depending on the tack and the vessel's angle of heel. This affects the hydrodynamic flow around the submerged appendages.

44. How does heeling affect an off-centre mounted device?

When the vessel heels away from the side where the device is mounted, the quarter where the device is located rises relative to the local dynamic waterline. This reduces the effective immersion of the blade and brings its lower tip closer to the surface.

45. What is ventilation and why is it a problem?

Ventilation occurs when atmospheric air is drawn down into the low-pressure region around the submerged appendage. This reduces lift and steering effectiveness. Off-centre mounting increases the risk of ventilation, especially when heeling away from the mounted side.

46. How does flow asymmetry affect off-centre installations?

Unlike centerline-mounted devices where flow is generally symmetrical, off-centre installations place the blade in a different hydrodynamic environment. The flow is influenced by the hull's boundary layer, local turbulence, wake structure, and vortices, producing different steering characteristics on port and starboard tacks.

47. What structural effects does off-centre mounting create?

Off-centre mounting introduces an additional transverse lever arm. The hydrodynamic forces generate not only steering torque but also additional loads and moments on the mounting structure. Any elastic deformation or bending of brackets can cause slower steering response, reduced precision, or increased deadband.

48. Are these differences caused by the brand or type of windvane?

No, these are not theoretical differences created by the brand or type of windvane. They are consequences of the geometry of placing a submerged steering surface away from the vessel's centerline.

49. What factors make the geometric effects more significant?

The geometric effects become more significant the further the blade is moved from the centerline and the greater the vessel's heel angle.

50. Since what year has South Atlantic been manufacturing these gears?

We have been manufacturing worldwide since 1987.

51. Are the systems sold directly from the factory?

Yes, we offer worldwide sales factory direct.

52. What percentage of windvane buyers also have an electronic autopilot on board?

Almost 100% of buyers have an autopilot on board before purchasing the windvane.

53. How often is the windvane used compared to the autopilot once both are installed?

The windvane is used 90% of the time after both systems are installed.

54. Does the company offer specialized gears for ultralight boats?

Yes, they offer the "Ultralight" model for daysailers under 20 ft.

55. Where is the South Atlantic Design Office located?

The design office is located in Werther, Germany.

56. How can a customer request a quote or technical information?

Customers can use the provided email addresses, phone number, or the contact form.

57. Does South Atlantic also manufacture mast steps?

Yes, we also produce fixed mast steps and boom brakes.

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