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CONSIDERATIONS - Autopilots and Mechanical Self Steering

"Ask long-distance sailors what piece of boating equipment they value most and odds are they’ll all say their self-steering gear." - Paul and Sheryl Shard, authors of the best-selling book Sail Away! A Guide to Outfitting and Provisioning for Cruising, and producers of award-winning videos including Cruising the Bahamas and Transatlantic Crossing - found on their www.sailnet.com website.

RENAISSANCE IN SELF STEERING – Powered by the Wind and Steered by the Wind

With the advent of autopilots it was felt that the demise of the older mechanical self steering systems was only a matter of time. But it is now apparent that is not to be – they both have their place. Especially for ocean passages, you cannot beat the quiet simplicity of self steering. Even more compelling is the symmetry of the boat being powered by the wind and steered by the wind.

The autopilot is a wonderful device. It is the only solution for motoring and very adequate for short trips. A mechanical self steering device is the ideal solution for long passages.

DISADVANTAGES OF HAVING ONLY AN AUTOPILOT

• Dependence on electricity –failure of any one of thousands of parts can render an autopilot useless.
• Autopilots cannot run forever – break-downs are inevitable
• Magnetic course is not good enough - The wind direction is never constant. When sailing, the course should always be the same angle to the wind – requires a wind sensor not a magnetic course.
• Challenged in heavy weather - not fast enough, always catching up, increased probability of break-downs
• Hand steering is not an acceptable back-up for a short-handed exhausted crew.

ADVANTAGES OF SELF STEERING

• No worry of break-downs that can render the autopilot useless
• Major reduction in use of electricity
• Solves much of heavy weather steering challenges
• Steers a better course to the wind
• Peaceful and quiet operation of self steering - no motors or engines
• Security of steerage –creates confidence in the boat's equipment

A STORY – told to us by George Day of Bluewater Sailing Magazine

Smaller Boats with Self Steering Beat Bigger Boat with Only an Autopilot

Self Steering Systems Steer a Better Course - Always Trim to the Wind

Three boats left Fiji together all heading to New Zealand – 35, 45 and 55 footers. The smaller two had self steering but not the big boat which depended on its autopilot. The course was mostly to weather.  

The smaller boats beat the larger boat by a considerable margin because of their self steering. The reason is that the self steering systems allowed those boats to hug the wind, always keeping their sails trim – optimizing both their sail trim and course.

With an autopilot the big boat had to keep falling off its course in order to keep its sails full – to avoid being headed.

At the dock or at an airfield watch the Windex at the masthead or windsock at the end of a runway. They are constantly changing direction – even minute to minute - and it only becomes more dramatic over longer periods of time. The wind direction is constantly in flux. If the course of those three boats could be plotted second by second the result would show the course of the boats with self steering looking akin to a plotting of the stock market – very jagged with considerable overall diversion in direction. Whereas, the autopilot generates a virtual straight line course – which one might assume is shorter and faster – but not so. The big boat was hardly ever in trim – almost always untrimmed, sailing inefficiently – neither optimising its sails nor its course. Conversely, the boats with self steering, although sailing ‘all over the place’ they fully exploited their sail trim keeping their boats precisely at the same direction to the wind – optimizing boat speed and achieving the best possible course. (Another example of the superior speed of self steering over autopilots see Tony Gouch's website story "Windvane vs. Autopilot" - http://www.taonui.com/ )

NOTE – Many autopilots do have a wind sensor option which would solve the above issue – subject to any positioning and electronic issues. For whatever reasons, not many wind sensors are sold for autopilots.

WHY SHOULD I CHOOSE A HYDROVANE OVER A SERVO PENDULUM SYSTEM?

All self steering systems sold today are tried and proven. The Hydrovane is one of the most expensive – 25% to 40% more than good servo pendulums. Here are some of the reasons why:

• A unique completely 'user friendly'system - easier to operate than other systems
• No unwieldy lines in the cockpit- just 'click' into gear - noconstant attention to lines, adjusting and re-tensioning
• Emergency steering and rudder system – fully operational ‘ready to go’ and so much better than other systems
• Reliability – virtually unbreakable
• Unmatched course control - only system able to adjust power and sensitivity - can 'straighten your wake'
• Naturally stable with fixed main rudder - less yaw, more comfortable, faster and safer
• Heavy weather mode - Reduced yaw, immediate course correction - better boat motion, shorter passages
• Superior in light airs downwind - due to so little friction in the system
• Normally used 100% of the time when sailing
• Elegant, clean profile - permits use of davits, boarding ladders,swim platformsetc.
• Flexibility in positioning of brackets - no critical location requirements – simple to install
• Can be installed 'off center' - to accommodate boarding ladders, swim platforms etc.
• Suitable for situations that are difficult or impossible for other systems: off centre, hydraulic steering, external rudders, centre cockpits and stiff steering, some slower multihulls
• Unlike servo pendulums - can be used in tandem with autopilot on main steering - helpful in storms, convenient for sail changes or even when engaging and disengaging the HYDROVANE.
• Negligible maintenance and virtually indestructible

REPORTS FROM THOSE THAT SWITCH FROM A SERVO PENDULUM SYSTEM TO A HYDROVANE

Those that have switched to a Hydrovane - were happy enough with their servo pendulum systems but wanted to get the lines out of their cockpits with the bonus of knowing they have an effective back up steering system. Once they have experienced the Hydrovane they report to us:

• The pleasure in no longer having those lines in the cockpit.
• Surprise at how easy it is to engage and disengage - remembering the hassle of tensioning and fiddling with those lines.
• "Magical" they say about its performance downwind in light airs.
• No regrets - nothing lost in performance
• Confidence and comfort in knowing that a back-up steering system is in place

EMBELLISHING ON HYDROVANE'S PERFORMANCE

Once engaged a servo pendulum system does its work without any means of tuning or straightening its course. In a flat sea it creates a ‘snake wake’ – as does an autopilot or human or a Hydrovane. But, the difference is that a Hydrovane can be tuned to straighten that wake to within a few degrees of a perfect course in a calm sea but far more importantly is the significant reduction of yaw in a heavy sea because:

• NATURAL STABILITY - Only with the main rudder fixed can the boat be stable in a bad sea. You can imagine the stability produced by having the main rudder fixed in its balancing direction.
• SENSITIVTY ADJUSTMENT - The vane axis can be set in a position that greatly tempers the response of the vane. The vane is the sensor that triggers all activity. The Hydrovane vane can be adjusted from avertical position to up to thirty degrees off vertical. That adjustment does not sound like much but what it does is dramatic. It changes the physics of the transmission of the sensory instruction from the vane to the delivery system that turns the rudder.In comparison all servo pendulum systems lack this adjustability for sensitivity and are set at a fixed axis setting - no ability to adjust for sensitivity. Hopefully we shall see you at a boat show someday where we can demonstrate to you this major affect.
• RUDDER SETTINGS – The Hydrovane has three different settings for the degree of rudder angle - can change amount of steerage applied.

The natural stability of the fixed main rudder combined with the unique ability to tune the system for sensitivity and steerage sets Hydrovane apart.

HYDROVANE IS SOPHISTICATED - with ease, it gives a more comfortable ride:

• More direct course - faster
• Calmer - less yaw
• ...safer!

I TOO HAVE HEARD THAT SERVO PENDULUM SYSTEMS ARE MORE POWERFUL THAN THE HYDROVANE. IS THAT TRUE?

You have probably also heard “the harder it blows, the better it works” which is true – but also true is the converse which is implied: in lighter winds it could have problems. A servo pendulum does generate a lot of power - but only when the boat is moving quickly through the water. When moving slowly it is deficient in power - a condition that is worsened if there is any excess friction in the system - stiff rudder, arduous connecting lines etc. It can produce wonderful performance in all conditions on some boats - but not all.

We have too often heard owners of servo pendulums that are very proud of their units but advise that when off the wind they only work in a minimum of 15 or 20 knots of wind – not all, but some!! See our comments elsewhere on the ideal application of a servo pendulum system - high friction systems have significant weaknesses.

In comparison with a Hydrovane this power issue only becomes relevant for larger boats as the Hydrovane system is more than adequate for lighter boats. We suggest maximums of 40,000 lbs. or 18,000 kgs. for the Hydrovane - and always happy to tell you about many 50,000 lb. or 23,000 kg. boats that also have glowing reports about the performance of their Hydrovanes – having adapted to its limitations – see section on Oversize Boats. The Hydrovane’s power is limited to the size of its rudder and the speed of that rudder through the water. As explained above it is a more efficient system than the servo pendulum systems but it can only do so much. The question is whether a servo pendulum would outperform a Hydrovane on your boat - and in what conditions?

If you have ever had the chance to see a servo pendulum operating in bad weather you would better appreciate where that comment about its power comes from. Its activity can be described as perhaps violent as it wrenches the wheel/tiller from one course to the next. One certainly wants to stay clear of that section of the cockpit. We do suggest that there is some overkill in that performance – due to over steering or under steering - servo systems are fairly rigid in the amount of steering applied - not tempered to the conditions. On those same boats if they had a Hydrovane the demonstration would not appear so spectacular – but if you did stick you head over the stern you would marvel. The comparison is like the difference between the less skilled hard working rookie and a skilled athlete that makes a play look so easy as the Hydrovane rudder nimbly flops back and forth with immediate response to dramatic course changes but confidently not over-reacting to the ‘fakes’ that would have fooled a human helmsman. I know that this simile is a little too generous – but you get the point.

If your boat is over 40,000 lbs or 18,000 kg. you should consider the pros and cons of the two systems. If your steering system is at all stiff or the rudder is not balanced you will find that a servo pendulum will certainly impress you in heavy weather - at least it better impress as it could disappoint in lighter airs. A big boat with a system that is only good off the wind in 20 knots + means so little usage ….. and too much of the autopilot. If the Hydrovane has a shortage of power in challenging conditions the remedy is more conservative sailing - a bit less sail - but better course travelled, more comfortable....and probably no slower - just not such an aggressive ride.

Our customers with larger boats who have had experience with both systems have a hard time in comparing the heavy weather performance – as it is all so difficult in those conditions and they would have adapted the steering system to the conditions – meaning that if the Hydrovane was being overwhelmed they would make appropriate adjustments as they would with a servo pendulum.

For big boats the ideal application for a servo pendulum system is like the boats used by long distance solo racers: a balanced spade rudder on a balanced boat that is steered by a tiller that is located near the transom - the tiller should be so light to the touch, even in bad conditions. In that configuration a servo pendulum is at its best.

• Power is only an issue for larger or faster boats
• Many boats are not ideal applications for a servo pendulum
• Hard to compare power in heavy weather - the elements produce such opposition – technique is to de-power the vessel so that the steering system can manage
• Hydrovane system is more efficient in its use of power
• Be wary of acquiring a system for its power and suffering inadequate performance in normal and lighter conditions

CAN A HYDROVANE FUNCTION IN TANDEM WITH AN AUTOPILOT ON THE MAIN RUDDER - BOTH ON/ENGAGED AT THE SAME TIME?

Most certainly. That is a feature of only auxiliary rudder systems - and is such a convenience! In situations of fast changing weather conditions or even the simple process of engaging and disengaging the HYDROVANE an easy management technique is to click on the autopilot. Once sails have been adjusted and control achieved then the autopilot can be turned off. Finally you take the wheel or tiller and find that ‘sweet spot’ or position to locked it off. It is that simple.

In major storms many have used this technique when the Hydrovane appears to be challenged to the maximum and needs all the help it can get. That is often the case in the early hours of a storm when the seas are square and chaotic. Once the storm has blown for a while and the seas become more regular then the autopilot can be turned off. Incidentally, the HYDROVANE is proven to be quite capable of steering the boat in very high winds.

This technique is also ideal for the aggressive sailors – for surfing conditions – to compensate for rapid changes in apparent wind direction. Many set the autopilot to respond only for course deviations greater than 10 degrees or more - so the autopilot is dormant most of the time and only activates when needed.

• Unlike non auxiliary rudder systems a HYDROVANE and an autopilot easily function in tandem/together
• When used in tandem each helps the other – in total, enormous steerage power – or less work for each
• The autopilot is set for 'Low Gain' - only activates when the boat is well off course
• Ideal for dramatic weather changes requiring major sail adjustment
• Many use this technique even for engaging and disengaging the HYDROVANE
• Comforting to use in storms when uncertain – can turn off once control is regained
• Ideal for aggressive sailors in surfing conditions or to be safe when carrying too much sail - set for course deviation of greater thanten degrees

Note - This technique is not to be confused with retrofitting a tiller style autopilot onto the HYDROVANE. That is an entirely different feature. To clarify - thistandem function involvesthe engaging of the main autopilot that operates the main rudder while, at the same time the HYDROVANE is also engaged and operating - two rudders are better than one.

IF MY BOAT IS LARGER THAN THE RECOMMENDED LIMITS AND I DID INSTALL A HYDROVANE WHAT KIND OF PERFORMANCE CAN I EXPECT?

The Hydrovane only delivers its certain amount of steering. For heavier or faster boats its abilities diminish with weight and speed. Speed is the bigger determinant with the yellow/warning zone at 8 to 10 knots and the red zone anything above that. In 2006 we introduced a bigger rudder and since then have been improving the balance of that rudder. The Hydrovane system is now more capable of handling bigger and faster boats. We too would like to know where the saw-offs are.

We do know of many boats in the 25 ton (23,000 kg.) range that are pleased enough with their Hydrovanes – and theirs are all with the old smaller rudder. They are ideal candidates to upgrade to the new rudder for improved performance.

Generally, we can say that bigger boats would probably find a HYDROVANE could steer their vessels at least ‘most of the time’ if not ‘all of the time’ – subject to the ‘balance’ of the boat. If the vessel is losing control then the solution is to re-visit the trim of the sails or maybe ease off the sheets or probably reduce sail. That is the compromise – speed. Of course, the more ‘balanced’ the boat is the more sail it can keep up.

Another technique that is only possible with an auxiliary rudder system is to use your autopilot simultaneously/in tandem with the HYDROVANE. Yes, with the HYDROVANE engaged you may also turn on the autopilot on the main steering system – then you will have two rudders steering the boat instead of one – tremendous steering power. This is helpful for big boats in a storm when there is concern whether the Hydrovane can handle the job. Once sails have been adjusted and control regained or the storm settles down, the autopilot can be turned off. This technique is also useful for normal operations like engaging and disengaging the Hydrovane or when making sail changes.

Finally, the other major reason to have a HYDROVANE is the back-up/emergency rudder and steering system. No matter how large the boat a HYDROVANE rudder and its overbuilt structure would be quite capable of getting any cruising yacht safely back to port. The importance of a boat having steerage is second only to its ability to float.

• Should function, at the minimum, most of the time
• Sail more conservatively, probably more comfortably, perhaps a bit less speed
• When challenged, can employ the autopilot to run in tandem/simultaneously with windvane
• Have a truly reliable, 'ready to go' back-up emergency rudder and steering system

We suggest maximums of 40,000 lbs. (18,000kgs.) or 50 ft. ( 15m.) but know of and even provide many installations for boats in excess of those limits. In each case the customer must help gauge the suitability. At the minimum they will get an emergency steering system – the Hydrovane’s trump card!

No matter how 'improved' autopilots become the role of a mechanical self steering for an offshore cruiser will always be the primary workhorse of the extended passage. It is your best crew: tireless, dependable and quiet...and it requires no electricity.

COMPARISON HYDROVANE VERSUS SERVO PENDULUM SYSTEMS