Most sailors use their boats primarily at the weekend or for holidays, which partially explains the rapid spread of electric autopilots. Power consumption is not really an issue on one-day trips and the quality of steering performance is also relatively unimportant since it is always possible to steer by hand if necessary. Sea conditions rarely impair steering quality as the majority of weekend sailors do not venture into exposed waters. Taking the helm in any case forms part of the fun for the average sailor, so the autopilot is really just a convenience. It sees to the tedious work (steering while under engine) and gives the crew the freedom to eat together, for example. Autopilots, at least the cockpit models, are also within the financial reach of the average sailor.
The significance of a yacht's autopilot grows with the length of the voyage. There will generally be no problem finding volunteers to steer on a shorter trip, but on a longer trip manual steering becomes tedious and the autopilot will eventually be called into action. The average weekend and holiday sailor has a good autopilot but makes relatively little use of it.
Autohelm has devoted far more effort to the weekend and holiday sector than any other manufacturer and is the world-wide market leader; thanks in particular to its cockpit-mounted range, the company has captured around 90% of the market.
Coastal sailing in unprotected waters normally involves longer voyages. A small crew soon tires of steering and it is here that the steering quality of the autopilot starts to matter. Sea state and factors such as tidal streams, shallows, narrow channels and winds from forward of the beam all impair the performance of autopilots. Rough seas make life difficult for them and as the waves increase in height and frequency the limits of a particular system quickly become apparent. Not surprisingly, intelligent and adaptive systems cope better with trying conditions than factory-set units that cannot be adjusted.
The general standard of equipment in this type of sailing is very high. The importance of good steering performance means that powerful inboard pilots connected directly to the main rudder are much more common; underpowered systems are soon exposed on the open sea. Although more powerful autopilots are inevitably hungrier, this rarely leads to battery problems since coastal sailing includes fairly regular motoring.
An autopilot stands or falls on its blue water performance. An underpowered system on the ocean reacts too slowly, too weakly and with too much delay to keep the boat on course, with increased yawing the result. The fear of losing steerage, of rounding up into the wind or worse and damaging the rig or boat, gives every sailor nightmares. If your autopilot is untrustworthy in a sea you could find yourself at the helm for a very long time.
The choice of autopilot becomes a survival issue for short-, double- or singlehanded sailing: a thousand miles at sea is more than enough to reveal the gulf between theory and reality, and choosing the wrong system could jeopardise the whole voyage. This is evidenced by the large number of would-be passage sailors who, reminded of the enormous importance of good self-steering on the initial leg of their voyage, stop off at Vilamoura, Gibraltar or Las Palmas to fit back-up systems, buy spare parts or add a windvane gear to supplement their autopilot. It is no coincidence that companies like Hydrovane and Windpilot deliver so many of their windvane steering systems to these strategic European jumping-off points!
Although autopilots are standard on blue water yachts, the limitations of the different models (underpowered system, mechanical failures) dictate that they do not in fact steer continuously. A certain amount of manual steering is therefore unavoidable, something that is not always pleasant for the person on watch and that disrupts life aboard. The performance of electric autopilots drops sharply as wind and waves increase, so heavy weather steering often falls to a human helm as well. He or she of course has the advantage of being able to see (and hopefully avoid!) breaking waves.
Jimmy Cornell, organiser of races for long-distance recreational sailors, established in his debriefing after the EUROPA 92 round the world race that automatic systems steered for only 50% of the total time at sea. Manual steering was preferred the rest of time, either to improve speed and carry more sail area or because self-steering systems just were not able to cope with the conditions. Some crews simply did not trust their technology. Almost all the skippers used the autopilot when motoring through calms even if they chose to steer by hand when there was enough wind to sail.
The combination of off-the-wind sailing and long following seas characteristic of blue water passage making sets the stiffest challenge to any autopilot. The need for quick and forceful corrective rudder movements drives up the pilot's power consumption and saps away at the vessel's energy budget. This once again highlights the fundamental importance of responsible energy planning for any vessel intending to rely solely on an autopilot. The average power consumption of the autopilots used in the EUROPA 92 race was approximately 4.9Ah (average boat length 15-18m/ 42-50 ft).
We must add at this juncture that the electromechanical reliability of autopilot systems still leaves something to be desired, particularly under the conditions likely in blue water sailing. This means in practical terms that sooner or later every autopilot is going to fail completely and manual steering will be unavoidable. The American Seven Seas Cruising Association (SSCA) reported following a recent owner survey that the average autopilot serves for about 300 hours before failing. A major study in America found that autopilots normally have useful life of about five years before they have to be replaced. This means that in the US alone thousands of units expire every year, a sobering thought even though the survey does include sail, power and fishing boats. The prospective blue water sailor should find one look at the list in the Las Palmas ARC office of the skippers requesting autopilot repairs enough to trigger deep concern.
Not surprisingly, bigger electric circuits with a larger number of components are more susceptible to gremlins, and the failure of a single, tiny component can be enough in some cases to cripple a whole system. Moisture is another challenge: conditions aboard are always damp, even below deck, and some units are not as waterproof as they could be. Overheating can lead to problems as well. Autohelm's choice of black for its cockpit autopilots is particularly problematic in tropical climes since the colour causes thermally-induced operating temperatures to rise to the point where faults can occur. The sailor's only remedy here is a tin of white paint!
It is striking that those who live aboard their boats tend to revert in the end to the most basic level of equipment, dispensing with any unnecessary gear and reducing clutter aboard; that a good self-steering system still merits a place underlines its importance. One-time pharmacist Lorenz Findeisen has been roving the Caribbean with his Westerly 39 for years. His answer to the question of how his level of equipment has evolved was as follows: "Most of it broke a long time ago, but I'm not really bothered. As long as the anchor tackle, cooker and my windvane gear keep going I can carry on sailing."
Autohelm is the market leader for inboard autopilots. Robertson has considerable experience as a system supplier for merchant vessels and is probably second. B&G, which concentrates mainly on precision transducers for racing boats, supplies quite a few of its NETWORK and HYDRA 2 systems to boats in this sector.
For our purposes races fall into two categories: 1 Fully crewed boats
These are nearly always steered by hand. This applies in all races, from round-the-buoys to the most famous of all, the Whitbread Round The World Race. Whitbread boats and others for the same kind of racing are extreme in all respects: extreme in their ultralight construction (ultralight displacement boats or ULDBs) which allows them to surf at great speed; extreme in their rigs, which are oversized and infinitely tweakable; and extreme in their aim of constantly maintaining absolute maximum speed. Extreme racing is an exhausting sport which pushes crews to their limit and, in the biggest races where expectant sponsors demand success and publicity, often beyond. When autopilots are used on boats of this nature (on delivery passages, for example), only computerised systems with 'intelligent' steering measure up (e.g. B&G Hydra/Hercules, Autohelm 6000/7000, Robertson AP 300 X).
Start of the Vendée Globe in November 1992
2: ULDBs in singlehanded races
Competitors in the Vendée Globe, the singlehanded non-stop sprint around the world which starts from Les Sables d'Olonne in France every four years, rely exclusively on electric autopilots. The race, which includes 50 and 60-foot classes, is viewed by autopilot manufacturers as the ultimate test; the harshest conditions are guaranteed and the use of windvane steering systems is virtually out of the question (see Ocean racing section). Some older, slower vessels in the BOC Race (singlehanded around the world in stages) carry windvane steering systems as back-up, but here too autopilots do most of the steering.
60 ft ULDB Charente Maritime
ULDBs, which rarely have any kind of engine, rely on generators, solar cells or wind generators to maintain the power supply. The boats can reach speeds of 25 knots, so only the most powerful, 'intelligent' computerised systems are strong and fast enough to keep them on course. Autopilots are installed on every boat and steer most of the time. Although competitors in the long singlehanded races tend to follow a
10 minute waking/sleeping cycle, they never for one moment stop thinking about safety and boat speed. Nandor Fa lost about 12 kg in one Vendée Globe and knows only too well how the effects of this kind of deprivation endure.
Autohelm has a very big presence on the extreme sailing scene. The company has devoted particular attention to this area and has earned its success by maintaining a continuous presence before, during and after races, by making considerable service efforts and by cultivating its close relationship with the participants.
Cockpit autopilots lose effectiveness rather quickly as the size of the vessel increases. The manufacturers specify their most powerful models for boats no heavier than 9 tonnes and even this can seem optimistic in more taxing operating conditions. Cockpit autopilots also become relatively power-hungry at higher loads and it is therefore unwise to select a unit for which the boat in question presents the very limit of the rated operating range.
The chief decision with regard to inboard autopilots is the type of drive unit to install. The choice between mechanical linear, hydraulic linear and hydraulic drives depends essentially on:
- Boat size
- Existing main rudder steering arrangement
- Capacity of batteries
- Intended use
Although mechanical linear drives draw less current and are often more convenient for smaller boats, they tend to lack sufficient power for boats of 12 m / 40 ft or more. Hydraulic linear drives are better for bigger boats with their higher rudder loads and larger battery banks. So hydraulic drives are well suited for boats with hydraulic main steering, and a continuously running hydraulic pump is the best option for maxis and bigger.
The autopilot operating speed necessary to keep a particular boat on track has to be calculated. Long keel, long distance cruising boats can manage with a powerful boat more slowly operation system; about 5-6° of rudder movement per second (no load) will generally suffice. A light-built 30 footer with a fin keel and a balanced rudder will need something like 15-20° (no load) but the force applied at the rudder will never have to be very high.
Yacht owners will normally require the manufacturer's help to calculate the specific needs of their particular boat. A high level of support and service from a manufacturer at this point bodes well and will inevitably help to win over an owner. For power boaters who rarely take their vessels beyond the reach of service mechanics, the consequences of an error of judgement at the decision stage are frustration and annoyance. For a blue water sailor they can be disastrous: days on end at the helm with no relief.
A final consideration when choosing an autopilot, and one which you ignore at your peril, is comfort below deck. A noisy drive unit can make an otherwise desirable cabin almost uninhabitable.
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