This section of the Navigate-us website is different. Rather than recommending specific Autopilots for your boat type or allowing you to compare them, we provide you with a number of key questions you need to answer. The answer to these questions will enable your Dealer to advise on the key decision about choosing an Autopliot. When you read this section you will see why Navigate-us recommends this approach.
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Selecting the Right Autopilot
Before selecting an autopilot, it is important to know what they really can and can’t do. Let’s start by looking at what an autopilot really does, and then consider how you might use it.
What does an Autopilot Do?
An autopilot, or pilot, as it is often known, has one main function: it takes control of the boat’s steering to control the boat’s heading. The actual heading depends on the function or mode that is running at the time. There are a variety of modes; the most common ones are described below.
Also known as “point and shoot”, this is the simplest mode of operation for any autopilot. The pilot maintains a fixed compass heading and counteracts the effect of wind and waves, and sail trim for a yacht. What it doesn’t do is make any allowance for tide.
Navigation or Track Mode
In this mode the pilot uses data from the chart plotter to keep the boat on a predetermined track line. The pilot is still directly controlling the heading, but the heading is constantly adjusted to keep the boat as close as possible to the track line, and minimize cross track error. This effectively makes allowance for tide and leeway. Modern systems do this very accurately, down to small fractions of a nautical mile. When planning a track to be followed by the pilot, ensure there is sufficient clearance for safe passage past obstacles, especially navigation marks and buoys if these are used as turning points. Do not place your waypoint directly over buoys, as this could pose a risk of collision.
On a yacht, the pilot can use data from the wind instruments to adjust the heading. While this mode can be used for any wind angle, it really comes into its own on either a close fetch, or a broad reach. In the case of a close fetch, it allows the boat to be trimmed closer to the wind than in normal heading mode, thus maximizing VMG to windward. It is difficult to sail a yacht fully close hauled effectively and consistently under pilot, unless the conditions are very stable. For a broad reach, it allows the boat to be sailed deeper, but without the risk of either broaching out or gybing on windshifts.
The pilot can perform a number of preset maneuvers to assist in trolling. The exact patterns vary from manufacturer to manufacturer, but are essentially designed to help troll over a point, such as a wreck, or along a line feature such as a drop off.
How Do I Use an Autopilot?
Let’s consider some of the underlying functions that a pilot can and can’t do, and then we’ll ask some questions about how these might apply to your particular flavor of boating.
First, a word of warning. A glance at any manufacturer’s operation manual will alert you of one main fact: An autopilot is not a substitute for the captain of the vessel, good seamanship and especially good watch keeping. The responsibility for the safety of the vessel remains squarely with the captain, the pilot, may be considered a competent but blind helmsman. If you plot a course that crosses shallow water, takes you into the path of an oncoming ship, or merely through a buoy, then that is where the autopilot will take you, accurately, calmly, and with potentially catastrophic results.
With that in mind, let’s look at some of the really positive aspects of owning a pilot. A well set up pilot really does increase the usefulness and fun of virtually any boat. It makes short handed passages a reality. It is like having another member of crew aboard who is willing to steer the boat, whatever the time, whatever the weather. For those not involved in short handed work, it reduces workload at the helm allowing for increased situational awareness, reduced fatigue, more time looking after the general running of the boat, systems and crew. Without a pilot, it’s virtually impossible to get the best out of the other electronic systems on the boat. It allows you to arrive at your destination, picnic spot or fishing ground fresher and ready to go.
How does this apply to your boating?
The single biggest question that you need to answer honestly and accurately is; “How much will I use my pilot and how crucial will it be me in operating the boat safely and effectively?” Ask yourself, what will I do if the pilot goes wrong?
For example, if you are a couple planning to do some serious blue water cruising, then the pilot will be crucial. It is likely to run 23 hours a day, day in day out. Without it, one of you will be tied to the wheel, seriously reducing the overall crew capacity. Similarly, if you regularly fish several hours offshore, then not having a pilot will seriously reduce you pleasure in running the boat and being able to fish.
Why is this question so important?
It is absolutely crucial to pick an autopilot that is powerful enough to steer your boat effectively, and has the performance to do so in all the conditions you are likely to encounter. These decisions, as usual are all related to budget, cutting short here is almost always false economy. Many people are initially content with the idea that they will occasionally use the pilot, in calm weather to help put the sails up and down. At sea, with the wind rising, and a seasick mate is not the time to discover that you have sold yourself short.
If you really do just go for short coastal hops, and always have plenty of help on board, then it’s perfectly feasible to go for a lighter budget selection—just be honest with yourself before making that commitment.
So, you now know what an autopilot can do, and how you will use it in you particular boating. We will now look at the specific factors to help chose the right size and style of pilot.
Four Crucial Factors in Selecting an Autopilot
There are 4 main factors in selecting an autopilot, and in approximate order of priority they are:
- Weight of the boat
- Performance required
- Type of steering
- Functionality required
Weight (or displacement) is the primary driver for selecting an autopilot. If the pilot is not powerful enough, then it will struggle to do the job, and it won’t last long. A good analogy is to consider the engine in your car: it’s got to be big enough to do the job in hand.
Most manufacturers have displacement bands for their pilots. You often hear the argument “My boat has finger light steering, so I can afford to go down in size”. Actually, if your boat has heavy steering (long keel, unbalanced rudder, heavy displacement hull, too much canvas, etc.) you should consider going up a step. Another crucial factor to consider is that you must use the laden weight of the boat. The difference between unladen and laden weight can be significant, especially if you are loaded up with supplies for an extended passage. All of this leads to one approach: stay on the conservative side of the weight limits for reliability and performance.
The Performance requirement
In general, there is one key decision to make regarding performance: “Should I choose a pilot with a ’rate gyro’”? A rate gyro is a device that senses the boat’s rate of turn. It’s almost like giving the electronic pilot a “seat of the pants” feel. The pilot can sense when the boat is starting to turn off course, even before it has gone off course. The electronics can then react to this with smaller rudder movements than would otherwise be necessary to correct a real course error. The overall result is that the pilot holds course more accurately and more predictably in a wider range of conditions. The gyro really comes into its own in “hard to steer” conditions such as following or quartering seas.
A positive by product of selecting a pilot with a gyro, is that you will have a more stable and accurate heading sensor than relying solely on the fluxgate compass. This is an absolute must if you are planning to use the MARPA functions and Chart Overlay on the radar/chartplotter. In the past it was necessary to buy a separate “fast heading sensor”. This is no longer required with modern pilots.
There are 2 downsides to the gyro. The first, predictably, is budget. The second is that it possible to drive a pilot much harder, and in much more extreme conditions, hence putting more stress on the pilot system. This is not a problem for a properly sized, installed and maintained system, but it will find the weak points if you have stinted on any of these.
Note the rate gyro should not be confused with the “gyro compass” used on commercial vessels.
Type of Steering
The issue here is simple. You have to find a drive type that is compatible with your steering type. All of the main manufacturers offer a broad range of drives for a range of steering types. The weight of the boat will define power of the drive, and hence the overall selection of the pilot – it’s back to that issue of weight again. Here are some generic notes on few of the more common types.
The use of hydraulics is widespread on both power and sail. Most autopilot manufacturers supply a range of hydraulic pumps to suit. These are split into broadly 2 types: Reversing Pumps (most common), and Constant Running Pumps.
Reversing Pumps only run when they are actually required to move the rudder, they run one way for starboard, and reverse direction for port. As well as the pump, they generally contain check and balance valves. Check valves ensure that when the pilot is off, the pump doesn’t affect the normal steering operation, balance valves allow the pump to be used with balanced and unbalanced steering rams.
Constant Running Pumps as the name suggests, run continuously when the pilots is on. The pilot switches electrical solenoid valve to control the flow of hydraulics to the steering ram. CR pumps as they are known, are used for larger pumps because it is very inefficient to start and stop larger electric motors.
Mechanical Steering – Power Boats
There are a range of drives and pilots for this type of installation. Some fit in front of the dash, between the helm unit and the steering wheel, and some fit behind the dash. Basically, the choice is down to looks versus space behind the console to fit more hardware, and it’s often a tight squeeze in a center console. There is one other consideration: manual override facility. This is most important for high speed sports and planning vessels. How easy is it to take control of the boat in the event of an emergency (floating debris, lobster pot etc in your path)? Some pilots offer immediate override without having to press any buttons—that is a definite advantage.
Mechanical Steering – Yachts
These drives fit into 2 main types: cockpit mounted drives, and below deck or inboard drives.
Cockpit drives tend to be fitted to lighter to mid end boats for occasional use. Inboard pilots are recommended for serious cruising and short-handed work.
Cockpit pilot drives split into 2 categories: tiller pilots and wheel pilots. Cockpit pilots can often be fitted by competent DIY captains and offer the perfect solution on a budget. Wheel pilots have a manual “clutch” that enable the drive to be engaged when it is in use. Tiller pilots are disconnected, simply by lifting them off the mounting pins.
Inboard drives are designed to be rugged and generally have longer lives. These drives often take single-handed sailors non- stop around the globe. There are 2 distinct types of drive. First there is the linear actuator. These drives are either fitted directly to the steering quadrant (or equivalent lay-quadrant) and work as a push/pull to operate the steering. The second type fits into the helm unit, either directly into the gearbox, or via a chain. All of these drives contain an electro mechanical clutch, controlled by the pilot to engage the drive when it is in use. When the pilot is disengaged, these drives offer very little residual drag, and hence to not detract from finely balanced steering systems with a high level of “feel”.
A word of warning: With the exception of tiller pilots (which are designed to be easily removed), these devices are all installed directly onto/into the ships steering. Pilot manufacturers go to great lengths to ensure that the installation procedure is as simple as possible, but it must be done correctly. For example, an inboard linear drive can create enough thrust to lift a small car, certainly enough thrust to punch a hole through a hull if it is incorrectly mounted, or comes loose. A hydraulic pump is mounted in the ships hydraulic circuit, if you lose the oil through a leak, or jam the helm through contamination, you will lose the ability to steer. It’s simple: if you’re not absolutely competent to install it, call in the professionals.
This is the point where you, as captain, get to make your mark on the selection of the autopilot. Up to now, the boat itself has guided the selection; now you get to be boss. This area is really up to personal choice, so here are a few tips on what to look for and consider.
Fixed control heads
Usually, there is one fixed head at each helm station, mounted within easy reach of the captain’s chair (or with a remote control – see later section). The single biggest factor here is ease of control of the pilot. That means large clear (and preferably separate) buttons for the main functions of engaging and disengaging the autopilot. Avoid systems that toggle between engaged and disengaged—this is one function where you cannot afford any ambiguity.
Control and adjustment of heading
There are two main schools of thought: rotary controls versus push button. Push buttons are very controllable and repeatable and you can dial in exact course changes by feel without looking at the display. Rotary controls offer a more fluid control, and is more naturally like steering the boat. There is a third option of offered as an accessory by some manufacturers—the joystick control. This will turn your autopilot into the ultimate computer game. Very cool, and great fun to use.
Switching between modes
There are as many options as there are manufacturers. The tip here is to really consider which modes you will really need and check how many button presses it takes to get into the mode you want. Does the display help guide you through?
The factors here are the same for any other piece of equipment: Size, clarity and brightness. Simple and uncluttered is usually the best. Up to date graphic displays show a range of information that helps with situational awareness (where is the track line, where is the waypoint, which way will I be turning, etc?) Older displays tend to be limited to heading (which in reality is not all that useful) and rudder angle (which is very useful, especially on a power boat). Another by-product is that some displays can be set up to be instrument repeaters. This can be especially useful for data that is related to pilot navigation such as cross track error, distance to waypoint, COG, SOG, etc.
Many manufacturers offer remote controls as an accessory. These may be simple left/right controls, up to multifunction controls and instrument repeaters. Fitting a wireless full function remote adds a new dimension of flexibility to boat operation, especially when short handed. It does not detract from the need for safe operation and watch keeping, but it does allow the pilot to be adjusted when away from the helm, especially useful when changing sails, adjusting fishing rigs, or picking up a mooring.
Final Selection of an Autopilot
Hopefully these notes have given you a good idea of what to look for and consider when selecting an autopilot; however this is no more than an overview. Correct selection, installation and set up are skilled tasks. Manufacturers have a wealth of knowledge and experience in selecting the correct size of pilot and drive. Use their experience at boat shows or dealerships.
As mentioned previously, installation is best left to the experts, fitting the components of a pilot is critical to the ships safety. Additionally, you may not get the full warranty and back up without the use of a certified installer. Check with your chosen manufacturer for details.