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Installing an Auto-pilot:

Look Ma! No Hands!

One of the gadgets we added to Toy Boat 2 was a Simrad AP12R autopilot. Luxury? Or irreplaceable tool?

Background   Installation   Commissioning   Performance   Safety, Reliability, Summary 

Fishing offshore often involves a lot of driving around. Here are some of the challenges that you face in a skiff:

  • A skiff might not track as well as larger boats, making it difficult for the captain to drive the boat while still helping to spot fish, watch the sonar, set up lines, etc.
  • Offshore fishing may require runs of 2 - 3 hours. It is difficult and fatiguing to steer a straight course over such a long distance, especially in a small boat which can easily be affected by chop and swell. You can also waste fuel by not steering a straight course.
  • If you fish alone, it can be almost impossible to aggressively fight a large fish without an autopilot, because you can not drive the boat while still applying maximum pressure on the fish.
  • Landing a fish might be difficult because if you only have one or two people aboard, it can be hard to maintain steerage if both people have to handle the fish.

These don't sound like very strong arguments for an autopilot, do they? Yet, after owning one for three years, we would have to say unequivocally that an autopilot is one of the best things we ever bought for the boat . We are less fatigued at the end of the day, use less fuel, and can spend much more time focused on fishing.

Underlying Concepts
An autopilot "just" steers the boat on a constant course. That course might be manually selected by the captain, or it might be supplied by a GPS or Loran device. But like most things in life, the actual mechanics of how this is done are a lot more complicated than you might think.

Because of wind, current and swell, at any given point in time the bow of your vessel could be pointed in a completely different direction from the course the boat is travelling, or needs to be travelling. If you simply lock the steering wheel in one position, the boat might track straight, but you will almost certainly be off-course in a matter of minutes. How well the autopilot recognizes that situation, and compensates for it, is the base criteria for evaluation how good the autopilot is.

For a more detailed look at autopilots and how they work, take a look at the West Marine Advisor on autopilots. Suffice to say, autopilots nowadays sport some pretty sophisticated electronics, and are "semi-intelligent" devices, meaning that they learn how to steer the boat based on prevailing sea conditions and boat position ("sea state").

Selecting the Unit
Autopilots have to be matched to:
  • The steering system - For small powerboats, the steering system is typically either a mechanical (cable) system with a rotary cable drum or a rack-and-pinion, or a hydraulic system. Toy Boat 2 uses a Teleflex NFB rotary cable steering system.

  • The type of steering wheel shaft being used - Most boats use a straight shaft, which holds the steering wheel at a fixed angle relative to the dashboard. However, the Edgewater 175CC came with a tilt steering wheel, similar to an automobile.

  • The size of your vessel - Clearly a bigger vessel required a more powerful drive unit. The capacity on most autopilots we looked at were well in excess of TB2's weight.

  • Whether or not you have multiple steering stations - Obviously, not an issue for us.

  • The capacity of the vessel's electrical system - Autopilots can consume a fair amount of power, so in a small boat you need to make sure your motor's alternator output and batteries can handle the extra load.

    Simrad AP12R
    Control Unit

For Toy Boat 2, we selected an arbitrary cutoff price of approximately $1,000. After all, this is only a 17.5 foot skiff, right? At the time, that left us with only two possible choices:

  • The Simrad / Robertson AP12R - Simrad also offers a sister unit called the AP14R, which differs only in the controller unit. The AP14R controller has an LCD display which shows heading information as sensed by the autopilot (useful in monitoring the system and debugging problems, as we'll see later).

    Raymarine Sport
    PilotPlus


  • The Raymarine SportPilot/SportPilot Plus - Based on a review of their installation manuals, the only difference between the two Sportpilot models is that the Plus model is designed for extended continuous use, such as cruising or trolling.



ComNav 1420

If we had hydraulic steering, our choices would have expanded to include:

  • ComNav 1420 - This unit sports an attractive price tag and most of the basic features, but at the time we were looking, was an unknown on the Internet bulletin boards we frequent.

Comparison

The AP12R is an under-dash unit, with the main electronics and drive unit replacing the stock rotary drum. Before purchasing this unit, you must make sure you have enough clearance behind the dash for the drive unit, which is fairly large (about the size of a loaf of bread). The AP12R has a controller which is designed to be permanently mounted on the dash, and is used to initiate navigation, make minor steering changes, and to calibrate the device. The AP14R controller has an LCD display which shows heading information and some status messages. It has a coiled cord with a mounting clip, and can be handheld.

The SportPilot Plus mounts on the end of the steering wheel shaft, and goes under the steering wheel. In order to counteract the torque of turning the wheel, the Sportpilot Plus also has a bracket which connects the bottom edge of the autopilot to the dashboard. This prevents the autopilot from spinning while turning the wheel. The bracket is articulated so that the autopilot can be used with a tilt steering wheel. It uses a lever on the unit (similar to a turn signal or cruise control lever on a car) and some exterior buttons on the face to provide control.

Base features on both units were very similar. Both units had their proponents and detractors on the Internet.

Decision

In the end, we decided to go with the Simrad, because it appeared that there were slightly fewer problems reported. But in reality, it could have gone either way.

We also initially thought the Simrad would work out better with our tilt wheel. But in fact, the SportPilot Plus would probably have worked with the tilt wheel using out-of-the-box parts, compared to the Simrad, which required a special shaft in order to connect to the tilt steering wheel mechanism.

Pricing worked out about the same for both units, right around our $1,000 target. We purchased the unit through Dave's Marine Electronics, based on price.

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