Autopilot Selection and Installation
This Mariner 36 once had an electric belt driven wheel pilot. It failed and was not replace by a prior owner. The pulley on the ships wheel was easily removed, plus the bracket where the wheel pilot had been mounted. This will later be replaced with a linear electric quadrant mounted autopilot. An emergency tiller should also be purchased if possible or built.
Autopilots come in four basic types:
- tiller pilots for tiller steering,
- wheel pilots,
- linear electric motor driven, and
- linear hydraulic driven.
Tiller pilots are not an option with wheel steering. I would like to avoid oils, diesel, or gas and also hydraulic fluid on the boat. This leaves wheel pilots and linear electric motor driven autopilots. The belt driven wheel pilots are notorious for slipping under load. Direct drive wheel pilots are a bulky addition to the steering pedestal and are underpowered for a 16,000-17,000 lb boat.
The autopilots considered are all Raymarine Evolution Series Autopilots.
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The T70152 EV-100 is a wheel driven system available in clutch driven pedestal mount for wheel steering. It is rated for a vessel up to 16,500 lbs. Price (as of Oct 2019) at Defender is $1,229.99.
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The T70158 EV-200 Linear Drive is a 12V mechanical linear electric motor driven system. It is rated for vessels up to 24,000 lbs. Price (as of Oct 2019) at Defender is $3,299.99.
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The EV-400 series offers linear electric motor drives for larger boats at a substantially greater cost than the EV-200 series. Price (as of Oct 2019) are $2,999.99 for the control system, $1,890.99 for the drive, for $4,890.98 total. This unit is costly and oversized for this boat.
Raymarine provides a summary of linear drives rates to vessel sizes of 24,000 lb, 33,000 lb, or 44,000 lb. Since the Mariner 36 ketch is a 17,000 lb vessel, the wheel drive is undersized and the EV-200 Linear has capacity to spare though at a higher cost that the wheel driven autopilot.