CONTINUOUSWAVE

SIMRAD are offering an auto-pilot system that appears to use many of the same components as their sister-company Lowrance uses. Simrad calls their small boat auto-pilot device the DrivePilot. The Simrad DrivePilot auto-pilot consists of a bundle of components:

--the NAC-1 Auto Pilot Computer, containing the steering computer and electronics for the drive unit motor; this is the same device used in the Lowrance Outboard Pilot;

--the PUMP-1 Hydraulic Pump, a "super-quiet" 0.8-liter reversible hydraulic pump that is compatible with SeaStar steering systems, and can pump up to 14 cubic-inches.; this appear to be the same device as used in the Lowrance Outboard Pilot;

--the RC42 rate compass; this is a magnetic heading sensor and motion sensor but does not have a GNSS receiver; this substitutes for the POINT-1 used in the Lowrance Outboard Pilot;

--a hydraulic fitting kit for adapting the PUMP-1 pump to your hydraulic steering system;

--an AUTO/STAND BY button for changing mode

--a NMEA-2000 network kit consisting of a 4-way block, male and female terminators, a network power cable, a 2-feet-long network cable, and a 6-feet-long network cable; this package may be slightly different than the Lowrance bundled networking wiring appliances which seems to include a third cable;

The MSRP of the Simrad DrivePilot is $1,599. The system is capable of being used with the Simrad NSS evo2 or NSO evo2 multifunction display, but requires the evo2 software be the latest version. The Simrad webpage for this product in the USA is

http://www.simrad-yachting.com/en-US/Products/Autopilots/DrivePilot-Hydraulic-Steer-Pack-en-us.aspx

The RC42 rate compass is an enhanced magnetic compass and motion sensor. The normal MSRP of the RC42 is $679.

To compare the Simrad DrivePilot to the Lowrance Outboard Pilot, the most significant difference is the variation between the POINT-1 and RC42 sensors, and the MSRP of the bundles:

Lowrance Outboard Pilot MSRP = [can't find this listed on the Lowrance website, but it was $999]
Simrad DrivePilot MSRP = $1,599

Subtracting the $199 MSRP of the POINT-1 from the Outboard Pilot gives a base price of $800. Adding the RC-42 MSRP of $679 gives $1479 as a comparable value for the Simrad bundle. As the Simrad bundle price is $1,599, it appears to be priced about $120 above the Lowrance bundle, based on the MSRP of comparable components. Lowrance also throws in one extra network cable in their bundle.

Buried in the product description on the Simrad website is this: "steering systems on inboard and single or double outboard vessels under 10 m (35 ft).". The Lowrance version can only handle single outboards.

http://www.simrad-yachting.com/en-US/Products/Autopilots/DrivePilot-Hydraulic-Steer-Pack-en-us.aspx

For the Lowrance Outboard Pilot unit: "Recommended for single-outboard setups, on boats that are 30 feet and less, in length."

http://www.lowrance.com/en-US/Products/Auto-Steering/Outboard-Pilot-Hydraulic-Pack-en-us.aspx

It looks like both units use the same pump. Unless the more expensive RC42 heading sensor would make the difference [i.e., the difference in being rated for use with twin engines], I wonder why the Lowrance is rated less than the Simrad.

In certain conditions, my Lowrance unit seems to under-steer or over-steer quite a bit. I wonder if this is attributable to the lesser heading sensor?

The RC42 rate compass does provide motion data to the auto-pilot computer at a rate of 20-Hz. And it does have motion sensors. Perhaps the RC42 rate compass is preferable to the POINT-1 GNSS receiver and magnetic heading sensor as a part of the steering automation system.

An outboard boat with twin engine may be generally considered as having a faster boat speed than one with single engines, so perhaps the endorsement of the Simrad DrivePilot auto-pilot for twin engine boats is related to the boat speed and the faster update rate of the RC42 rate compass.

I don't know if the POINT-1 has motion sensors. Its heading sensor output may be limited to 10-Hz.

Re boats with twins are generally considered faster than boats with single engines- what's the difference if a boat has a single 300 or twin 150 hp motors?

And I wouldn't think there'd be much of a difference between a refresh rate of 10 and 20 times a second unless you were literally flying.

The RC42 probably is better because it probably has better damping and perhaps better accuracy in rough seas. Other larger boats with autopilots that I've operated had problems holding a course in a following sea, sometimes actually disengaging the autopilot because of excessive error.

The RC42 lacks a GNSS receiver and still sells at more than three time the price of a POINT-1. It must be a better rate compass.

The distinction between the Lowrance and Simrad small-boat auto-pilots could also just be reflective of the general division of markets intended for those product lines. Lowrance products are aimed at inland, freshwater fishing boats. There are not too many twin engine bass boats. Simrad products are aimed at offshore saltwater boats. Those boats are much more likely to have twin engines.

As evidence, I report this anecdote: many years ago we trailered our then twin-engine Boston Whaler boat to Lake of the Ozarks. We were cruising along one day, enjoying fine October weather and a completely deserted lake, devoid of almost all boating activity. We passed by a very interesting boat on a hoist along the shore. We came closer to look at it. I think it was a Stamas express cruiser. The owner was on his dock, and we stopped to chat. I remarked on his boat, and he remarked on mine. He said to me, "I knew you weren't from around here, because we never see any Boston Whalers with twin engines." There you have it, QED.