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Author Topic:   Autopilot: Compass and GPS or GPS-Only
David1877 posted 07-22-2008 12:43 AM ET (US)   Profile for David1877   Send Email to David1877  
I am contemplating the addition of the Raymarine S1000 or the Simrad AP24 to my Eastport (Conquest) 205. The Raymarine is less expensive. It navigates utilizing GPS receiver data. The Simrad utilizes feedback from a GPS receiver and data from a compass. The dealer asserts the Simrad is the better choice as it will be more responsive to wind and waves while trolling at slow speeds for salmon on Lake Michigan. I have read good reviews for both units.I can buy the Raymarine for about $1000. The Simrad sells for about $2500. Is the Simrad worth the money for my use?


jimh posted 07-22-2008 09:25 AM ET (US)     Profile for jimh  Send Email to jimh     
I can't offer any first-hand advice, nor can I judge the worth of the $1,500 difference in cost with regard to the performance that will be delivered, but I would like to note:

As you know, a Global Positioning System receiver (GPSr) deduces the vessel heading by comparing the present position with the previous position. When the vessel speed is low, the distance between positions used to deduce heading can become small. Any error in the position fix could introduce an error in the deduced heading.

A compass responds more directly to actual vessel heading, however, in waves the motion on a vessel can cause some error in the compass heading due to inertia in the compass card. My assumption is that the more expensive SIMRAD unit has its own electronic compass, and that compass probably has some sort of electronic dampening applied to reduce short term errors in heading.

The SIMRAD unit must have some algorithm for integrating the data from the two sources and deciding how to respond to them. It sounds like it is a more sophisticated device.

David1877 posted 07-22-2008 03:38 PM ET (US)     Profile for David1877  Send Email to David1877     

I agree. Apparently Raymarine has developed software to "learn" a boats handling characteristics.

Apparenlty technology is now good enough to control a boat electronially without a rudder sensor or compass. The hydraulic/electronic controls might be able to control the boat more quickly than a compass controlled unit with mechanical steering.

A friend has the old Raymarine Sport Pilot (similar boat) and it works ok for fishing Lake Michigan.

I have read reports of S1000 direction control problems below 3 knots, but apparently this problem has been corrected. The S1000 brochure states a minimum speed of 1.5 kts is required.

Users of the S1000 claim it performs flawlessly and most state no reservations about the unit.

Based on positive feedback, I will install the S1000 on my Eastport. I will post information on performace in about a week.


David1877 posted 07-22-2008 04:48 PM ET (US)     Profile for David1877  Send Email to David1877     
Key features of the S1000 Autopilot system include:

Wireless autopilot control from up to 32 feet from the base station.
Smooth course changes regardless of boat speed.
From Raymarine brochure. "Raymarine Smartsteer technology elimintes the need for remotely mounted rudder feedback and compass sensors assemblies. Thanks to Smartsteer technology the S1000 controls the proportional rate of turn relative to vessel speed, ensuring smooth and accurate helm control at both trolling and cruising speeds."

Automatic steering of fishing patterns
Intuitive, menu driven interface
Easy installation, designed for the do-it-yourselfer.
Designed for hydraulically steered vessels up to 25 feet in length, the S1000 autopilot system system consists of the following components:

S100 Wireless Controller
Two line display with a graphical autopilot status indicator
Crisp, high contrast 24 x 127 dot matrix display
Backlit display
Raised profile on Standby button for easy identification in the dark
Keylock security
Convenient replaceable AAA alkaline batteries

S1000 Autopilot Course Computer

Rugged, compact autopilot "brain" with SmartSteerâ„¢ technology
No compass or rudder reference unit required making for fast and easy installation
SeaTalk and NMEA 0183 Interfaces for connection to GPS** and instrumentation.
**A SeaTalk or NMEA 0183 compatible GPS receiver (sold separately)is required for autopilot operation.

glen e posted 07-22-2008 05:29 PM ET (US)     Profile for glen e  Send Email to glen e     
Believe me: the RAYMARINE unit is nowhere near "flawless," and, no, I have no axe to grind. But I owned three RAYMARINE units. The software was marginal, at best, with many upgrades. I was even a pilot test for the Verado RAYMARINE unit. [Archives of comments on the S1000 are on THT.]

I'd put a Simrad AP16 on the boat. The difference in a gyro-compass model versus a direct GPS model like the RAYMARINE is updating. It's far slower on the GPS-type and therefore does not hold a track as well, especially at below 5-MPH with a current or two to four-foot seas. Ask why RAYMARINE is the only one to use the GPS-type--it's not because it's a break-thru concept.

David1877 posted 07-23-2008 01:24 AM ET (US)     Profile for David1877  Send Email to David1877     

Thanks. I understand.

You get what you pay for.

Hopefully it will suit my needs ok.

I have emailed Raymarine about the possibility of adding a compass to this unit.

David1877 posted 07-23-2008 07:17 PM ET (US)     Profile for David1877  Send Email to David1877     
no compass available
David1877 posted 07-29-2008 06:39 PM ET (US)     Profile for David1877  Send Email to David1877     
I completed a sea trial today of my new autopilot on Lake Midhigan.

Waves were about 2 feet. Pretty good wind from the the SE.

I think the Raymarine S1000 performed well. I approached a sailing bouy and turned on the clover leaf fishing pattern. The unit steered the boat in large loops and brought the rig back around to the same spot near the buoy where I originated the patterns. This worked well at varying speeds including slow trolling speed.

The pump is a bit noisy but I have no other operational concerns with the unit.

David1877 posted 07-29-2008 10:32 PM ET (US)     Profile for David1877  Send Email to David1877     
My original post questioned the capabaility of the virtual autopilot control (GPS only) without the addition of a compass.

My concern was unfounded. I turned the unit on in the kenosha harbour at no wake speed and set it for a point at the end of the harbour. It performed flawlessly.

I think the unit gets COG data from the GPS at a rapid rate. It made very minor course changes witnessed by minor changes in motor position. It mantianed a nice true course towards the reference point. Once I was in open water, it maintined a straight heading in waves/wind and in varying directions. Heading verified on the compass.

It may not be as sensitive or as good/responsive as more expensive units with virtual and compass data, but I think it is sufficient to meet my needs. I am glad I saved the $1500.

pglein posted 08-04-2008 07:15 PM ET (US)     Profile for pglein  Send Email to pglein     
Are you sure that the Raymarine unit won't accept a compass bearing input? I had a Raymarine unit years ago (I want to say it was the S1000, but I'm not sure), that would do either. I don't think it would use both simultaneously or anything fancy like that, but I certainly had it set up to use the compass for the heading.
Plotman posted 08-05-2008 10:52 AM ET (US)     Profile for Plotman  Send Email to Plotman     
I believe I am on my third summer with the S1000.

There are several threads on here about my experience.

I "discovered" the 3 knot minimum after I installed it, and worked with my dealer and the Raymarine engineers in England as a guinea pig for their software updates that reduced the speed minimum to 1.2 kts. (My unit has been re-flashed several times as they have updated the program - the new minimum may be 1.5 now, mine is 1.2). They were great to deal with.

I have been very happy with how the S1000 works on my Outrage 22. I use it for fishing as well as cruising.

You are correct that you cannot add a compass other than a GPS, but you don't need one. GPS errors are repeatable over short periods of time, and they work fine for heading data if you get the settings for heading smoothing set right.

You do need to spend a few minutes reading the instructions, but I believe you will be quite pleased if you do.

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